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* Merge LITMUS^RT staging (as of time of this commit).Christopher Kenna2012-09-29
|\ | | | | | | | | | | Conflicts: Makefile include/linux/sched.h
| * Feather-Trace: keep track of interrupt-related interference.Bjoern B. Brandenburg2012-01-30
| | | | | | | | | | | | | | Increment a processor-local counter whenever an interrupt is handled. This allows Feather-Trace to include a (truncated) counter and a flag to report interference from interrupts. This could be used to filter samples that were disturbed by interrupts.
| * Merge 'Linux v3.0' into LitmusAndrea Bastoni2011-08-27
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some notes: * Litmus^RT scheduling class is the topmost scheduling class (above stop_sched_class). * scheduler_ipi() function (e.g., in smp_reschedule_interrupt()) may increase IPI latencies. * Added path into schedule() to quickly re-evaluate scheduling decision without becoming preemptive again. This used to be a standard path before the removal of BKL. Conflicts: Makefile arch/arm/kernel/calls.S arch/arm/kernel/smp.c arch/x86/include/asm/unistd_32.h arch/x86/kernel/smp.c arch/x86/kernel/syscall_table_32.S include/linux/hrtimer.h kernel/printk.c kernel/sched.c kernel/sched_fair.c
| * | Implement proper remote preemption supportBjoern B. Brandenburg2010-11-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To date, Litmus has just hooked into the smp_send_reschedule() IPI handler and marked tasks as having to reschedule to implement remote preemptions. This was never particularly clean, but so far we got away with it. However, changes in the underlying Linux, and peculartities of the ARM code (interrupts enabled before context switch) break this naive approach. This patch introduces new state-machine based remote preemption support. By examining the local state before calling set_tsk_need_resched(), we avoid confusing the underlying Linux scheduler. Further, this patch avoids sending unncessary IPIs.
| * | Merge commit 'v2.6.36' into wip-merge-2.6.36Andrea Bastoni2010-10-23
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: Makefile arch/x86/include/asm/unistd_32.h arch/x86/kernel/syscall_table_32.S kernel/sched.c kernel/time/tick-sched.c Relevant API and functions changes (solved in this commit): - (API) .enqueue_task() (enqueue_task_litmus), dequeue_task() (dequeue_task_litmus), [litmus/sched_litmus.c] - (API) .select_task_rq() (select_task_rq_litmus) [litmus/sched_litmus.c] - (API) sysrq_dump_trace_buffer() and sysrq_handle_kill_rt_tasks() [litmus/sched_trace.c] - struct kfifo internal buffer name changed (buffer -> buf) [litmus/sched_trace.c] - add_wait_queue_exclusive_locked -> __add_wait_queue_tail_exclusive [litmus/fmlp.c] - syscall numbers for both x86_32 and x86_64
| * | | hrtimer: add init function to properly set hrtimer_start_on_info paramsAndrea Bastoni2010-10-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This helper function is also useful to remind us that if we use hrtimer_pull outside the scope of triggering remote releases, we need to take care of properly set the "state" field of hrtimer_start_on_info structure.
| * | | Make smp_send_pull_timers() optional.Bjoern B. Brandenburg2010-06-01
| | | | | | | | | | | | | | | | | | | | There is currently no need to implement this in ARM. So let's make it optional instead.
| * | | Merge branch 'master' into wip-merge-2.6.34Andrea Bastoni2010-05-29
| |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Simple merge between master and 2.6.34 with conflicts resolved. This commit does not compile, the following main problems are still unresolved: - spinlock -> raw_spinlock API changes - kfifo API changes - sched_class API changes Conflicts: Makefile arch/x86/include/asm/hw_irq.h arch/x86/include/asm/unistd_32.h arch/x86/kernel/syscall_table_32.S include/linux/hrtimer.h kernel/sched.c kernel/sched_fair.c
| | * | | [ported from 2008.3] Add hrtimer_start_on() APIAndrea Bastoni2010-05-29
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| | * | | [ported from 2008.3] Add send_pull_timers() support for x86_32 archAndrea Bastoni2010-05-29
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| | * | | [ported from 2008.3] Add File Descriptor Attached Shared Objects (FDSO) ↵Andrea Bastoni2010-05-29
| | | | | | | | | | | | | | | | | | | | infrastructure
| | * | | [ported from 2008.3] Add support for quantum alignmentAndrea Bastoni2010-05-29
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| | * | | [ported from 2008.3] Add complete_n() callAndrea Bastoni2010-05-29
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| | * | | [ported from 2008.3] Core LITMUS^RT infrastructureAndrea Bastoni2010-05-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Port 2008.3 Core LITMUS^RT infrastructure to Linux 2.6.32 litmus_sched_class implements 4 new methods: - prio_changed: void - switched_to: void - get_rr_interval: return infinity (i.e., 0) - select_task_rq: return current cpu
* | | | | net: new counter for tx_timeout errors in sysfsdavid decotigny2012-09-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds the /sys/class/net/DEV/queues/Q/tx_timeout attribute containing the total number of timeout events on the given queue. It is always available with CONFIG_SYSFS, independently of CONFIG_RPS/XPS. Credits to Stephen Hemminger for a preliminary version of this patch. Tested: without CONFIG_SYSFS (compilation only) with sysfs and without CONFIG_RPS & CONFIG_XPS with sysfs and without CONFIG_RPS with sysfs and without CONFIG_XPS with defaults Signed-off-by: David Decotigny <david.decotigny@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Conflicts: include/linux/netdevice.h Signed-off-by: Christopher Kenna <cjk@cs.unc.edu>
* | | | | Add exynos video header file.Christopher Kenna2012-09-28
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* | | | | Apply k4412 kernel from HardKernel for ODROID-X.Christopher Kenna2012-09-28
