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| * | nohz: New tick dependency maskFrederic Weisbecker2016-03-02
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The tick dependency is evaluated on every IRQ and context switch. This consists is a batch of checks which determine whether it is safe to stop the tick or not. These checks are often split in many details: posix cpu timers, scheduler, sched clock, perf events.... each of which are made of smaller details: posix cpu timer involves checking process wide timers then thread wide timers. Perf involves checking freq events then more per cpu details. Checking these informations asynchronously every time we update the full dynticks state bring avoidable overhead and a messy layout. Let's introduce instead tick dependency masks: one for system wide dependency (unstable sched clock, freq based perf events), one for CPU wide dependency (sched, throttling perf events), and task/signal level dependencies (posix cpu timers). The subsystems are responsible for setting and clearing their dependency through a set of APIs that will take care of concurrent dependency mask modifications and kick targets to restart the relevant CPU tick whenever needed. This new dependency engine stays beside the old one until all subsystems having a tick dependency are converted to it. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Suggested-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* | sched/deadline: Remove dl_new from struct sched_dl_entityLuca Abeni2016-03-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The dl_new field of struct sched_dl_entity is currently used to identify new deadline tasks, so that their deadline and runtime can be properly initialised. However, these tasks can be easily identified by checking if their deadline is smaller than the current time when they switch to SCHED_DEADLINE. So, dl_new can be removed by introducing this check in switched_to_dl(); this allows to simplify the SCHED_DEADLINE code. Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1457350024-7825-2-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched/debug: Fix preempt_disable_ip recording for preempt_disable()Sebastian Andrzej Siewior2016-02-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The preempt_disable() invokes preempt_count_add() which saves the caller in ->preempt_disable_ip. It uses CALLER_ADDR1 which does not look for its caller but for the parent of the caller. Which means we get the correct caller for something like spin_lock() unless the architectures inlines those invocations. It is always wrong for preempt_disable() or local_bh_disable(). This patch makes the function get_lock_parent_ip() which tries CALLER_ADDR0,1,2 if the former is a locking function. This seems to record the preempt_disable() caller properly for preempt_disable() itself as well as for get_cpu_var() or local_bh_disable(). Steven asked for the get_parent_ip() -> get_lock_parent_ip() rename. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160226135456.GB18244@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched/rt: Fix PI handling vs. sched_setscheduler()Peter Zijlstra2016-02-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andrea Parri reported: > I found that the following scenario (with CONFIG_RT_GROUP_SCHED=y) is not > handled correctly: > > T1 (prio = 20) > lock(rtmutex); > > T2 (prio = 20) > blocks on rtmutex (rt_nr_boosted = 0 on T1's rq) > > T1 (prio = 20) > sys_set_scheduler(prio = 0) > [new_effective_prio == oldprio] > T1 prio = 20 (rt_nr_boosted = 0 on T1's rq) > > The last step is incorrect as T1 is now boosted (c.f., rt_se_boosted()); > in particular, if we continue with > > T1 (prio = 20) > unlock(rtmutex) > wakeup(T2) > adjust_prio(T1) > [prio != rt_mutex_getprio(T1)] > dequeue(T1) > rt_nr_boosted = (unsigned long)(-1) > ... > T1 prio = 0 > > then we end up leaving rt_nr_boosted in an "inconsistent" state. > > The simple program attached could reproduce the previous scenario; note > that, as a consequence of the presence of this state, the "assertion" > > WARN_ON(!rt_nr_running && rt_nr_boosted) > > from dec_rt_group() may trigger. So normally we dequeue/enqueue tasks in sched_setscheduler(), which would ensure the accounting stays correct. However in the early PI path we fail to do so. So this was introduced at around v3.14, by: c365c292d059 ("sched: Consider pi boosting in setscheduler()") which fixed another problem exactly because that dequeue/enqueue, joy. Fix this by teaching rt about DEQUEUE_SAVE/ENQUEUE_RESTORE and have it preserve runqueue location with that option. This requires decoupling the on_rt_rq() state from being on the list. In order to allow for explicit movement during the SAVE/RESTORE, introduce {DE,EN}QUEUE_MOVE. We still must use SAVE/RESTORE in these cases to preserve other invariants. Respecting the SAVE/RESTORE flags also has the (nice) side-effect that things like sys_nice()/sys_sched_setaffinity() also do not reorder FIFO tasks (whereas they used to before this patch). Reported-by: Andrea Parri <parri.andrea@gmail.com> Tested-by: Andrea Parri <parri.andrea@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched/debug: Make schedstats a runtime tunable that is disabled by defaultMel Gorman2016-02-09
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | schedstats is very useful during debugging and performance tuning but it incurs overhead to calculate the stats. As such, even though it can be disabled at build time, it is often enabled as the information is useful. This patch adds a kernel command-line and sysctl tunable to enable or disable schedstats on demand (when it's built in). It is disabled by default as someone who knows they need it can also learn to enable it when necessary. The benefits are dependent on how scheduler-intensive the workload is. If it is then the patch reduces the number of cycles spent calculating the stats with a small benefit from reducing the cache footprint of the scheduler. These measurements were taken from a 48-core 2-socket machine with Xeon(R) E5-2670 v3 cpus although they were also tested on a single socket machine 8-core machine with Intel i7-3770 processors. netperf-tcp 4.5.0-rc1 4.5.0-rc1 vanilla nostats-v3r1 Hmean 64 560.45 ( 0.00%) 575.98 ( 2.77%) Hmean 128 766.66 ( 0.00%) 795.79 ( 3.80%) Hmean 256 950.51 ( 0.00%) 981.50 ( 3.26%) Hmean 1024 1433.25 ( 0.00%) 1466.51 ( 2.32%) Hmean 2048 2810.54 ( 0.00%) 2879.75 ( 2.46%) Hmean 3312 4618.18 ( 0.00%) 4682.09 ( 1.38%) Hmean 4096 5306.42 ( 0.00%) 5346.39 ( 0.75%) Hmean 8192 10581.44 ( 0.00%) 10698.15 ( 1.10%) Hmean 16384 18857.70 ( 0.00%) 18937.61 ( 0.42%) Small gains here, UDP_STREAM showed nothing intresting and neither did the TCP_RR tests. The gains on the 8-core machine were very similar. tbench4 4.5.0-rc1 4.5.0-rc1 vanilla nostats-v3r1 Hmean mb/sec-1 500.85 ( 0.00%) 522.43 ( 4.31%) Hmean mb/sec-2 984.66 ( 0.00%) 1018.19 ( 3.41%) Hmean mb/sec-4 1827.91 ( 0.00%) 1847.78 ( 1.09%) Hmean mb/sec-8 3561.36 ( 0.00%) 3611.28 ( 1.40%) Hmean mb/sec-16 5824.52 ( 0.00%) 5929.03 ( 1.79%) Hmean mb/sec-32 10943.10 ( 0.00%) 10802.83 ( -1.28%) Hmean mb/sec-64 15950.81 ( 0.00%) 16211.31 ( 1.63%) Hmean mb/sec-128 15302.17 ( 0.00%) 15445.11 ( 0.93%) Hmean mb/sec-256 14866.18 ( 0.00%) 15088.73 ( 1.50%) Hmean mb/sec-512 15223.31 ( 0.00%) 15373.69 ( 0.99%) Hmean mb/sec-1024 14574.25 ( 0.00%) 14598.02 ( 0.16%) Hmean mb/sec-2048 13569.02 ( 0.00%) 13733.86 ( 1.21%) Hmean mb/sec-3072 12865.98 ( 0.00%) 13209.23 ( 2.67%) Small gains of 2-4% at low thread counts and otherwise flat. The gains on the 8-core machine were slightly different tbench4 on 8-core i7-3770 single socket machine Hmean mb/sec-1 442.59 ( 0.00%) 448.73 ( 1.39%) Hmean mb/sec-2 796.68 ( 0.00%) 794.39 ( -0.29%) Hmean mb/sec-4 1322.52 ( 0.00%) 1343.66 ( 1.60%) Hmean mb/sec-8 2611.65 ( 0.00%) 2694.86 ( 3.19%) Hmean mb/sec-16 2537.07 ( 0.00%) 2609.34 ( 2.85%) Hmean mb/sec-32 2506.02 ( 0.00%) 2578.18 ( 2.88%) Hmean mb/sec-64 2511.06 ( 0.00%) 2569.16 ( 2.31%) Hmean mb/sec-128 2313.38 ( 0.00%) 2395.50 ( 3.55%) Hmean mb/sec-256 2110.04 ( 0.00%) 2177.45 ( 3.19%) Hmean mb/sec-512 2072.51 ( 0.00%) 2053.97 ( -0.89%) In constract, this shows a relatively steady 