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* ceph: handle racing calls to ceph_init_dentrySage Weil2011-07-26
| | | | | | | | | | | | The ->lookup() and prepopulate_readdir() callers are working with unhashed dentries, so we don't have to worry. The export.c callers, though, need to initialize something they got back from d_obtain_alias() and are potentially racing with other callers. Make sure we don't return unless the dentry is properly initialized (by us or someone else). Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* ceph: set dir complete frag after adding capabilitySage Weil2011-07-26
| | | | | | | | | | Curretly ceph_add_cap clears the complete bit if we are newly issued the FILE_SHARED cap, which is normally the case for a newly issue cap on a new directory. That means we clear the just-set bit. Move the check that sets the flag to after the cap is added/updated. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* rbd: set blk_queue request sizes to object sizeJosh Durgin2011-07-26
| | | | | | | This improves performance since more requests can be merged. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Josh Durgin <josh.durgin@dreamhost.com>
* ceph: set up readahead size when rsize is not passedYehuda Sadeh2011-07-26
| | | | | | | This should improve the default read performance, as without it readahead is practically disabled. Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
* rbd: cancel watch request when releasing the deviceYehuda Sadeh2011-07-26
| | | | | | | | We were missing this cleanup, so when a device was released the osd didn't clean up its watchers list, so following notifications could be slow as osd needed to timeout on the client. Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
* ceph: ignore lease maskSage Weil2011-07-26
| | | | | | | | The lease mask is no longer used (and it changed a while back). Instead, use a non-zero duration to indicate that there is a lease being issued. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* ceph: fix ceph_lookup_open intent usageSage Weil2011-07-26
| | | | | | | | | | | | | | | We weren't properly calling lookup_instantiate_filp when setting up the lookup intent, which could lead to file leakage on errors. So: - use separate helper for the hidden snapdir translation, immediately following the mds request - use ceph_finish_lookup for the final dentry/return value dance in the exit path - lookup_instantiate_filp on success Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* ceph: only link open operations to directory unsafe list if O_CREAT|O_TRUNCSage Weil2011-07-26
| | | | | | | | We only need to put these on the directory unsafe list if they have side effects that fsync(2) should flush out. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* ceph: fix bad parent_inode calc in ceph_lookup_openSage Weil2011-07-26
| | | | | | | | | | | | | | We were always getting NULL here because the intent file f_dentry is always NULL at this point, which means we were always passing NULL to ceph_mdsc_do_request. In reality, this was fine, since this isn't currently ever a write operation that needs to get strung on the dir's unsafe list. Use the dir explicitly, and only pass it if this open has side-effects that a dir fsync should flush. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* ceph: avoid carrying Fw cap during write into page cacheSage Weil2011-07-26
| | | | | | | | | | The generic_file_aio_write call may block on balance_dirty_pages while we flush data to the OSDs. If we hold a reference to the FILE_WR cap during that interval revocation by the MDS (e.g., to do a stat(2)) may be very slow. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* libceph: don't time out osd requests that haven't been receivedSage Weil2011-07-26
| | | | | | | | | | | | Keep track of when an outgoing message is ACKed (i.e., the server fully received it and, presumably, queued it for processing). Time out OSD requests only if it's been too long since they've been received. This prevents timeouts and connection thrashing when the OSDs are simply busy and are throttling the requests they read off the network. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* ceph: report f_bfree based on kb_avail rather than diffing.Greg Farnum2011-07-26
| | | | | Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Greg Farnum <gregory.farnum@dreamhost.com>
* ceph: only queue capsnap if caps are dirtySage Weil2011-07-26