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* | | | | USB: add USB_VENDOR_AND_INTERFACE_INFO() macroGustavo Padovan2012-08-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit d81a5d1956731c453b85c141458d4ff5d6cc5366 upstream. A lot of Broadcom Bluetooth devices provides vendor specific interface class and we are getting flooded by patches adding new device support. This change will help us enable support for any other Broadcom with vendor specific device that arrives in the future. Only the product id changes for those devices, so this macro would be perfect for us: { USB_VENDOR_AND_INTERFACE_INFO(0x0a5c, 0xff, 0x01, 0x01) } Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk> Acked-by: Henrik Rydberg <rydberg@bitmath.se> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | ARM: pxa: remove irq_to_gpio from ezx-pcap driverArnd Bergmann2012-08-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 59ee93a528b94ef4e81a08db252b0326feff171f upstream. The irq_to_gpio function was removed from the pxa platform in linux-3.2, and this driver has been broken since. There is actually no in-tree user of this driver that adds this platform device, but the driver can and does get enabled on some platforms. Without this patch, building ezx_defconfig results in: drivers/mfd/ezx-pcap.c: In function 'pcap_isr_work': drivers/mfd/ezx-pcap.c:205:2: error: implicit declaration of function 'irq_to_gpio' [-Werror=implicit-function-declaration] Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> Cc: Samuel Ortiz <sameo@linux.intel.com> Cc: Daniel Ribeiro <drwyrm@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | random: remove rand_initialize_irq()Theodore Ts'o2012-08-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit c5857ccf293968348e5eb4ebedc68074de3dcda6 upstream. With the new interrupt sampling system, we are no longer using the timer_rand_state structure in the irq descriptor, so we can stop initializing it now. [ Merged in fixes from Sedat to find some last missing references to rand_initialize_irq() ] Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | random: add new get_random_bytes_arch() functionTheodore Ts'o2012-08-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit c2557a303ab6712bb6e09447df828c557c710ac9 upstream. Create a new function, get_random_bytes_arch() which will use the architecture-specific hardware random number generator if it is present. Change get_random_bytes() to not use the HW RNG, even if it is avaiable. The reason for this is that the hw random number generator is fast (if it is present), but it requires that we trust the hardware manufacturer to have not put in a back door. (For example, an increasing counter encrypted by an AES key known to the NSA.) It's unlikely that Intel (for example) was paid off by the US Government to do this, but it's impossible for them to prove otherwise --- especially since Bull Mountain is documented to use AES as a whitener. Hence, the output of an evil, trojan-horse version of RDRAND is statistically indistinguishable from an RDRAND implemented to the specifications claimed by Intel. Short of using a tunnelling electronic microscope to reverse engineer an Ivy Bridge chip and disassembling and analyzing the CPU microcode, there's no way for us to tell for sure. Since users of get_random_bytes() in the Linux kernel need to be able to support hardware systems where the HW RNG is not present, most time-sensitive users of this interface have already created their own cryptographic RNG interface which uses get_random_bytes() as a seed. So it's much better to use the HW RNG to improve the existing random number generator, by mixing in any entropy returned by the HW RNG into /dev/random's entropy pool, but to always _use_ /dev/random's entropy pool. This way we get almost of the benefits of the HW RNG without any potential liabilities. The only benefits we forgo is the speed/performance enhancements --- and generic kernel code can't depend on depend on get_random_bytes() having the speed of a HW RNG anyway. For those places that really want access to the arch-specific HW RNG, if it is available, we provide get_random_bytes_arch(). Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | random: create add_device_randomness() interfaceLinus Torvalds2012-08-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit a2080a67abe9e314f9e9c2cc3a4a176e8a8f8793 upstream. Add a new interface, add_device_randomness() for adding data to the random pool that is likely to differ between two devices (or possibly even per boot). This would be things like MAC addresses or serial numbers, or the read-out of the RTC. This does *not* add any actual entropy to the pool, but it initializes the pool to different values for devices that might otherwise be identical and have very little entropy available to them (particularly common in the embedded world). [ Modified by tytso to mix in a timestamp, since there may be some variability caused by the time needed to detect/configure the hardware in question. ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | random: make 'add_interrupt_randomness()' do something saneTheodore Ts'o2012-08-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 775f4b297b780601e61787b766f306ed3e1d23eb upstream. We've been moving away from add_interrupt_randomness() for various reasons: it's too expensive to do on every interrupt, and flooding the CPU with interrupts could theoretically cause bogus floods of entropy from a somewhat externally controllable source. This solves both problems by limiting the actual randomness addition to just once a second or after 64 interrupts, whicever comes first. During that time, the interrupt cycle data is buffered up in a per-cpu pool. Also, we make sure the the nonblocking pool used by urandom is initialized before we start feeding the normal input pool. This assures that /dev/urandom is returning unpredictable data as soon as possible. (Based on an original patch by Linus, but significantly modified by tytso.) Tested-by: Eric Wustrow <ewust@umich.edu> Reported-by: Eric Wustrow <ewust@umich.edu> Reported-by: Nadia Heninger <nadiah@cs.ucsd.edu> Reported-by: Zakir Durumeric <zakir@umich.edu> Reported-by: J. Alex Halderman <jhalderm@umich.edu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | random: Add support for architectural random hooksH. Peter Anvin2012-08-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 63d77173266c1791f1553e9e8ccea65dc87c4485 upstream. Add support for architecture-specific hooks into the kernel-directed random number generator interfaces. This patchset does not use the architecture random number generator interfaces for the userspace-directed interfaces (/dev/random and /dev/urandom), thus eliminating the need to distinguish between them based on a pool pointer. Changes in version 3: - Moved the hooks from extract_entropy() to get_random_bytes(). - Changes the hooks to inlines. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Matt Mackall <mpm@selenic.