2-3% gain at higher thread counts. Due to the nature of the patch and the type of workload, it's not a surprise that the result will depend on the CPU used. hackbench-pipes 4.5.0-rc1 4.5.0-rc1 vanilla nostats-v3r1 Amean 1 0.0637 ( 0.00%) 0.0660 ( -3.59%) Amean 4 0.1229 ( 0.00%) 0.1181 ( 3.84%) Amean 7 0.1921 ( 0.00%) 0.1911 ( 0.52%) Amean 12 0.3117 ( 0.00%) 0.2923 ( 6.23%) Amean 21 0.4050 ( 0.00%) 0.3899 ( 3.74%) Amean 30 0.4586 ( 0.00%) 0.4433 ( 3.33%) Amean 48 0.5910 ( 0.00%) 0.5694 ( 3.65%) Amean 79 0.8663 ( 0.00%) 0.8626 ( 0.43%) Amean 110 1.1543 ( 0.00%) 1.1517 ( 0.22%) Amean 141 1.4457 ( 0.00%) 1.4290 ( 1.16%) Amean 172 1.7090 ( 0.00%) 1.6924 ( 0.97%) Amean 192 1.9126 ( 0.00%) 1.9089 ( 0.19%) Some small gains and losses and while the variance data is not included, it's close to the noise. The UMA machine did not show anything particularly different pipetest 4.5.0-rc1 4.5.0-rc1 vanilla nostats-v2r2 Min Time 4.13 ( 0.00%) 3.99 ( 3.39%) 1st-qrtle Time 4.38 ( 0.00%) 4.27 ( 2.51%) 2nd-qrtle Time 4.46 ( 0.00%) 4.39 ( 1.57%) 3rd-qrtle Time 4.56 ( 0.00%) 4.51 ( 1.10%) Max-90% Time 4.67 ( 0.00%) 4.60 ( 1.50%) Max-93% Time 4.71 ( 0.00%) 4.65 ( 1.27%) Max-95% Time 4.74 ( 0.00%) 4.71 ( 0.63%) Max-99% Time 4.88 ( 0.00%) 4.79 ( 1.84%) Max Time 4.93 ( 0.00%) 4.83 ( 2.03%) Mean Time 4.48 ( 0.00%) 4.39 ( 1.91%) Best99%Mean Time 4.47 ( 0.00%) 4.39 ( 1.91%) Best95%Mean Time 4.46 ( 0.00%) 4.38 ( 1.93%) Best90%Mean Time 4.45 ( 0.00%) 4.36 ( 1.98%) Best50%Mean Time 4.36 ( 0.00%) 4.25 ( 2.49%) Best10%Mean Time 4.23 ( 0.00%) 4.10 ( 3.13%) Best5%Mean Time 4.19 ( 0.00%) 4.06 ( 3.20%) Best1%Mean Time 4.13 ( 0.00%) 4.00 ( 3.39%) Small improvement and similar gains were seen on the UMA machine. The gain is small but it stands to reason that doing less work in the scheduler is a good thing. The downside is that the lack of schedstats and tracepoints may be surprising to experts doing performance analysis until they find the existence of the schedstats= parameter or schedstats sysctl. It will be automatically activated for latencytop and sleep profiling to alleviate the problem. For tracepoints, there is a simple warning as it's not safe to activate schedstats in the context when it's known the tracepoint may be wanted but is unavailable. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk> Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <mgalbraith@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1454663316-22048-1-git-send-email-mgorman@techsingularity.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2016-01-22
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: "Embarrassing braino fix + pipe page accounting + fixing an eyesore in find_filesystem() (checking that s1 is equal to prefix of s2 of given length can be done in many ways, but "compare strlen(s1) with length and then do strncmp()" is not a good one...)" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: [regression] fix braino in fs/dlm/user.c pipe: limit the per-user amount of pages allocated in pipes find_filesystem(): simplify comparison
| * pipe: limit the per-user amount of pages allocated in pipesWilly Tarreau2016-01-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On no-so-small systems, it is possible for a single process to cause an OOM condition by filling large pipes with data that are never read. A typical process filling 4000 pipes with 1 MB of data will use 4 GB of memory. On small systems it may be tricky to set the pipe max size to prevent this from happening. This patch makes it possible to enforce a per-user soft limit above which new pipes will be limited to a single page, effectively limiting them to 4 kB each, as well as a hard limit above which no new pipes may be created for this user. This has the effect of protecting the system against memory abuse without hurting other users, and still allowing pipes to work correctly though with less data at once. The limit are controlled by two new sysctls : pipe-user-pages-soft, and pipe-user-pages-hard. Both may be disabled by setting them to zero. The default soft limit allows the default number of FDs per process (1024) to create pipes of the default size (64kB), thus reaching a limit of 64MB before starting to create only smaller pipes. With 256 processes limited to 1024 FDs each, this results in 1024*64kB + (256*1024 - 1024) * 4kB = 1084 MB of memory allocated for a user. The hard limit is disabled by default to avoid breaking existing applications that make intensive use of pipes (eg: for splicing). Reported-by: socketpair@gmail.com Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Mitigates: CVE-2013-4312 (Linux 2.0+) Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | mm: memcontrol: move kmem accounting code to CONFIG_MEMCGJohannes Weiner2016-01-20
| | | | | | | | | | | | | | | | | | | | | | | | The cgroup2 memory controller will account important in-kernel memory consumers per default. Move all necessary components to CONFIG_MEMCG. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | UBSAN: run-time undefined behavior sanity checkerAndrey Ryabinin2016-01-20
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | UBSAN uses compile-time instrumentation to catch undefined behavior (UB). Compiler inserts code that perform certain kinds of checks before operations that could cause UB. If check fails (i.e. UB detected) __ubsan_handle_* function called to print error message. So the most of the work is done by compiler. This patch just implements ubsan handlers printing errors. GCC has this capability since 4.9.x [1] (see -fsanitize=undefined option and its suboptions). However GCC 5.x has more checkers implemented [2]. Article [3] has a bit more details about UBSAN in the GCC. [1] - https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html [2] - https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html [3] - http://developerblog.redhat.com/2014/10/16/gcc-undefined-behavior-sanitizer-ubsan/ Issues which UBSAN has found thus far are: Found bugs: * out-of-bounds access - 97840cb67ff5 ("netfilter: nfnetlink: fix insufficient validation in nfnetlink_bind") undefined shifts: * d48458d4a768 ("jbd2: use a better hash function for the revoke table") * 10632008b9e1 ("clockevents: Prevent shift out of bounds") * 'x << -1' shift in ext4 - http://lkml.kernel.org/r/<5444EF21.8020501@samsung.com> * undefined rol32(0) - http://lkml.kernel.org/r/<1449198241-20654-1-git-send-email-sasha.levin@oracle.com> * undefined dirty_ratelimit calculation - http://lkml.kernel.org/r/<566594E2.3050306@odin.com> * undefined roundown_pow_of_two(0) - http://lkml.kernel.org/r/<1449156616-11474-1-git-send-email-sasha.levin@oracle.com> * [WONTFIX] undefined shift in __bpf_prog_run - http://lkml.kernel.org/r/<CACT4Y+ZxoR3UjLgcNdUm4fECLMx2VdtfrENMtRRCdgHB2n0bJA@mail.gmail.com> WONTFIX here because it should be fixed in bpf program, not in kernel. signed overflows: * 32a8df4e0b33f ("sched: Fix odd values in effective_load() calculations") * mul overflow in ntp - http://lkml.kernel.org/r/<1449175608-1146-1-git-send-email-sasha.levin@oracle.com> * incorrect conversion into rtc_time in rtc_time64_to_tm() - http://lkml.kernel.org/r/<1449187944-11730-1-git-send-email-sasha.levin@oracle.com> * unvalidated timespec in io_getevents() - http://lkml.kernel.org/r/<CACT4Y+bBxVYLQ6LtOKrKtnLthqLHcw-BMp3aqP3mjdAvr9FULQ@mail.gmail.com> * [NOTABUG] signed overflow in ktime_add_safe() - http://lkml.kernel.org/r/<CACT4Y+aJ4muRnWxsUe1CMnA6P8nooO33kwG-c8YZg=0Xc8rJqw@mail.gmail.com> [akpm@linux-foundation.org: fix unused local warning] [akpm@linux-foundation.org: fix __int128 build woes] Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Marek <mmarek@suse.cz> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Yury Gribov <y.gribov@samsung.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds2016-01-12