| | | | | | | | | | | | We used to go into this branch if i_wrbuffer_ref_head was non-zero. This was an ancient check from before we were careful about dealing with all kinds of caps (and not just dirty pages). It is cleaner to only queue a capsnap if there is an actual dirty cap. If we are racing with... something...we will end up here with ci->i_wrbuffer_refs but no dirty caps. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* ceph: fix snap writeback when racing with writesSage Weil2011-07-26
| | | | | | | | | | | | | | There are two problems that come up when we try to queue a capsnap while a write is in progress: - The FILE_WR cap is held, but not yet dirty, so we may queue a capsnap with dirty == 0. That will crash later in __ceph_flush_snaps(). Or on the FILE_WR cap if a write is in progress. - We may not have i_head_snapc set, which causes problems pretty quickly. Look to the snaprealm in this case. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* ceph: use flag bit for at_end readdir flagSage Weil2011-07-26
| | | | | | | This saves us a word of memory per file. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* ceph: add F_SYNC file flag to force sync (non-O_DIRECT) ioSage Weil2011-07-26
| | | | | | | | | | This allows us to force IO through the sync path which you normally only get when multiple clients are reading/writing to the same file or by mounting with -o sync. Among other things, this lets test programs verify correctness with a single mount. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* ceph: add flags field to file_infoSage Weil2011-07-26
| | | | | Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
* Linux 3.0Linus Torvalds2011-07-21
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* Merge branch 'for_linus' of ↵Linus Torvalds2011-07-21
|\ | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb * 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb: sparc,kgdbts: fix compile regression with kgdb test suite
| * sparc,kgdbts: fix compile regression with kgdb test suiteJason Wessel2011-07-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 63ab25ebbc (kgdbts: unify/generalize gdb breakpoint adjustment) introduced a compile regression on sparc. kgdbts.c: In function 'check_and_rewind_pc': kgdbts.c:307: error: implicit declaration of function 'instruction_pointer_set' Simply add the correct macro definition for instruction pointer on the Sparc architecture. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Acked-by: David S. Miller <davem@davemloft.net>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6Linus Torvalds2011-07-21
|\ \ | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6: CIFS: Fix wrong length in cifs_iovec_read
| * | CIFS: Fix wrong length in cifs_iovec_readPavel Shilovsky2011-07-20
| | | | | | | | | | | | | | | | | | Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
* | | Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds2011-07-21
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Make Dell Latitude E6420 use reboot=pci x86: Make Dell Latitude E5420 use reboot=pci
| * | | x86: Make Dell Latitude E6420 use reboot=pciH. Peter Anvin2011-07-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Yet another variant of the Dell Latitude series which requires reboot=pci. From the E5420 bug report by Daniel J Blueman: > The E6420 is affected also (same platform, different casing and > features), which provides an external confirmation of the issue; I can > submit a patch for that later or include it if you prefer: > http://linux.koolsolutions.com/2009/08/04/howto-fix-linux-hangfreeze-during-reboots-and-restarts/ Reported-by: Daniel J Blueman <daniel.blueman@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: <stable@kernel.org>
| * | | x86: Make Dell Latitude E5420 use reboot=pciDaniel J Blueman2011-07-21
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rebooting on the Dell E5420 often hangs with the keyboard or ACPI methods, but is reliable via the PCI method. [ hpa: this was deferred because we believed for a long time that the recent reshuffling of the boot priorities in commit 660e34cebf0a11d54f2d5dd8838607452355f321 fixed this platform. Unfortunately that turned out to be incorrect. ] Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com> Link: http://lkml.kernel.org/r/1305248699-2347-1-git-send-email-daniel.blueman@gmail.com Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: <stable@kernel.org>
* | | Merge branch 'drm-intel-fixes' of ↵Linus Torvalds2011-07-21
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/keithp/linux-2.6 * 'drm-intel-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/keithp/linux-2.6: drm/i915: Fix unfenced alignment on pre-G33 hardware drm/i915: Add quirk to disable SSC on Lenovo U160 LVDS