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | workqueue: perform cpu down operations from low priority cpu_notifier()Tejun Heo2012-08-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 6575820221f7a4dd6eadecf7bf83cdd154335eda upstream. Currently, all workqueue cpu hotplug operations run off CPU_PRI_WORKQUEUE which is higher than normal notifiers. This is to ensure that workqueue is up and running while bringing up a CPU before other notifiers try to use workqueue on the CPU. Per-cpu workqueues are supposed to remain working and bound to the CPU for normal CPU_DOWN_PREPARE notifiers. This holds mostly true even with workqueue offlining running with higher priority because workqueue CPU_DOWN_PREPARE only creates a bound trustee thread which runs the per-cpu workqueue without concurrency management without explicitly detaching the existing workers. However, if the trustee needs to create new workers, it creates unbound workers which may wander off to other CPUs while CPU_DOWN_PREPARE notifiers are in progress. Furthermore, if the CPU down is cancelled, the per-CPU workqueue may end up with workers which aren't bound to the CPU. While reliably reproducible with a convoluted artificial test-case involving scheduling and flushing CPU burning work items from CPU down notifiers, this isn't very likely to happen in the wild, and, even when it happens, the effects are likely to be hidden by the following successful CPU down. Fix it by using different priorities for up and down notifiers - high priority for up operations and low priority for down operations. Workqueue cpu hotplug operations will soon go through further cleanup. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | cpuset: mm: reduce large amounts of memory barrier related damage v3Mel Gorman2012-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit cc9a6c8776615f9c194ccf0b63a0aa5628235545 upstream. Stable note: Not tracked in Bugzilla. [get|put]_mems_allowed() is extremely expensive and severely impacted page allocator performance. This is part of a series of patches that reduce page allocator overhead. Commit c0ff7453bb5c ("cpuset,mm: fix no node to alloc memory when changing cpuset's mems") wins a super prize for the largest number of memory barriers entered into fast paths for one commit. [get|put]_mems_allowed is incredibly heavy with pairs of full memory barriers inserted into a number of hot paths. This was detected while investigating at large page allocator slowdown introduced some time after 2.6.32. The largest portion of this overhead was shown by oprofile to be at an mfence introduced by this commit into the page allocator hot path. For extra style points, the commit introduced the use of yield() in an implementation of what looks like a spinning mutex. This patch replaces the full memory barriers on both read and write sides with a sequence counter with just read barriers on the fast path side. This is much cheaper on some architectures, including x86. The main bulk of the patch is the retry logic if the nodemask changes in a manner that can cause a false failure. While updating the nodemask, a check is made to see if a false failure is a risk. If it is, the sequence number gets bumped and parallel allocators will briefly stall while the nodemask update takes place. In a page fault test microbenchmark, oprofile samples from __alloc_pages_nodemask went from 4.53% of all samples to 1.15%. The actual results were 3.3.0-rc3 3.3.0-rc3 rc3-vanilla nobarrier-v2r1 Clients 1 UserTime 0.07 ( 0.00%) 0.08 (-14.19%) Clients 2 UserTime 0.07 ( 0.00%) 0.07 ( 2.72%) Clients 4 UserTime 0.08 ( 0.00%) 0.07 ( 3.29%) Clients 1 SysTime 0.70 ( 0.00%) 0.65 ( 6.65%) Clients 2 SysTime 0.85 ( 0.00%) 0.82 ( 3.65%) Clients 4 SysTime 1.41 ( 0.00%) 1.41 ( 0.32%) Clients 1 WallTime 0.77 ( 0.00%) 0.74 ( 4.19%) Clients 2 WallTime 0.47 ( 0.00%) 0.45 ( 3.73%) Clients 4 WallTime 0.38 ( 0.00%) 0.37 ( 1.58%) Clients 1 Flt/sec/cpu 497620.28 ( 0.00%) 520294.53 ( 4.56%) Clients 2 Flt/sec/cpu 414639.05 ( 0.00%) 429882.01 ( 3.68%) Clients 4 Flt/sec/cpu 257959.16 ( 0.00%) 258761.48 ( 0.31%) Clients 1 Flt/sec 495161.39 ( 0.00%) 517292.87 ( 4.47%) Clients 2 Flt/sec 820325.95 ( 0.00%) 850289.77 ( 3.65%) Clients 4 Flt/sec 1020068.93 ( 0.00%) 1022674.06 ( 0.26%) MMTests Statistics: duration Sys Time Running Test (seconds) 135.68 132.17 User+Sys Time Running Test (seconds) 164.2 160.13 Total Elapsed Time (seconds) 123.46 120.87 The overall improvement is small but the System CPU time is much improved and roughly in correlation to what oprofile reported (these performance figures are without profiling so skew is expected). The actual number of page faults is noticeably improved. For benchmarks like kernel builds, the overall benefit is marginal but the system CPU time is slightly reduced. To test the actual bug the commit fixed I opened two terminals. The first ran within a cpuset and continually ran a small program that faulted 100M of anonymous data. In a second window, the nodemask of the cpuset was continually randomised in a loop. Without the commit, the program would fail every so often (usually within 10 seconds) and obviously with the commit everything worked fine. With this patch applied, it also worked fine so the fix should be functionally equivalent. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Miao Xie <miaox@cn.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | mm: compaction: introduce sync-light migration for use by compactionMel Gorman2012-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit a6bc32b899223a877f595ef9ddc1e89ead5072b8 upstream. Stable note: Not tracked in Buzilla. This was part of a series that reduced interactivity stalls experienced when THP was enabled. These stalls were particularly noticable when copying data to a USB stick but the experiences for users varied a lot. This patch adds a lightweight sync migrate operation MIGRATE_SYNC_LIGHT mode that avoids writing back pages to backing storage. Async compaction maps to MIGRATE_ASYNC while sync compaction maps to MIGRATE_SYNC_LIGHT. For other migrate_pages users such as memory hotplug, MIGRATE_SYNC is used. This avoids sync compaction stalling for an excessive length of time, particularly when copying files to a USB stick where there might be a large number of dirty pages backed by a filesystem that does not support ->writepages. [aarcange@redhat.com: This patch is heavily based on Andrea's work] [akpm@linux-foundation.org: fix fs/nfs/write.c build] [akpm@linux-foundation.org: fix fs/btrfs/disk-io.c build] Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | mm: compaction: make isolate_lru_page() filter-aware againMel Gorman2012-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit c82449352854ff09e43062246af86bdeb628f0c3 upstream. Stable note: Not tracked in Bugzilla. A fix aimed at preserving page aging information by reducing LRU list churning had the side-effect of reducing THP allocation success rates. This was part of a series to restore the success rates while preserving the reclaim fix. Commit 39deaf85 ("mm: compaction: make isolate_lru_page() filter-aware") noted that compaction does not migrate dirty or writeback pages and that is was meaningless to pick the page and re-add it to the LRU list. This had to be partially reverted because some dirty pages can be migrated by compaction without blocking. This patch updates "mm: compaction: make isolate_lru_page" by skipping over pages that migration has no possibility of migrating to minimise LRU disruption. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel<riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | mm: compaction: determine if dirty pages can be migrated without blocking ↵Mel Gorman2012-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | within ->migratepage commit b969c4ab9f182a6e1b2a0848be349f99714947b0 upstream. Stable note: Not tracked in Bugzilla. A fix aimed at preserving page aging information by reducing LRU list churning had the side-effect of reducing THP allocation success rates. This was part of a series to restore the success rates while preserving the reclaim fix. Asynchronous compaction is used when allocating transparent hugepages to avoid blocking for long periods of time. Due to reports of stalling, there was a debate on disabling synchronous compaction but this severely impacted allocation success rates. Part of the reason was that many dirty pages are skipped in asynchronous compaction by the following check; if (PageDirty(page) && !sync && mapping->a_ops->migratepage != migrate_page) rc = -EBUSY; This skips over all mapping aops using buffer_migrate_page() even though it is possible to migrate some of these pages without blocking. This patch updates the ->migratepage callback with a "sync" parameter. It is the responsibility of the callback to fail gracefully if migration would block. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | mm: zone_reclaim: make isolate_lru_page() filter-awareMinchan Kim2012-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit f80c0673610e36ae29d63e3297175e22f70dde5f upstream. Stable note: Not tracked in Bugzilla. THP and compaction disrupt the LRU list leading to poor reclaim decisions which has a variable performance impact. In __zone_reclaim case, we don't want to shrink mapped page. Nonetheless, we have isolated mapped page and re-add it into LRU's head. It's unnecessary CPU overhead and makes LRU churning. Of course, when we isolate the page, the page might be mapped but when we try to migrate the page, the page would be not mapped. So it could be migrated. But race is rare and although it happens, it's no big deal. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | mm: compaction: make isolate_lru_page() filter-awareMinchan Kim2012-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 39deaf8585152f1a35c1676d3d7dc6ae0fb65967 upstream. Stable note: Not tracked in Bugzilla. THP and compaction disrupt the LRU list leading to poor reclaim decisions which has a variable performance impact. In async mode, compaction doesn't migrate dirty or writeback pages. So, it's meaningless to pick the page and re-add it to lru list. Of course, when we isolate the page in compaction, the page might be dirty or writeback but when we try to migrate the page, the page would be not dirty, writeback. So it could be migrated. But it's very unlikely as isolate and migration cycle is much faster than writeout. So, this patch helps cpu overhead and prevent unnecessary LRU churning. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | mm: change isolate mode from #define to bitwise typeMinchan Kim2012-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 4356f21d09283dc6d39a6f7287a65ddab61e2808 upstream. Stable note: Not tracked in Bugzilla. This patch makes later patches easier to apply but has no other impact. Change ISOLATE_XXX macro with bitwise isolate_mode_t type. Normally, macro isn't recommended as it's type-unsafe and making debugging harder as symbol cannot be passed throught to the debugger. Quote from Johannes " Hmm, it would probably be cleaner to fully convert the isolation mode into independent flags. INACTIVE, ACTIVE, BOTH is currently a tri-state among flags, which is a bit ugly." This patch moves isolate mode from swap.h to mmzone.h by memcontrol.h Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | timekeeping: Provide hrtimer update functionThomas Gleixner2012-07-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a backport of f6c06abfb3972ad4914cef57d8348fcb2932bc3b To finally fix the infamous leap second issue and other race windows caused by functions which change the offsets between the various time bases (CLOCK_MONOTONIC, CLOCK_REALTIME and CLOCK_BOOTTIME) we need a function which atomically gets the current monotonic time and updates the offsets of CLOCK_REALTIME and CLOCK_BOOTTIME with minimalistic overhead. The previous patch which provides ktime_t offsets allows us to make this function almost as cheap as ktime_get() which is going to be replaced in hrtimer_interrupt(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: John Stultz <johnstul@us.ibm.com> Link: http://lkml.kernel.org/r/1341960205-56738-7-git-send-email-johnstul@us.ibm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | hrtimer: Provide clock_was_set_delayed()John Stultz2012-07-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a backport of f55a6faa384304c89cfef162768e88374d3312cb clock_was_set() cannot be called from hard interrupt context because it calls on_each_cpu(). For fixing the widely reported leap seconds issue it is necessary to call it from hard interrupt context, i.e. the timer tick code, which does the timekeeping updates. Provide a new function which denotes it in the hrtimer cpu base structure of the cpu on which it is called and raise the hrtimer softirq. We then execute the clock_was_set() notificiation from softirq context in run_hrtimer_softirq(). The hrtimer softirq is rarely used, so polling the flag there is not a performance issue. [ tglx: Made it depend on CONFIG_HIGH_RES_TIMERS. We really should get rid of all this ifdeffery ASAP ] Signed-off-by: John Stultz <johnstul@us.ibm.com> Reported-by: Jan Engelhardt <jengelh@inai.