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull networking updates from Davic Miller: 1) Support busy polling generically, for all NAPI drivers. From Eric Dumazet. 2) Add byte/packet counter support to nft_ct, from Floriani Westphal. 3) Add RSS/XPS support to mvneta driver, from Gregory Clement. 4) Implement IPV6_HDRINCL socket option for raw sockets, from Hannes Frederic Sowa. 5) Add support for T6 adapter to cxgb4 driver, from Hariprasad Shenai. 6) Add support for VLAN device bridging to mlxsw switch driver, from Ido Schimmel. 7) Add driver for Netronome NFP4000/NFP6000, from Jakub Kicinski. 8) Provide hwmon interface to mlxsw switch driver, from Jiri Pirko. 9) Reorganize wireless drivers into per-vendor directories just like we do for ethernet drivers. From Kalle Valo. 10) Provide a way for administrators "destroy" connected sockets via the SOCK_DESTROY socket netlink diag operation. From Lorenzo Colitti. 11) Add support to add/remove multicast routes via netlink, from Nikolay Aleksandrov. 12) Make TCP keepalive settings per-namespace, from Nikolay Borisov. 13) Add forwarding and packet duplication facilities to nf_tables, from Pablo Neira Ayuso. 14) Dead route support in MPLS, from Roopa Prabhu. 15) TSO support for thunderx chips, from Sunil Goutham. 16) Add driver for IBM's System i/p VNIC protocol, from Thomas Falcon. 17) Rationalize, consolidate, and more completely document the checksum offloading facilities in the networking stack. From Tom Herbert. 18) Support aborting an ongoing scan in mac80211/cfg80211, from Vidyullatha Kanchanapally. 19) Use per-bucket spinlock for bpf hash facility, from Tom Leiming. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1375 commits) net: bnxt: always return values from _bnxt_get_max_rings net: bpf: reject invalid shifts phonet: properly unshare skbs in phonet_rcv() dwc_eth_qos: Fix dma address for multi-fragment skbs phy: remove an unneeded condition mdio: remove an unneed condition mdio_bus: NULL dereference on allocation error net: Fix typo in netdev_intersect_features net: freescale: mac-fec: Fix build error from phy_device API change net: freescale: ucc_geth: Fix build error from phy_device API change bonding: Prevent IPv6 link local address on enslaved devices IB/mlx5: Add flow steering support net/mlx5_core: Export flow steering API net/mlx5_core: Make ipv4/ipv6 location more clear net/mlx5_core: Enable flow steering support for the IB driver net/mlx5_core: Initialize namespaces only when supported by device net/mlx5_core: Set priority attributes net/mlx5_core: Connect flow tables net/mlx5_core: Introduce modify flow table command net/mlx5_core: Managing root flow table ...
| * unix: properly account for FDs passed over unix socketswilly tarreau2016-01-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is possible for a process to allocate and accumulate far more FDs than the process' limit by sending them over a unix socket then closing them to keep the process' fd count low. This change addresses this problem by keeping track of the number of FDs in flight per user and preventing non-privileged processes from having more FDs in flight than their configured FD limit. Reported-by: socketpair@gmail.com Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Mitigates: CVE-2013-4312 (Linux 2.0+) Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: David S. Miller <davem@davemloft.net>
* | Merge branch 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wqLinus Torvalds2016-01-11
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull workqueue update from Tejun Heo: "Workqueue changes for v4.5. One cleanup patch and three to improve the debuggability. Workqueue now has a stall detector which dumps workqueue state if any worker pool hasn't made forward progress over a certain amount of time (30s by default) and also triggers a warning if a workqueue which can be used in memory reclaim path tries to wait on something which can't be. These should make workqueue hangs a lot easier to debug." * 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: simplify the apply_workqueue_attrs_locked() workqueue: implement lockup detector watchdog: introduce touch_softlockup_watchdog_sched() workqueue: warn if memory reclaim tries to flush !WQ_MEM_RECLAIM workqueue
| * | watchdog: introduce touch_softlockup_watchdog_sched()Tejun Heo2015-12-08
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | touch_softlockup_watchdog() is used to tell watchdog that scheduler stall is expected. One group of usage is from paths where the task may not be able to yield for a long time such as performing slow PIO to finicky device and coming out of suspend. The other is to account for scheduler and timer going idle. For scheduler softlockup detection, there's no reason to distinguish the two cases; however, workqueue lockup detector is planned and it can use the same signals from the former group while the latter would spuriously prevent detection. This patch introduces a new function touch_softlockup_watchdog_sched() and convert the latter group to call it instead. For now, it just calls touch_softlockup_watchdog() and there's no functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ulrich Obergfell <uobergfe@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org>
* | sched/core: Move sched_entity::avg into separate cache lineJiri Olsa2016-01-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sched_entity::avg collides with read-mostly sched_entity data. The perf c2c tool showed many read HITM accesses across many CPUs for sched_entity's cfs_rq and my_q, while having at the same time tons of stores for avg. After placing sched_entity::avg into separate cache line, the perf bench sched pipe showed around 20 seconds speedup. NOTE I cut out all perf events except for cycles and instructions from following output. Before: $ perf stat -r 5 perf bench sched pipe -l 10000000 # Running 'sched/pipe' benchmark: # Executed 10000000 pipe operations between two processes Total time: 270.348 [sec] 27.034805 usecs/op 36989 ops/sec ... 245,537,074,035 cycles # 1.433 GHz 187,264,548,519 instructions # 0.77 insns per cycle 272.653840535 seconds time elapsed ( +- 1.31% ) After: $ perf stat -r 5 perf bench sched pipe -l 10000000 # Running 'sched/pipe' benchmark: # Executed 10000000 pipe operations between two processes Total time: 251.076 [sec] 25.107678 usecs/op 39828 ops/sec ... 244,573,513,928 cycles # 1.572 GHz 187,409,641,157 instructions # 0.76 insns per cycle 251.679315188 seconds time elapsed ( +- 0.31% ) Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Don Zickus <dzickus@redhat.com> Cc: Joe Mario <jmario@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1449606239-28602-1-git-send-email-jolsa@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | Merge branch 'sched/urgent' into sched/core, to pick up fixes before merging ↵Ingo Molnar2016-01-06
|\ \ | | | | | | | | | | | | | | | new patches Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | sched/core: Fix unserialized r-m-w scribbling stuffPeter Zijlstra2016-01-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some of the sched bitfieds (notably sched_reset_on_fork) can be set on other than current, this can cause the r-m-w to race with other updates. Since all the sched bits are serialized by scheduler locks, pull them in a separate word. Reported-by: Tejun Heo <tj@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: hannes@cmpxchg.org Cc: mhocko@kernel.org Cc: vdavydov@parallels.com Link: http://lkml.kernel.org/r/20151125150207.GM11639@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | sched/core: Check tgid in is_global_init()Sergey Senozhatsky2016-01-06