| * | | drm/i915: Fix unfenced alignment on pre-G33 hardwareChris Wilson2011-07-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Align unfenced buffers on older hardware to the power-of-two object size. The docs suggest that it should be possible to align only to a power-of-two tile height, but using the already computed fence size is easier and always correct. We also have to make sure that we unbind misaligned buffers upon tiling changes. In order to prevent a repetition of this bug, we change the interface to the alignment computation routines to force the caller to provide the requested alignment and size of the GTT binding rather than assume the current values on the object. Reported-and-tested-by: Sitosfe Wheeler <sitsofe@yahoo.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=36326 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: stable@kernel.org Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Keith Packard <keithp@keithp.com>
| * | | drm/i915: Add quirk to disable SSC on Lenovo U160 LVDSKeith Packard2011-07-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We've tried several times to make this machine 'just work', but every patch that does causes many other machines to fail. This adds a quirk which special cases this hardware and forces ssc to be disabled. There's no way to override this from the command line; that would be a significantly more invasive change. This patch fixes #36656 on fdo bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=36656 Signed-off-by: Keith Packard <keithp@keithp.com> References: https://bugs.freedesktop.org/show_bug.cgi?id=36656 Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
* | | | vfs: drop conditional inode prefetch in __do_lookup_rcuLinus Torvalds2011-07-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It seems to hurt performance in real life. Yes, the inode will be used later, but the conditional doesn't seem to predict all that well (negative dentries are not uncommon) and it looks like the cost of prefetching is simply higher than depending on the cache doing the right thing. As usual. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | FS-Cache: Fix __fscache_uncache_all_inode_pages()'s outer loopJan Beulich2011-07-21
| |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The compiler, at least for ix86 and m68k, validly warns that the comparison: next <= (loff_t)-1 is always true (and it's always true also for x86-64 and probably all other arches - as long as pgoff_t isn't wider than loff_t). The intention appears to be to avoid wrapping of "next", so rather than eliminating the pointless comparison, fix the loop to indeed get exited when "next" would otherwise wrap. On m68k the following warning is observed: fs/fscache/page.c: In function '__fscache_uncache_all_inode_pages': fs/fscache/page.c:979: warning: comparison is always false due to limited range of data type Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Reported-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Suresh Jayaraman <sjayaraman@suse.de> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds2011-07-20
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: signal: align __lock_task_sighand() irq disabling and RCU softirq,rcu: Inform RCU of irq_exit() activity sched: Add irq_{enter,exit}() to scheduler_ipi() rcu: protect __rcu_read_unlock() against scheduler-using irq handlers rcu: Streamline code produced by __rcu_read_unlock() rcu: Fix RCU_BOOST race handling current->rcu_read_unlock_special rcu: decrease rcu_report_exp_rnp coupling with scheduler
| * \ \ Merge branch 'rcu/urgent' of ↵Ingo Molnar2011-07-20
| |\ \ \ | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu into core/urgent
| | * | | signal: align __lock_task_sighand() irq disabling and RCUPaul E. McKenney2011-07-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The __lock_task_sighand() function calls rcu_read_lock() with interrupts and preemption enabled, but later calls rcu_read_unlock() with interrupts disabled. It is therefore possible that this RCU read-side critical section will be preempted and later RCU priority boosted, which means that rcu_read_unlock() will call rt_mutex_unlock() in order to deboost itself, but with interrupts disabled. This results in lockdep splats, so this commit nests the RCU read-side critical section within the interrupt-disabled region of code. This prevents the RCU read-side critical section from being preempted, and thus prevents the attempt to deboost with interrupts disabled. It is quite possible that a better long-term fix is to make rt_mutex_unlock() disable irqs when acquiring the rt_mutex structure's ->wait_lock. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | * | | softirq,rcu: Inform RCU of irq_exit() activityPeter Zijlstra2011-07-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcu_read_unlock_special() function relies on in_irq() to exclude scheduler activity from interrupt level. This fails because exit_irq() can invoke the scheduler after clearing the preempt_count() bits that in_irq() uses to determine that it is at interrupt level. This situation can result in failures as follows: $task IRQ SoftIRQ rcu_read_lock() /* do stuff */ <preempt> |= UNLOCK_BLOCKED rcu_read_unlock() --t->rcu_read_lock_nesting irq_enter(); /* do stuff, don't use RCU */ irq_exit(); sub_preempt_count(IRQ_EXIT_OFFSET); invoke_softirq() ttwu(); spin_lock_irq(&pi->lock) rcu_read_lock(); /* do stuff */ rcu_read_unlock(); rcu_read_unlock_special() rcu_report_exp_rnp() ttwu() spin_lock_irq(&pi->lock) /* deadlock */ rcu_read_unlock_special(t); Ed can simply trigger this 'easy' because invoke_softirq() immediately does a ttwu() of ksoftirqd/# instead of doing the in-place softirq stuff first, but even without that the above happens. Cure this by also excluding softirqs from the rcu_read_unlock_special() handler and ensuring the force_irqthreads ksoftirqd/# wakeup is done from full softirq context. [ Alternatively, delaying the ->rcu_read_lock_nesting decrement until after the special handling would make the thing more robust in the face of interrupts as well. And there is a separate patch for that. ] Cc: Thomas Gleixner <tglx@linutronix.de> Reported-and-tested-by: Ed Tomlinson <edt@aei.ca> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | * | | sched: Add irq_{enter,exit}() to scheduler_ipi()Peter Zijlstra2011-07-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ensure scheduler_ipi() calls irq_{enter,exit} when it does some actual work. Traditionally we never did any actual work from the resched IPI and all magic happened in the return from interrupt path. Now that we do do some work, we need to ensure irq_{enter,exit} are called so that we don't confuse things. This affects things like timekeeping, NO_HZ and RCU, basically everything with a hook in irq_enter/exit. Explicit examples of things going wrong are: sched_clock_cpu() -- has a callback when leaving NO_HZ state to take a new reading from GTOD and TSC. Without this callback, time is stuck in the past. RCU -- needs in_irq() to work in order to avoid some nasty deadlocks Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | * | | rcu: protect __rcu_read_unlock() against scheduler-using irq handlersPaul E. McKenney2011-07-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The addition of RCU read-side critical sections within runqueue and priority-inheritance lock critical sections introduced some deadlock cycles, for example, involving interrupts from __rcu_read_unlock() where the interrupt handlers call wake_up(). This situation can cause the instance of __rcu_read_unlock() invoked from interrupt to do some of the processing that would otherwise have been carried out by the task-level instance of __rcu_read_unlock(). When the interrupt-level instance of __rcu_read_unlock() is called with a scheduler lock held from interrupt-entry/exit situations where in_irq() returns false, deadlock can result. This commit resolves these deadlocks by using negative values of the per-task ->rcu_read_lock_nesting counter to indicate that an instance of __rcu_read_unlock() is in flight, which in turn prevents instances from interrupt handlers from doing any special processing. This patch is inspired by Steven Rostedt's earlier patch that similarly made __rcu_read_unlock() guard against interrupt-mediated recursion (see https://lkml.org/lkml/2011/7/15/326), but this commit refines Steven's approach to avoid the need for preemption disabling on the __rcu_read_unlock() fastpath and to also avoid the need for manipulating a separate per-CPU variable. This patch avoids need for preempt_disable() by instead using negative values of the per-task ->rcu_read_lock_nesting counter. Note that nested rcu_read_lock()/rcu_read_unlock() pairs are still permitted, but they will never see ->rcu_read_lock_nesting go to zero, and will therefore never invoke rcu_read_unlock_special(), thus preventing them from seeing the RCU_READ_UNLOCK_BLOCKED bit should it be set in ->rcu_read_unlock_special. This patch also adds a check for ->rcu_read_unlock_special being negative in rcu_check_callbacks(), thus preventing the RCU_READ_UNLOCK_NEED_QS bit from being set should a scheduling-clock