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1341960205-56738-2-git-send-email-johnstul@us.ibm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | ntp: Fix leap-second hrtimer livelockJohn Stultz2012-07-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a backport of 6b43ae8a619d17c4935c3320d2ef9e92bdeed05d This should have been backported when it was commited, but I mistook the problem as requiring the ntp_lock changes that landed in 3.4 in order for it to occur. Unfortunately the same issue can happen (with only one cpu) as follows: do_adjtimex() write_seqlock_irq(&xtime_lock); process_adjtimex_modes() process_adj_status() ntp_start_leap_timer() hrtimer_start() hrtimer_reprogram() tick_program_event() clockevents_program_event() ktime_get() seq = req_seqbegin(xtime_lock); [DEADLOCK] This deadlock will no always occur, as it requires the leap_timer to force a hrtimer_reprogram which only happens if its set and there's no sooner timer to expire. NOTE: This patch, being faithful to the original commit, introduces a bug (we don't update wall_to_monotonic), which will be resovled by backporting a following fix. Original commit message below: Since commit 7dffa3c673fbcf835cd7be80bb4aec8ad3f51168 the ntp subsystem has used an hrtimer for triggering the leapsecond adjustment. However, this can cause a potential livelock. Thomas diagnosed this as the following pattern: CPU 0 CPU 1 do_adjtimex() spin_lock_irq(&ntp_lock); process_adjtimex_modes(); timer_interrupt() process_adj_status(); do_timer() ntp_start_leap_timer(); write_lock(&xtime_lock); hrtimer_start(); update_wall_time(); hrtimer_reprogram(); ntp_tick_length() tick_program_event() spin_lock(&ntp_lock); clockevents_program_event() ktime_get() seq = req_seqbegin(xtime_lock); This patch tries to avoid the problem by reverting back to not using an hrtimer to inject leapseconds, and instead we handle the leapsecond processing in the second_overflow() function. The downside to this change is that on systems that support highres timers, the leap second processing will occur on a HZ tick boundary, (ie: ~1-10ms, depending on HZ) after the leap second instead of possibly sooner (~34us in my tests w/ x86_64 lapic). This patch applies on top of tip/timers/core. CC: Sasha Levin <levinsasha928@gmail.com> CC: Thomas Gleixner <tglx@linutronix.de> Reported-by: Sasha Levin <levinsasha928@gmail.com> Diagnoised-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Sasha Levin <levinsasha928@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | memory hotplug: fix invalid memory access caused by stale kswapd pointerJiang Liu2012-07-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit d8adde17e5f858427504725218c56aef90e90fc7 upstream. kswapd_stop() is called to destroy the kswapd work thread when all memory of a NUMA node has been offlined. But kswapd_stop() only terminates the work thread without resetting NODE_DATA(nid)->kswapd to NULL. The stale pointer will prevent kswapd_run() from creating a new work thread when adding memory to the memory-less NUMA node again. Eventually the stale pointer may cause invalid memory access. An example stack dump as below. It's reproduced with 2.6.32, but latest kernel has the same issue. BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff81051a94>] exit_creds+0x12/0x78 PGD 0 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/system/memory/memory391/state CPU 11 Modules linked in: cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq microcode fuse loop dm_mod tpm_tis rtc_cmos i2c_i801 rtc_core tpm serio_raw pcspkr sg tpm_bios igb i2c_core iTCO_wdt rtc_lib mptctl iTCO_vendor_support button dca bnx2 usbhid hid uhci_hcd ehci_hcd usbcore sd_mod crc_t10dif edd ext3 mbcache jbd fan ide_pci_generic ide_core ata_generic ata_piix libata thermal processor thermal_sys hwmon mptsas mptscsih mptbase scsi_transport_sas scsi_mod Pid: 7949, comm: sh Not tainted 2.6.32.12-qiuxishi-5-default #92 Tecal RH2285 RIP: 0010:exit_creds+0x12/0x78 RSP: 0018:ffff8806044f1d78 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff880604f22140 RCX: 0000000000019502 RDX: 0000000000000000 RSI: 0000000000000202 RDI: 0000000000000000 RBP: ffff880604f22150 R08: 0000000000000000 R09: ffffffff81a4dc10 R10: 00000000000032a0 R11: ffff880006202500 R12: 0000000000000000 R13: 0000000000c40000 R14: 0000000000008000 R15: 0000000000000001 FS: 00007fbc03d066f0(0000) GS:ffff8800282e0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 000000060f029000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process sh (pid: 7949, threadinfo ffff8806044f0000, task ffff880603d7c600) Stack: ffff880604f22140 ffffffff8103aac5 ffff880604f22140 ffffffff8104d21e ffff880006202500 0000000000008000 0000000000c38000 ffffffff810bd5b1 0000000000000000 ffff880603d7c600 00000000ffffdd29 0000000000000003 Call Trace: __put_task_struct+0x5d/0x97 kthread_stop+0x50/0x58 offline_pages+0x324/0x3da memory_block_change_state+0x179/0x1db store_mem_state+0x9e/0xbb sysfs_write_file+0xd0/0x107 vfs_write+0xad/0x169 sys_write+0x45/0x6e system_call_fastpath+0x16/0x1b Code: ff 4d 00 0f 94 c0 84 c0 74 08 48 89 ef e8 1f fd ff ff 5b 5d 31 c0 41 5c c3 53 48 8b 87 20 06 00 00 48 89 fb 48 8b bf 18 06 00 00 <8b> 00 48 c7 83 18 06 00 00 00 00 00 00 f0 ff 0f 0f 94 c0 84 c0 RIP exit_creds+0x12/0x78 RSP <ffff8806044f1d78> CR2: 0000000000000000 [akpm@linux-foundation.org: add pglist_data.kswapd locking comments] Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | PCI: EHCI: fix crash during suspend on ASUS computersAlan Stern2012-07-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit dbf0e4c7257f8d684ec1a3c919853464293de66e upstream. Quite a few ASUS computers experience a nasty problem, related to the EHCI controllers, when going into system suspend. It was observed that the problem didn't occur if the controllers were not put into the D3 power state before starting the suspend, and commit 151b61284776be2d6f02d48c23c3625678960b97 (USB: EHCI: fix crash during suspend on ASUS computers) was created to do this. It turned out this approach messed up other computers that didn't have the problem -- it prevented USB wakeup from working. Consequently commit c2fb8a3fa25513de8fedb38509b1f15a5bbee47b (USB: add NO_D3_DURING_SLEEP flag and revert 151b61284776be2) was merged; it reverted the earlier commit and added a whitelist of known good board names. Now we know the actual cause of the problem. Thanks to AceLan Kao for tracking it down. According to him, an engineer at ASUS explained that some of their BIOSes contain a bug that was added in an attempt to work around a problem in early versions of Windows. When the computer goes into S3 suspend, the BIOS tries