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Our global init task can have sub-threads, so ->pid check is not reliable enough for is_global_init(), we need to check tgid instead. This has been spotted by Oleg and a fix was proposed by Richard a long time ago (see the link below). Oleg wrote: : Because is_global_init() is only true for the main thread of /sbin/init. : : Just look at oom_unkillable_task(). It tries to not kill init. But, say, : select_bad_process() can happily find a sub-thread of is_global_init() : and still kill it. I recently hit the problem in question; re-sending the patch (to the best of my knowledge it has never been submitted) with updated function comment. Credit goes to Oleg and Richard. Suggested-by: Richard Guy Briggs <rgb@redhat.com> Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Eric W . Biederman <ebiederm@xmission.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Serge E . Hallyn <serge.hallyn@ubuntu.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://www.redhat.com/archives/linux-audit/2013-December/msg00086.html Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched/cputime: Convert vtime_seqlock to seqcountFrederic Weisbecker2015-12-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The cputime can only be updated by the current task itself, even in vtime case. So we can safely use seqcount instead of seqlock as there is no writer concurrency involved. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1447948054-28668-8-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched/cputime: Clarify vtime symbols and document themFrederic Weisbecker2015-12-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | VTIME_SLEEPING state happens either when: 1) The task is sleeping and no tickless delta is to be added on the task cputime stats. 2) The CPU isn't running vtime at all, so the same properties of 1) applies. Lets rename the vtime symbol to reflect both states. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1447948054-28668-4-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched/fair: Consider missed ticks in NOHZ_FULL in update_cpu_load_nohz()Byungchul Park2015-11-23
|/ | | | | | | | | | | | | | | | | | | Usually the tick can be stopped for an idle CPU in NOHZ. However in NOHZ_FULL mode, a non-idle CPU's tick can also be stopped. However, update_cpu_load_nohz() does not consider the case a non-idle CPU's tick has been stopped at all. This patch makes the update_cpu_load_nohz() know if the calling path comes from NOHZ_FULL or idle NOHZ. Signed-off-by: Byungchul Park <byungchul.park@lge.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1447115762-19734-3-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge tag 'libnvdimm-for-4.4' of ↵Linus Torvalds2015-11-10
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull libnvdimm updates from Dan Williams: "Outside of the new ACPI-NFIT hot-add support this pull request is more notable for what it does not contain, than what it does. There were a handful of development topics this cycle, dax get_user_pages, dax fsync, and raw block dax, that need more more iteration and will wait for 4.5. The patches to make devm and the pmem driver NUMA aware have been in -next for several weeks. The hot-add support has not, but is contained to the NFIT driver and is passing unit tests. The coredump support is straightforward and was looked over by Jeff. All of it has received a 0day build success notification across 107 configs. Summary: - Add support for the ACPI 6.0 NFIT hot add mechanism to process updates of the NFIT at runtime. - Teach the coredump implementation how to filter out DAX mappings. - Introduce NUMA hints for allocations made by the pmem driver, and as a side effect all devm allocations now hint their NUMA node by default" * tag 'libnvdimm-for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: coredump: add DAX filtering for FDPIC ELF coredumps coredump: add DAX filtering for ELF coredumps acpi: nfit: Add support for hot-add nfit: in acpi_nfit_init, break on a 0-length table pmem, memremap: convert to numa aware allocations devm_memremap_pages: use numa_mem_id devm: make allocations numa aware by default devm_memremap: convert to return ERR_PTR devm_memunmap: use devres_release() pmem: kill memremap_pmem() x86, mm: quiet arch_add_memory()
| * coredump: add DAX filtering for ELF coredumpsRoss Zwisler2015-11-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add two new flags to the existing coredump mechanism for ELF files to allow us to explicitly filter DAX mappings. This is desirable because DAX mappings, like hugetlb mappings, have the potential to be very large. Update the coredump_filter documentation in Documentation/filesystems/proc.txt so that it addresses the new DAX coredump flags. Also update the documented default value of coredump_filter to be consistent with the core(5) man page. The documentation being updated talks about bit 4, Dump ELF headers, which is enabled if CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is turned on in the kernel config. This kernel config option defaults to "y" if both ELF binaries and coredump are enabled. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Acked-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* | signal: introduce kernel_signal_stop() to fix jffs2_garbage_collect_thread()Oleg Nesterov2015-11-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | jffs2_garbage_collect_thread() can race with SIGCONT and sleep in TASK_STOPPED state after it was already sent. Add the new helper, kernel_signal_stop(), which does this correctly. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Tejun Heo <tj@kernel.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Felipe Balbi <balbi@ti.com> Cc: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | signal: turn dequeue_signal_lock() into kernel_dequeue_signal()Oleg Nesterov2015-11-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1. Rename dequeue_signal_lock() to kernel_dequeue_signal(). This matches another "for kthreads only" kernel_sigaction() helper. 2. Remove the "tsk" and "mask" arguments, they are always current and current->blocked. And it is simply wrong if tsk != current. 3. We could also remove the 3rd "siginfo_t *info" arg but it looks potentially useful. However we can simplify the callers if we change kernel_dequeue_signal() to accept info => NULL. 4. Remove _irqsave, it is never called from atomic context. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Tejun Heo <tj@kernel.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Felipe Balbi <balbi@ti.com> Cc: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | signals: kill block_all_signals() and unblock_all_signals()Oleg Nesterov2015-11-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is hardly possible to enumerate all problems with block_all_signals() and unblock_all_signals(). Just for example, 1. block_all_signals(SIGSTOP/etc) simply can't help if the caller is multithreaded. Another thread can dequeue the signal and force the group stop. 2. Even is the caller is single-threaded, it will "stop" anyway. It will not sleep, but it will spin in kernel space until SIGCONT or SIGKILL. And a lot more. In short, this interface doesn't work at all, at least the last 10+ years. Daniel said: Yeah the only times I played around with the DRM_LOCK stuff was when old drivers accidentally deadlocked - my impression is that the entire DRM_LOCK thing was never really tested properly ;-) Hence I'm all for purging where this leaks out of the drm subsystem. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Dave Airlie <airlied@redhat.com> Cc: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'akpm' (patches from Andrew)Linus Torvalds2015-11-06
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge patch-bomb from Andrew Morton: - inotify tweaks - some ocfs2 updates (many more are awaiting review) - various misc bits - kernel/watchdog.c updates - Some of mm. I have a huge number of MM patches this time and quite a lot of it is quite difficult and much will be held over to next time. * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (162 commits) selftests: vm: add tests for lock on fault mm: mlock: add mlock flags to enable VM_LOCKONFAULT usage mm: introduce VM_LOCKONFAULT mm: mlock: add new mlock system call mm: mlock: refactor mlock, munlock, and munlockall code kasan: always taint kernel on report mm, slub, kasan: enable user tracking by default with KASAN=y kasan: use IS_ALIGNED in memory_is_poisoned_8() kasan: Fix a type conversion error lib: test_kasan: add some testcases kasan: update reference to kasan prototype repo kasan: move KASAN_SANITIZE in arch/x86/boot/Makefile kasan: various fixes in documentation kasan: update log messages kasan: accurately determine the type of the bad access kasan: update reported bug types for kernel memory accesses kasan: update reported bug types for not user nor kernel memory accesses mm/kasan: prevent deadlock in kasan reporting mm/kasan: don't use kasan shadow pointer in generic functions mm/kasan: MODULE_VADDR is not available on all archs ...