to verify that the EHCI controllers were first quiesced by the OS. Nothing's wrong with this, but the BIOS does it by checking that the PCI COMMAND registers contain 0 without checking the controllers' power state. If the register isn't 0, the BIOS assumes the controller needs to be quiesced and tries to do so. This involves making various MMIO accesses to the controller, which don't work very well if the controller is already in D3. The end result is a system hang or memory corruption. Since the value in the PCI COMMAND register doesn't matter once the controller has been suspended, and since the value will be restored anyway when the controller is resumed, we can work around the BIOS bug simply by setting the register to 0 during system suspend. This patch (as1590) does so and also reverts the second commit mentioned above, which is now unnecessary. In theory we could do this for every PCI device. However to avoid introducing new problems, the patch restricts itself to EHCI host controllers. Finally the affected systems can suspend with USB wakeup working properly. Reference: https://bugzilla.kernel.org/show_bug.cgi?id=37632 Reference: https://bugzilla.kernel.org/show_bug.cgi?id=42728 Based-on-patch-by: AceLan Kao <acelan.kao@canonical.com> Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Dâniel Fraga <fragabr@gmail.com> Tested-by: Javier Marcet <jmarcet@gmail.com> Tested-by: Andrey Rahmatullin <wrar@wrar.name> Tested-by: Oleksij Rempel <bug-track@fisher-privat.net> Tested-by: Pavel Pisa <pisa@cmp.felk.cvut.cz> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | USB: add NO_D3_DURING_SLEEP flag and revert 151b61284776be2Alan Stern2012-06-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit c2fb8a3fa25513de8fedb38509b1f15a5bbee47b upstream. This patch (as1558) fixes a problem affecting several ASUS computers: The machine crashes or corrupts memory when going into suspend if the ehci-hcd driver is bound to any controllers. Users have been forced to unbind or unload ehci-hcd before putting their systems to sleep. After extensive testing, it was determined that the machines don't like going into suspend when any EHCI controllers are in the PCI D3 power state. Presumably this is a firmware bug, but there's nothing we can do about it except to avoid putting the controllers in D3 during system sleep. The patch adds a new flag to indicate whether the problem is present, and avoids changing the controller's power state if the flag is set. Runtime suspend is unaffected; this matters only for system suspend. However as a side effect, the controller will not respond to remote wakeup requests while the system is asleep. Hence USB wakeup is not functional -- but of course, this is already true in the current state of affairs. A similar patch has already been applied as commit 151b61284776be2d6f02d48c23c3625678960b97 (USB: EHCI: fix crash during suspend on ASUS computers). The patch supersedes that one and reverts it. There are two differences: The old patch added the flag at the USB level; this patch adds it at the PCI level. The old patch applied to all chipsets with the same vendor, subsystem vendor, and product IDs; this patch makes an exception for a known-good system (based on DMI information). Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Dâniel Fraga <fragabr@gmail.com> Tested-by: Andrey Rahmatullin <wrar@wrar.name> Tested-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | skb: avoid unnecessary reallocations in __skb_cowFelix Fietkau2012-06-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 617c8c11236716dcbda877e764b7bf37c6fd8063 ] At the beginning of __skb_cow, headroom gets set to a minimum of NET_SKB_PAD. This causes unnecessary reallocations if the buffer was not cloned and the headroom is just below NET_SKB_PAD, but still more than the amount requested by the caller. This was showing up frequently in my tests on VLAN tx, where vlan_insert_tag calls skb_cow_head(skb, VLAN_HLEN). Locally generated packets should have enough headroom, and for forward paths, we already have NET_SKB_PAD bytes of headroom, so we don't need to add any extra space here. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | Revert "net: maintain namespace isolation between vlan and real device"David S. Miller2012-06-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 59b9997baba5242997ddc7bd96b1391f5275a5a4 ] This reverts commit 8a83a00b0735190384a348156837918271034144. It causes regressions for S390 devices, because it does an unconditional DST drop on SKBs for vlans and the QETH device needs the neighbour entry hung off the DST for certain things on transmit. Arnd can't remember exactly why he even needed this change. Conflicts: drivers/net/macvlan.c net/8021q/vlan_dev.c net/core/dev.c Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | mmc: sdio: avoid spurious calls to interrupt handlersNicolas Pitre2012-06-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit bbbc4c4d8c5face097d695f9bf3a39647ba6b7e7 upstream. Commit 06e8935feb ("optimized SDIO IRQ handling for single irq") introduced some spurious calls to SDIO function interrupt handlers, such as when the SDIO IRQ thread is started, or the safety check performed upon a system resume. Let's add a flag to perform the optimization only when a real interrupt is signaled by the host driver and we know there is no point confirming it. Reported-by: Sujit Reddy Thumma <sthumma@codeaurora.org> Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Chris Ball <cjb@laptop.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | block: don't mark buffers beyond end of disk as mappedJeff Moyer2012-06-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 080399aaaf3531f5b8761ec0ac30ff98891e8686 upstream. Hi, We have a bug report open where a squashfs image mounted on ppc64 would exhibit errors due to trying to read beyond the end of the disk. It can easily be reproduced by doing the following: [root@ibm-p750e-02-lp3 ~]# ls -l install.img -rw-r--r-- 1 root root 142032896 Apr 30 16:46 install.img [root@ibm-p750e-02-lp3 ~]# mount -o loop ./install.img /mnt/test [root@ibm-p750e-02-lp3 ~]# dd if=/dev/loop0 of=/dev/null dd: reading `/dev/loop0': Input/output error 277376+0 records in 277376+0 records out 142016512 bytes (142 MB) copied, 0.9465 s, 150 MB/s In dmesg, you'll find the following: squashfs: version 4.0 (2009/01/31) Phillip Lougher [ 43.106012] attempt to access beyond end of device [ 43.106029] loop0: rw=0, want=277410, limit=277408 [ 43.106039] Buffer I/O error on device loop0, logical block 138704 [ 43.106053] attempt