| * | memcg: punt high overage reclaim to return-to-userland pathTejun Heo2015-11-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, try_charge() tries to reclaim memory synchronously when the high limit is breached; however, if the allocation doesn't have __GFP_WAIT, synchronous reclaim is skipped. If a process performs only speculative allocations, it can blow way past the high limit. This is actually easily reproducible by simply doing "find /". slab/slub allocator tries speculative allocations first, so as long as there's memory which can be consumed without blocking, it can keep allocating memory regardless of the high limit. This patch makes try_charge() always punt the over-high reclaim to the return-to-userland path. If try_charge() detects that high limit is breached, it adds the overage to current->memcg_nr_pages_over_high and schedules execution of mem_cgroup_handle_over_high() which performs synchronous reclaim from the return-to-userland path. As long as kernel doesn't have a run-away allocation spree, this should provide enough protection while making kmemcg behave more consistently. It also has the following benefits. - All over-high reclaims can use GFP_KERNEL regardless of the specific gfp mask in use, e.g. GFP_NOFS, when the limit was breached. - It copes with prio inversion. Previously, a low-prio task with small memory.high might perform over-high reclaim with a bunch of locks held. If a higher prio task needed any of these locks, it would have to wait until the low prio task finished reclaim and released the locks. By handing over-high reclaim to the task exit path this issue can be avoided. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@kernel.org> Reviewed-by: Vladimir Davydov <vdavydov@parallels.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | memcg: flatten task_struct->memcg_oomTejun Heo2015-11-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | task_struct->memcg_oom is a sub-struct containing fields which are used for async memcg oom handling. Most task_struct fields aren't packaged this way and it can lead to unnecessary alignment paddings. This patch flattens it. * task.memcg_oom.memcg -> task.memcg_in_oom * task.memcg_oom.gfp_mask -> task.memcg_oom_gfp_mask * task.memcg_oom.order -> task.memcg_oom_order * task.memcg_oom.may_oom -> task.memcg_may_oom In addition, task.memcg_may_oom is relocated to where other bitfields are which reduces the size of task_struct. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Vladimir Davydov <vdavydov@parallels.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | kernel/watchdog.c: add sysctl knob hardlockup_panicDon Zickus2015-11-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The only way to enable a hardlockup to panic the machine is to set 'nmi_watchdog=panic' on the kernel command line. This makes it awkward for end users and folks who want to run automate tests (like myself). Mimic the softlockup_panic knob and create a /proc/sys/kernel/hardlockup_panic knob. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ulrich Obergfell <uobergfe@redhat.com> Acked-by: Jiri Kosina <jkosina@suse.cz> Reviewed-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Merge branch 'for-4.4' of ↵Linus Torvalds2015-11-05
|\ \ \ | |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "The cgroup core saw several significant updates this cycle: - percpu_rwsem for threadgroup locking is reinstated. This was temporarily dropped due to down_write latency issues. Oleg's rework of percpu_rwsem which is scheduled to be merged in this merge window resolves the issue. - On the v2 hierarchy, when controllers are enabled and disabled, all operations are atomic and can fail and revert cleanly. This allows ->can_attach() failure which is necessary for cpu RT slices. - Tasks now stay associated with the original cgroups after exit until released. This allows tracking resources held by zombies (e.g. pids) and makes it easy to find out where zombies came from on the v2 hierarchy. The pids controller was broken before these changes as zombies escaped the limits; unfortunately, updating this behavior required too many invasive changes and I don't think it's a good idea to backport them, so the pids controller on 4.3, the first version which included the pids controller, will stay broken at least until I'm sure about the cgroup core changes. - Optimization of a couple common tests using static_key" * 'for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (38 commits) cgroup: fix race condition around termination check in css_task_iter_next() blkcg: don't create "io.stat" on the root cgroup cgroup: drop cgroup__DEVEL__legacy_files_on_dfl cgroup: replace error handling in cgroup_init() with WARN_ON()s cgroup: add cgroup_subsys->free() method and use it to fix pids controller cgroup: keep zombies associated with their original cgroups cgroup: make css_set_rwsem a spinlock and rename it to css_set_lock cgroup: don't hold css_set_rwsem across css task iteration cgroup: reorganize css_task_iter functions cgroup: factor out css_set_move_task() cgroup: keep css_set and task lists in chronological order cgroup: make cgroup_destroy_locked() test cgroup_is_populated() cgroup: make css_sets pin the associated cgroups cgroup: relocate cgroup_[try]get/put() cgroup: move check_for_release() invocation cgroup: replace cgroup_has_tasks() with cgroup_is_populated() cgroup: make cgroup->nr_populated count the number of populated css_sets cgroup: remove an unused parameter from cgroup_task_migrate() cgroup: fix too early usage of static_branch_disable() cgroup: make cgroup_update_dfl_csses() migrate all target processes atomically ...
| * | sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsemTejun Heo2015-09-16
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Note: This commit was originally committed as d59cfc09c32a but got reverted by 0c986253b939 due to the performance regression from the percpu_rwsem write down/up operations added to cgroup task migration path. percpu_rwsem changes which alleviate the performance issue are pending for v4.4-rc1 merge window. Re-apply. The cgroup side of threadgroup locking uses signal_struct->group_rwsem to synchronize against threadgroup changes. This per-process rwsem adds small overhead to thread creation, exit and exec paths, forces cgroup code paths to do lock-verify-unlock-retry dance in a couple places and makes it impossible to atomically perform operations across multiple processes. This patch replaces signal_struct->group_rwsem with a global percpu_rwsem cgroup_threadgroup_rwsem which is cheaper on the reader side and contained in cgroups proper. This patch converts one-to-one. This does make writer side heavier and lower the granularity; however, cgroup process migration is a fairly cold path, we do want to optimize thread operations over it and cgroup migration operations don't take enough time for the lower granularity to matter. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/g/55F8097A.7000206@de.ibm.com Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds2015-11-04
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull networking updates from David Miller: Changes of note: 1) Allow to schedule ICMP packets in IPVS, from Alex Gartrell. 2) Provide FIB table ID in ipv4 route dumps just as ipv6 does, from David Ahern. 3) Allow the user to ask for the statistics to be filtered out of ipv4/ipv6 address netlink dumps. From Sowmini Varadhan. 4) More work to pass the network namespace context around deep into various packet path APIs, starting with the netfilter hooks. From Eric W Biederman. 5) Add layer 2 TX/RX checksum offloading to qeth driver, from Thomas Richter. 6) Use usec resolution for SYN/ACK RTTs in TCP, from Yuchung Cheng. 7) Support Very High Throughput in wireless MESH code, from Bob Copeland. 8) Allow setting the ageing_time in switchdev/rocker. From Scott Feldman. 9) Properly autoload L2TP type modules, from Stephen Hemminger. 10) Fix and enable offload features by default in 8139cp driver, from David Woodhouse. 11) Support both ipv4 and ipv6 sockets in a single vxlan device, from Jiri Benc. 12) Fix CWND limiting of thin streams in TCP, from Bendik Rønning Opstad. 13) Fix IPSEC flowcache overflows on large systems, from Steffen Klassert. 14) Convert bridging to track VLANs using rhashtable entries rather than a bitmap. From Nikolay Aleksandrov. 15) Make TCP listener handling completely lockless, this is a major accomplishment. Incoming request sockets now live in the established hash table just like any other socket too. From Eric Dumazet. 15) Provide more bridging attributes to netlink, from Nikolay Aleksandrov. 16) Use hash based algorithm for ipv4 multipath routing, this was very long overdue. From Peter Nørlund. 17) Several y2038 cures, mostly avoiding timespec. From Arnd Bergmann. 18) Allow non-root execution of EBPF programs, from Alexei Starovoitov. 19) Support SO_INCOMING_CPU as setsockopt, from Eric Dumazet. This influences the port binding selection logic used by SO_REUSEPORT. 20) Add ipv6 support to VRF, from David Ahern. 21) Add support for Mellanox Spectrum switch ASIC, from Jiri Pirko. 22) Add rtl8xxxu Realtek wireless driver, from Jes Sorensen. 23) Implement RACK loss recovery in TCP, from Yuchung Cheng. 24) Support multipath routes in MPLS, from Roopa Prabhu. 25) Fix POLLOUT notification for listening sockets in AF_UNIX, from Eric Dumazet. 26) Add new QED Qlogic river, from Yuval Mintz, Manish Chopra, and Sudarsana Kalluru. 27) Don't fetch timestamps on AF_UNIX sockets, from Hannes Frederic Sowa. 28) Support ipv6 geneve tunnels, from John W Linville. 29) Add flood control support to switchdev layer, from Ido Schimmel. 30) Fix CHECKSUM_PARTIAL handling of potentially fragmented frames, from Hannes Frederic Sowa. 31) Support persistent maps and progs in bpf, from Daniel Borkmann. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1790 commits) sh_eth: use DMA barriers switchdev: respect SKIP_EOPNOTSUPP flag in case there is no recursion net: sched: kill dead code in sch_choke.c irda: Delete an unnecessary check before the function call "irlmp_unregister_service" net: dsa: mv88e6xxx: include DSA ports in VLANs net: dsa: mv88e6xxx: disable SA learning for DSA and CPU ports net/core: fix for_each_netdev_feature vlan: Invoke driver vlan hooks only if device is present arcnet/com20020: add LEDS_CLASS dependency bpf, verifier: annotate verbose printer with __printf dp83640: Only wait for timestamps for packets with timestamping enabled. ptp: Change ptp_class to a proper bitmask dp83640: Prune rx timestamp list before reading from it dp83640: Delay scheduled work. dp83640: Include hash in timestamp/packet matching ipv6: fix tunnel error handling net/mlx5e: Fix LSO vlan insertion net/mlx5e: Re-eanble client vlan TX acceleration net/mlx5e: Return error in case mlx5e_set_features() fails net/mlx5e: Don't allow more than max supported channels ...
| * | bpf: charge user for creation of BPF maps and programsAlexei Starovoitov2015-10-12
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | since eBPF programs and maps use kernel memory consider it 'locked' memory from user accounting point of view and charge it against RLIMIT_MEMLOCK limit. This limit is typically set to 64Kbytes by distros, so almost all bpf+tracing programs would need to increase it, since they use maps, but kernel charges maximum map size upfront. For example the hash map of 1024 elements will be charged as 64Kbyte. It's inconvenient for current users and changes current behavior for root, but probably worth doing to be consistent root vs non-root. Similar accounting logic is done by mmap of perf_event. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2015-11-03
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler changes from Ingo Molnar: "The main changes in this cycle were: - sched/fair load tracking fixes and cleanups (Byungchul Park) - Make load tracking frequency scale invariant (Dietmar Eggemann) - sched/deadline updates (Juri Lelli) - stop machine fixes, cleanups and enhancements for bugs triggered by CPU hotplug stress testing (Oleg Nesterov) - scheduler preemption code rework: remove PREEMPT_ACTIVE and related cleanups (Peter Zijlstra) - Rework the sched_info::run_delay code to fix races (Peter Zijlstra) - Optimize per entity utilization tracking (Peter Zijlstra) - ... misc other fixes, cleanups and smaller updates" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (57 commits) sched: Don't scan all-offline ->cpus_allowed twice if !CONFIG_CPUSETS sched: Move cpu_active() tests from stop_two_cpus() into migrate_swap_stop() sched: Start stopper early stop_machine: Kill cpu_stop_threads->setup() and cpu_stop_unpark() stop_machine: Kill smp_hotplug_thread->pre_unpark, introduce stop_machine_unpark() stop_machine: Change cpu_stop_queue_two_works() to rely on stopper->enabled stop_machine: Introduce __cpu_stop_queue_work() and cpu_stop_queue_two_works() stop_machine: Ensure that a queued callback will be called before cpu_stop_park() sched/x86: Fix typo in __switch_to() comments sched/core: Remove a parameter in the migrate_task_rq() function sched/core: Drop unlikely behind BUG_ON() sched/core: Fix task and run queue sched_info::run_delay inconsistencies sched/numa: Fix task_tick_fair() from disabling numa_balancing sched/core: Add preempt_count invariant check sched/core: More notrace annotations sched/core: Kill PREEMPT_ACTIVE sched/core, sched/x86: Kill thread_info::saved_preempt_count sched/core: Simplify preempt_count tests sched/core: Robustify preemption leak checks sched/core: Stop setting PREEMPT_ACTIVE ...