to access beyond end of device [ 43.106057] loop0: rw=0, want=277412, limit=277408 [ 43.106061] Buffer I/O error on device loop0, logical block 138705 [ 43.106066] attempt to access beyond end of device [ 43.106070] loop0: rw=0, want=277414, limit=277408 [ 43.106073] Buffer I/O error on device loop0, logical block 138706 [ 43.106078] attempt to access beyond end of device [ 43.106081] loop0: rw=0, want=277416, limit=277408 [ 43.106085] Buffer I/O error on device loop0, logical block 138707 [ 43.106089] attempt to access beyond end of device [ 43.106093] loop0: rw=0, want=277418, limit=277408 [ 43.106096] Buffer I/O error on device loop0, logical block 138708 [ 43.106101] attempt to access beyond end of device [ 43.106104] loop0: rw=0, want=277420, limit=277408 [ 43.106108] Buffer I/O error on device loop0, logical block 138709 [ 43.106112] attempt to access beyond end of device [ 43.106116] loop0: rw=0, want=277422, limit=277408 [ 43.106120] Buffer I/O error on device loop0, logical block 138710 [ 43.106124] attempt to access beyond end of device [ 43.106128] loop0: rw=0, want=277424, limit=277408 [ 43.106131] Buffer I/O error on device loop0, logical block 138711 [ 43.106135] attempt to access beyond end of device [ 43.106139] loop0: rw=0, want=277426, limit=277408 [ 43.106143] Buffer I/O error on device loop0, logical block 138712 [ 43.106147] attempt to access beyond end of device [ 43.106151] loop0: rw=0, want=277428, limit=277408 [ 43.106154] Buffer I/O error on device loop0, logical block 138713 [ 43.106158] attempt to access beyond end of device [ 43.106162] loop0: rw=0, want=277430, limit=277408 [ 43.106166] attempt to access beyond end of device [ 43.106169] loop0: rw=0, want=277432, limit=277408 ... [ 43.106307] attempt to access beyond end of device [ 43.106311] loop0: rw=0, want=277470, limit=2774 Squashfs manages to read in the end block(s) of the disk during the mount operation. Then, when dd reads the block device, it leads to block_read_full_page being called with buffers that are beyond end of disk, but are marked as mapped. Thus, it would end up submitting read I/O against them, resulting in the errors mentioned above. I fixed the problem by modifying init_page_buffers to only set the buffer mapped if it fell inside of i_size. Cheers, Jeff Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Nick Piggin <npiggin@kernel.dk> -- Changes from v1->v2: re-used max_block, as suggested by Nick Piggin. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | block: fix buffer overflow when printing partition UUIDsTejun Heo2012-06-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 05c69d298c96703741cac9a5cbbf6c53bd55a6e2 upstream. 6d1d8050b4bc8 "block, partition: add partition_meta_info to hd_struct" added part_unpack_uuid() which assumes that the passed in buffer has enough space for sprintfing "%pU" - 37 characters including '\0'. Unfortunately, b5af921ec0233 "init: add support for root devices specified by partition UUID" supplied 33 bytes buffer to the function leading to the following panic with stackprotector enabled. Kernel panic - not syncing: stack-protector: Kernel stack corrupted in: ffffffff81b14c7e [<ffffffff815e226b>] panic+0xba/0x1c6 [<ffffffff81b14c7e>] ? printk_all_partitions+0x259/0x26xb [<ffffffff810566bb>] __stack_chk_fail+0x1b/0x20 [<ffffffff81b15c7e>] printk_all_paritions+0x259/0x26xb [<ffffffff81aedfe0>] mount_block_root+0x1bc/0x27f [<ffffffff81aee0fa>] mount_root+0x57/0x5b [<ffffffff81aee23b>] prepare_namespace+0x13d/0x176 [<ffffffff8107eec0>] ? release_tgcred.isra.4+0x330/0x30 [<ffffffff81aedd60>] kernel_init+0x155/0x15a [<ffffffff81087b97>] ? schedule_tail+0x27/0xb0 [<ffffffff815f4d24>] kernel_thread_helper+0x5/0x10 [<ffffffff81aedc0b>] ? start_kernel+0x3c5/0x3c5 [<ffffffff815f4d20>] ? gs_change+0x13/0x13 Increase the buffer size, remove the dangerous part_unpack_uuid() and use snprintf() directly from printk_all_partitions(). Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Szymon Gruszczynski <sz.gruszczynski@googlemail.com> Cc: Will Drewry <wad@chromium.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | usbnet: fix skb traversing races during unlink(v2)Ming Lei2012-05-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 5b6e9bcdeb65634b4ad604eb4536404bbfc62cfa upstream. Commit 4231d47e6fe69f061f96c98c30eaf9fb4c14b96d(net/usbnet: avoid recursive locking in usbnet_stop()) fixes the recursive locking problem by releasing the skb queue lock before unlink, but may cause skb traversing races: - after URB is unlinked and the queue lock is released, the refered skb and skb->next may be moved to done queue, even be released - in skb_queue_walk_safe, the next skb is still obtained by next pointer of the last skb - so maybe trigger oops or other problems This patch extends the usage of entry->state to describe 'start_unlink' state, so always holding the queue(rx/tx) lock to change the state if the referd skb is in rx or tx queue because we need to know if the refered urb has been started unlinking in unlink_urbs. The other part of this patch is based on Huajun's patch: always traverse from head of the tx/rx queue to get skb which is to be unlinked but not been started unlinking. Signed-off-by: Huajun Li <huajun.li.lee@gmail.com> Signed-off-by: Ming Lei <tom.leiming@gmail.com> Cc: Oliver Neukum <oneukum@suse.de> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | Fix __read_seqcount_begin() to use ACCESS_ONCE for sequence value readLinus Torvalds2012-05-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 2f624278626677bfaf73fef97f86b37981621f5c upstream. We really need to use a ACCESS_ONCE() on the sequence value read in __read_seqcount_begin(), because otherwise the compiler might end up reloading the value in between the test and the return of it. As a result, it might end up returning an odd value (which means that a write is in progress). If the reader is then fast enough that that odd value is still the current one when the read_seqcount_retry() is done, we might end up with a "successful" read sequence, even despite the concurrent write being active. In practice this probably never really happens - there just isn't anything else going on around the read of the sequence count, and the common case is that we end up having a read barrier immediately afterwards. So the code sequence in which gcc might decide to reaload from memory is small, and there's no reason to believe it would ever actually do the reload. But if the compiler ever were to decide to do so, it would be incredibly annoying to debug. Let's just make sure. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | efi: Add new variable attributesMatthew Garrett2012-05-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 41b3254c93acc56adc3c4477fef7c9512d47659e upstream. More recent versions of the UEFI spec have added new attributes for variables. Add them. Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | pipes: add a "packetized pipe" mode for writingLinus Torvalds2012-05-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 9883035ae7edef3ec62ad215611cb8e17d6a1a5d upstream. The actual internal pipe implementation is already really about individual packets (called "pipe buffers"), and this simply exposes that as a special packetized mode. When we are in the packetized mode (marked by O_DIRECT as suggested by Alan Cox), a write() on a pipe will not merge the new data with previous writes, so each write will get a pipe buffer of its own. The pipe buffer is then marked with the PIPE_BUF_FLAG_PACKET flag, which in turn will tell the reader side to break the read at that boundary (and throw away any partial packet contents that do not fit in the read buffer). End result: as long as you do writes less than PIPE_BUF in size (so that the pipe doesn't have to split them up), you can now treat the pipe as a packet interface, where each read() system call will read one packet at a time. You can just use a sufficiently big read buffer (PIPE_BUF is sufficient, since bigger than that doesn't guarantee atomicity anyway), and the return value of the read() will naturally give you the size of the packet. NOTE! We do not support zero-sized packets, and zero-sized reads and writes to a pipe continue to be no-ops. Also note that big packets will currently be split at write time, but that the size at which that happens is not really specified (except that it's bigger than PIPE_BUF). Currently that limit is the system page size, but we might want to explicitly support bigger packets some day. The main user for this is going to be the autofs packet interface, allowing us to stop having to care so deeply about exact packet sizes (which have had bugs with 32/64-bit compatibility modes). But user space can create packetized pipes with "pipe2(fd, O_DIRECT)", which will fail with an EINVAL on kernels that do not support this interface. Tested-by: Michael Tokarev <mjt@tls.msk.ru> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: David Miller <davem@davemloft.net> Cc: Ian Kent <raven@themaw.net> Cc: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | USB: EHCI: fix crash during suspend on ASUS computersAlan Stern2012-05-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 151b61284776be2d6f02d48c23c3625678960b97 upstream. This patch (as1545) fixes a problem affecting several ASUS computers: The machine crashes or corrupts memory when going into suspend if the ehci-hcd driver is bound to any controllers. Users have been forced to unbind or unload ehci-hcd before putting their systems to sleep. After extensive testing, it was determined that the machines don't like going into suspend when any EHCI controllers are in the PCI D3 power state. Presumably this is a firmware bug, but there's nothing we can do about it except to avoid putting the controllers in D3 during system sleep. The patch adds a new flag to indicate whether the problem is present, and avoids changing the controller's power state if the flag is set. Runtime suspend is unaffected; this matters only for system suspend. However as a side effect, the controller will not respond to remote wakeup requests while the system is asleep. Hence USB wakeup is not functional -- but of course, this is already true in the current state of affairs. This fixes Bugzilla #42728. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Steven Rostedt <rostedt@goodmis.org> Tested-by: Andrey Rahmatullin <wrar@wrar.name> Tested-by: Oleksij Rempel (fishor) <bug-track@fisher-privat.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | KVM: unmap pages from the iommu when slots are removedAlex Williamson2012-05-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 32f6daad4651a748a58a3ab6da0611862175722f upstream. We've been adding new mappings, but not destroying old mappings. This can lead to a page leak as pages are pinned using get_user_pages, but only unpinned with put_page if they still exist in the memslots list on vm shutdown. A memslot that is destroyed while an iommu domain is enabled for the guest will therefore result in an elevated page reference count that is never cleared. Additionally, without this fix, the iommu is only programmed with the first translation for a gpa. This can result in peer-to-peer errors if a mapping is destroyed and replaced by a new mapping at the same gpa as the iommu will still be pointing to the original, pinned memory address. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | tcp: allow splice() to build full TSO packetsEric Dumazet2012-04-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ This combines upstream commit 2f53384424251c06038ae612e56231b96ab610ee and the follow-on bug fix commit 35f9c09fe9c72eb8ca2b8e89a593e1c151f28fc2 ] vmsplice()/splice(pipe, socket) call do_tcp_sendpages() one page at a time, adding at most 4096 bytes to an skb. (assuming PAGE_SIZE=4096) The call to tcp_push() at the end of do_tcp_sendpages() forces an immediate xmit when pipe is not already filled, and tso_fragment() try to split these skb to MSS multiples. 4096 bytes are usually split in a skb with 2 MSS, and a remaining sub-mss skb (assuming MTU=1500) This makes slow start suboptimal because many small frames are sent to qdisc/driver layers instead of big ones (constrained by cwnd and packets in flight of course) In fact, applications using sendmsg() (adding an additional memory copy) instead of vmsplice()/splice()/sendfile() are a bit faster because of this anomaly, especially if serving small files in environments with large initial [c]wnd. Call tcp_push() only if MSG_MORE is not set in the flags parameter. This bit is automatically provided by splice() internals but for the last page, or on all pages if user specified SPLICE_F_MORE splice() flag. In some workloads, this can reduce number of sent logical packets by an order of magnitude, making zero-copy TCP actually faster than one-copy :) Reported-by: Tom Herbert <therbert@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: Maciej Żenczykowski <maze@google.com> Cc: Mahesh Bandewar <maheshb@google.com> Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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