| * | sched/core: Create preempt_count invariantPeter Zijlstra2015-10-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Assuming units of PREEMPT_DISABLE_OFFSET for preempt_count() numbers. Now that TASK_DEAD no longer results in preempt_count() == 3 during scheduling, we will always call context_switch() with preempt_count() == 2. However, we don't always end up with preempt_count() == 2 in finish_task_switch() because new tasks get created with preempt_count() == 1. Create FORK_PREEMPT_COUNT and set it to 2 and use that in the right places. Note that we cannot use INIT_PREEMPT_COUNT as that serves another purpose (boot). After this, preempt_count() is invariant across the context switch, with exception of PREEMPT_ACTIVE. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | sched/core: Simplify INIT_PREEMPT_COUNTPeter Zijlstra2015-10-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As per the following commit: d86ee4809d03 ("sched: optimize cond_resched()") we need PREEMPT_ACTIVE to avoid cond_resched() from working before the scheduler is set up. However, keeping preemption disabled should do the same thing already, making the PREEMPT_ACTIVE part entirely redundant. The only complication is !PREEMPT_COUNT kernels, where PREEMPT_DISABLED ends up being 0. Instead we use an unconditional PREEMPT_OFFSET to set preempt_count() even on !PREEMPT_COUNT kernels. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | Merge branch 'sched/urgent' into sched/core, to pick up fixes before ↵Ingo Molnar2015-10-06
| |\| | | | | | | | | | | | | | | | applying new changes Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | sched/core: Make 'sched_domain_topology' declaration staticJuergen Gross2015-09-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 'sched_domain_topology' variable is only used within kernel/sched/core.c. Make it static. Signed-off-by: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1442918939-9907-1-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | sched/fair: Make utilization tracking CPU scale-invariantDietmar Eggemann2015-09-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Besides the existing frequency scale-invariance correction factor, apply CPU scale-invariance correction factor to utilization tracking to compensate for any differences in compute capacity. This could be due to micro-architectural differences (i.e. instructions per seconds) between cpus in HMP systems (e.g. big.LITTLE), and/or differences in the current maximum frequency supported by individual cpus in SMP systems. In the existing implementation utilization isn't comparable between cpus as it is relative to the capacity of each individual CPU. Each segment of the sched_avg.util_sum geometric series is now scaled by the CPU performance factor too so the sched_avg.util_avg of each sched entity will be invariant from the particular CPU of the HMP/SMP system on which the sched entity is scheduled. With this patch, the utilization of a CPU stays relative to the max CPU performance of the fastest CPU in the system. In contrast to utilization (sched_avg.util_sum), load (sched_avg.load_sum) should not be scaled by compute capacity. The utilization metric is based on running time which only makes sense when cpus are _not_ fully utilized (utilization cannot go beyond 100% even if more tasks are added), where load is runnable time which isn't limited by the capacity of the CPU and therefore is a better metric for overloaded scenarios. If we run two nice-0 busy loops on two cpus with different compute capacity their load should be similar since their compute demands are the same. We have to assume that the compute demand of any task running on a fully utilized CPU (no spare cycles = 100% utilization) is high and the same no matter of the compute capacity of its current CPU, hence we shouldn't scale load by CPU capacity. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/55CE7409.1000700@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | sched/fair: Make load tracking frequency scale-invariantDietmar Eggemann2015-09-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Apply frequency scaling correction factor to per-entity load tracking to make it frequency invariant. Currently, load appears bigger when the CPU is running slower which affects load-balancing decisions. Each segment of the sched_avg.load_sum geometric series is now scaled by the current frequency so that the sched_avg.load_avg of each sched entity will be invariant from frequency scaling. Moreover, cfs_rq.runnable_load_sum is scaled by the current frequency as well. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <Dietmar.Eggemann@arm.com> Cc: Juri Lelli <Juri.Lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: daniel.lezcano@linaro.org Cc: mturquette@baylibre.com Cc: pang.xunlei@zte.com.cn Cc: rjw@rjwysocki.net Cc: sgurrappadi@nvidia.com Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1439569394-11974-2-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds2015-11-03
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU changes from Ingo Molnar: "The main changes in this cycle were: - Improvements to expedited grace periods (Paul E McKenney) - Performance improvements to and locktorture tests for percpu-rwsem (Oleg Nesterov, Paul E McKenney) - Torture-test changes (Paul E McKenney, Davidlohr Bueso) - Documentation updates (Paul E McKenney) - Miscellaneous fixes (Paul E McKenney, Boqun Feng, Oleg Nesterov, Patrick Marlier)" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits) fs/writeback, rcu: Don't use list_entry_rcu() for pointer offsetting in bdi_split_work_to_wbs() rcu: Better hotplug handling for synchronize_sched_expedited() rcu: Enable stall warnings for synchronize_rcu_expedited() rcu: Add tasks to expedited stall-warning messages rcu: Add online/offline info to expedited stall warning message rcu: Consolidate expedited CPU selection rcu: Prepare for consolidating expedited CPU selection cpu: Remove try_get_online_cpus() rcu: Stop excluding CPU hotplug in synchronize_sched_expedited() rcu: Stop silencing lockdep false positive for expedited grace periods rcu: Switch synchronize_sched_expedited() to IPI locktorture: Fix module unwind when bad torture_type specified torture: Forgive non-plural arguments rcutorture: Fix unused-function warning for torturing_tasks() rcutorture: Fix module unwind when bad torture_type specified rcu_sync: Cleanup the CONFIG_PROVE_RCU checks locking/percpu-rwsem: Clean up the lockdep annotations in percpu_down_read() locking/percpu-rwsem: Fix the comments outdated by rcu_sync locking/percpu-rwsem: Make use of the rcu_sync infrastructure locking/percpu-rwsem: Make percpu_free_rwsem() after kzalloc() safe ...
| * \ \ Merge branch 'for-mingo' of ↵Ingo Molnar2015-10-19
| |\ \ \ | | |_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney: - Miscellaneous fixes. (Paul E. McKenney, Boqun Feng, Oleg Nesterov, Patrick Marlier) - Improvements to expedited grace periods. (Paul E. McKenney) - Performance improvements to and locktorture tests for percpu-rwsem. (Oleg Nesterov, Paul E. McKenney) - Torture-test changes. (Paul E. McKenney, Davidlohr Bueso) - Documentation updates. (Paul E. McKenney) Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | rcu: Use single-stage IPI algorithm for RCU expedited grace periodPaul E. McKenney2015-09-21
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current preemptible-RCU expedited grace-period algorithm invokes synchronize_sched_expedited() to enqueue all tasks currently running in a preemptible-RCU read-side critical section, then waits for all the ->blkd_tasks lists to drain. This works, but results in both an IPI and a double context switch even on CPUs that do not happen to be running in a preemptible RCU read-side critical section. This commit implements a new algorithm that causes less OS jitter. This new algorithm IPIs all online CPUs that are not idle (from an RCU perspective), but refrains from self-IPIs. If a CPU receiving this IPI is not in a preemptible RCU read-side critical section (or is just now exiting one), it pushes quiescence up the rcu_node tree, otherwise, it sets a flag that will be handled by the upcoming outermost rcu_read_unlock(), which will then push quiescence up the tree. The expedited grace period must of course wait on any pre-existing blocked readers, and newly blocked readers must be queued carefully based on the state of both the normal and the expedited grace periods. This new queueing approach also avoids the need to update boost state, courtesy of the fact that blocked tasks are no longer ever migrated to the root rcu_node structure. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* | | posix_cpu_timer: Reduce unnecessary sighand lock contentionJason Low2015-10-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It was found while running a database workload on large systems that significant time was spent trying to acquire the sighand lock. The issue was that whenever an itimer expired, many threads ended up simultaneously trying to send the signal. Most of the time, nothing happened after acquiring the sighand lock because another thread had just already sent the signal and updated the "next expire" time. The fastpath_timer_check() didn't help much since the "next expire" time was updated after the threads exit fastpath_timer_check(). This patch addresses this by having the thread_group_cputimer structure maintain a boolean to signify when a thread in the group is already checking for process wide timers, and adds extra logic in the fastpath to check the boolean. Signed-off-by: Jason Low <jason.low2@hp.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: George Spelvin <linux@horizon.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: hideaki.kimura@hpe.com Cc: terry.rudd@hpe.com Cc: scott.norton@hpe.com Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1444849677-29330-5-git-send-email-jason.low2@hp.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | posix_cpu_timer: Convert cputimer->running to boolJason Low2015-10-15
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the next patch in this series, a new field 'checking_timer' will be added to 'struct thread_group_cputimer'. Both this and the existing 'running' integer field are just used as boolean values. To save space in the structure, we can make both of these fields booleans. This is a preparatory patch to convert the existing running integer field to a boolean. Suggested-by: George Spelvin <linux@horizon.com> Signed-off-by: Jason Low <jason.low2@hp.com> Reviewed: George Spelvin <linux@horizon.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: hideaki.kimura@hpe.com Cc: terry.rudd@hpe.com Cc: scott.norton@hpe.com Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1444849677-29330-4-git-send-email-jason.low2@hp.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* / Revert "sched, cgroup: replace signal_struct->group_rwsem with a global ↵Tejun Heo2015-09-16
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | percpu_rwsem" This reverts commit d59cfc09c32a2ae31f1c3bc2983a0cd79afb3f14. d59cfc09c32a ("sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem") and b5ba75b5fc0e ("cgroup: simplify threadgroup locking") changed how cgroup synchronizes against task fork and exits so that it uses global percpu_rwsem instead of per-process rwsem; unfortunately, the write [un]lock paths of percpu_rwsem always involve synchronize_rcu_expedited() which turned out to be too expensive. Improvements for percpu_rwsem are scheduled to be merged in the coming v4.4-rc1 merge window which alleviates this issue. For now, revert the two commits to restore per-process rwsem. They will be re-applied for the v4.4-rc1 merge window. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/g/55F8097A.7000206@de.ibm.com Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: stable@vger.kernel.org # v4.2+
* mm: defer flush of writable TLB entriesMel Gorman2015-09-04
| | | | | | | | | | | | | | | | If a PTE is unmapped and it's dirty then it was writable recently. Due to deferred TLB flushing, it's best to assume a writable TLB cache entry exists. With that assumption, the TLB must be flushed before any IO can start or the page is freed to avoid lost writes or data corruption. This patch defers flushing of potentially writable TLBs as long as possible. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: send one IPI per CPU to TLB flush all entries after unmapping pagesMel Gorman2015-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | An IPI is sent to flush remote TLBs when a page is unmapped that was potentially accesssed by other CPUs. There are many circumstances where this happens but the obvious one is kswapd reclaiming pages belonging to a running process as kswapd and the task are likely running on separate CPUs. On small machines, this is not a significant problem but as machine gets larger with more cores and more memory, the cost of these IPIs can be high. This patch uses a simple structure that tracks CPUs that potentially have TLB entries for pages being unmapped. When the unmapping is complete, the full TLB is flushed on the assumption that a refill cost is lower than flushing individual entries. Architectures wishing to do this must give the following guarantee. If a clean page is unmapped and not immediately flushed, the architecture must guarantee that a write to that linear address from a CPU with a cached TLB entry will trap a page fault. This is essentially what the kernel already depends on but the window is much larger with this patch applied and is worth highlighting. The architecture should consider whether the cost of the full TLB flush is higher than sending an IPI to flush each individual entry. An additional architecture helper called flush_tlb_local is required. It's a trivial wrapper with some accounting in the x86 case. The impact of this patch depends on the workload as measuring any benefit requires both mapped pages co-located on the LRU and memory pressure. The case with the biggest impact is multiple processes reading mapped pages taken from the vm-scalability test suite. The test case uses NR_CPU readers of mapped files that consume 10*RAM. Linear mapped reader on a 4-node machine with 64G RAM and 48 CPUs 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 159.62 ( 0.00%) 120.68 ( 24.40%) Ops lru-file-mmap-read-time_range 30.59 ( 0.00%) 2.80 ( 90.85%) Ops lru-file-mmap-read-time_stddv 6.70 ( 0.00%) 0.64 ( 90.38%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 581.00 611.43 System 5804.93 4111.76 Elapsed 161.03 122.12 This is showing that the readers completed 24.40% faster with 29% less system CPU time. From vmstats, it is known that the vanilla kernel was interrupted roughly 900K times per second during the steady phase of the test and the patched kernel was interrupts 180K times per second. The impact is lower on a single socket machine. 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 25.33 ( 0.00%) 20.38 ( 19.54%) Ops lru-file-mmap-read-time_range 0.91 ( 0.00%) 1.44 (-58.24%) Ops lru-file-mmap-read-time_stddv 0.28 ( 0.00%) 0.47 (-65.34%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 58.09 57.64 System 111.82 76.56 Elapsed 27.29 22.55 It's still a noticeable improvement with vmstat showing interrupts went from roughly 500K per second to 45K per second. The patch will have no impact on workloads with no memory pressure or have relatively few mapped pages. It will have an unpredictable impact on the workload running on the CPU being flushed as it'll depend on how many TLB entries need to be refilled and how long that takes. Worst case, the TLB will be completely cleared of active entries when the target PFNs were not resident at all. [sasha.levin@oracle.com: trace tlb flush after disabling preemption in try_to_unmap_flush] Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2015-08-31
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "The biggest change in this cycle is the rewrite of the main SMP load balancing metric: the CPU load/utilization. The main goal was to make the metric more precise and more representative - see the changelog of this commit for the gory details: 9d89c257dfb9 ("sched/fair: Rewrite runnable load and utilization average tracking") It is done in a way that significantly reduces complexity of the code: 5 files changed, 249 insertions(+), 494 deletions(-) and the performance testing results are encouraging. Nevertheless we need to keep an eye on potential regressions, since this potentially affects every SMP workload in existence. This work comes from Yuyang Du. Other changes: - SCHED_DL updates. (Andrea Parri) - Simplify architecture callbacks by removing finish_arch_switch(). (Peter Zijlstra et al) - cputime accounting: guarantee stime + utime == rtime. (Peter Zijlstra) - optimize idle CPU wakeups some more - inspired by Facebook server loads. (Mike Galbraith) - stop_machine fixes and updates. (Oleg Nesterov) - Introduce the 'trace_sched_waking' tracepoint. (Peter Zijlstra) - sched/numa tweaks. (Srikar Dronamraju) - misc fixes and small cleanups" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits) sched/deadline: Fix comment in enqueue_task_dl() sched/deadline: Fix comment in push_dl_tasks() sched: Change the sched_class::set_cpus_allowed() calling context sched: Make sched_class::set_cpus_allowed() unconditional sched: Fix a race between __kthread_bind() and sched_setaffinity() sched: Ensure a task has a non-normalized vruntime when returning back to CFS sched/numa: Fix NUMA_DIRECT topology identification tile: Reorganize _switch_to() sched, sparc32: Update scheduler comments in copy_thread() sched: Remove finish_arch_switch() sched, tile: Remove finish_arch_switch sched, sh: Fold finish_arch_switch() into switch_to() sched, score: Remove finish_arch_switch() sched, avr32: Remove finish_arch_switch() sched, MIPS: Get rid of finish_arch_switch() sched, arm: Remove finish_arch_switch() sched/fair: Clean up load average references sched/fair: Provide runnable_load_avg back to cfs_rq sched/fair: Remove task and group entity load when they are dead sched/fair: Init cfs_rq's sched_entity load average ...
| * sched: Fix a race between __kthread_bind() and sched_setaffinity()Peter Zijlstra2015-08-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Because sched_setscheduler() checks p->flags & PF_NO_SETAFFINITY without locks, a caller might observe an old value and race with the set_cpus_allowed_ptr() call from __kthread_bind() and effectively undo it: __kthread_bind() do_set_cpus_allowed() <SYSCALL> sched_setaffinity() if (p->flags & PF_NO_SETAFFINITIY) set_cpus_allowed_ptr() p->flags |= PF_NO_SETAFFINITY Fix the bug by putting everything under the regular scheduler locks. This also closes a hole in the serialization of task_struct::{nr_,}cpus_allowed. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dedekind1@gmail.com Cc: juri.lelli@arm.com Cc: mgorman@suse.de Cc: riel@redhat.com Cc: rostedt@goodmis.org Link: http://lkml.kernel.org/r/20150515154833.545640346@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
generated by cgit v1.2.2 (git 2.25.0) at 2025-08-04 23:18:16 -0400