interrupt occur while __rcu_read_unlock() is exiting from an outermost RCU read-side critical section. Of course, __rcu_read_unlock() can be preempted during the time that ->rcu_read_lock_nesting is negative. This could result in the setting of the RCU_READ_UNLOCK_BLOCKED bit after __rcu_read_unlock() checks it, and would also result it this task being queued on the corresponding rcu_node structure's blkd_tasks list. Therefore, some later RCU read-side critical section would enter rcu_read_unlock_special() to clean up -- which could result in deadlock if that critical section happened to be in the scheduler where the runqueue or priority-inheritance locks were held. This situation is dealt with by making rcu_preempt_note_context_switch() check for negative ->rcu_read_lock_nesting, thus refraining from queuing the task (and from setting RCU_READ_UNLOCK_BLOCKED) if we are already exiting from the outermost RCU read-side critical section (in other words, we really are no longer actually in that RCU read-side critical section). In addition, rcu_preempt_note_context_switch() invokes rcu_read_unlock_special() to carry out the cleanup in this case, which clears out the ->rcu_read_unlock_special bits and dequeues the task (if necessary), in turn avoiding needless delay of the current RCU grace period and needless RCU priority boosting. It is still illegal to call rcu_read_unlock() while holding a scheduler lock if the prior RCU read-side critical section has ever had either preemption or irqs enabled. However, the common use case is legal, namely where then entire RCU read-side critical section executes with irqs disabled, for example, when the scheduler lock is held across the entire lifetime of the RCU read-side critical section. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | * | | rcu: Streamline code produced by __rcu_read_unlock()Paul E. McKenney2011-07-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Given some common flag combinations, particularly -Os, gcc will inline rcu_read_unlock_special() despite its being in an unlikely() clause. Use noinline to prohibit this misoptimization. In addition, move the second barrier() in __rcu_read_unlock() so that it is not on the common-case code path. This will allow the compiler to generate better code for the common-case path through __rcu_read_unlock(). Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
| | * | | rcu: Fix RCU_BOOST race handling current->rcu_read_unlock_specialPaul E. McKenney2011-07-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The RCU_BOOST commits for TREE_PREEMPT_RCU introduced an other-task write to a new RCU_READ_UNLOCK_BOOSTED bit in the task_struct structure's ->rcu_read_unlock_special field, but, as noted by Steven Rostedt, without correctly synchronizing all accesses to ->rcu_read_unlock_special. This could result in bits in ->rcu_read_unlock_special being spuriously set and cleared due to conflicting accesses, which in turn could result in deadlocks between the rcu_node structure's ->lock and the scheduler's rq and pi locks. These deadlocks would result from RCU incorrectly believing that the just-ended RCU read-side critical section had been preempted and/or boosted. If that RCU read-side critical section was executed with either rq or pi locks held, RCU's ensuing (incorrect) calls to the scheduler would cause the scheduler to attempt to once again acquire the rq and pi locks, resulting in deadlock. More complex deadlock cycles are also possible, involving multiple rq and pi locks as well as locks from multiple rcu_node structures. This commit fixes synchronization by creating ->rcu_boosted field in task_struct that is accessed and modified only when holding the ->lock in the rcu_node structure on which the task is queued (on that rcu_node structure's ->blkd_tasks list). This results in tasks accessing only their own current->rcu_read_unlock_special fields, making unsynchronized access once again legal, and keeping the rcu_read_unlock() fastpath free of atomic instructions and memory barriers. The reason that the rcu_read_unlock() fastpath does not need to access the new current->rcu_boosted field is that this new field cannot be non-zero unless the RCU_READ_UNLOCK_BLOCKED bit is set in the current->rcu_read_unlock_special field. Therefore, rcu_read_unlock() need only test current->rcu_read_unlock_special: if that is zero, then current->rcu_boosted must also be zero. This bug does not affect TINY_PREEMPT_RCU because this implementation of RCU accesses current->rcu_read_unlock_special with irqs disabled, thus preventing races on the !SMP systems that TINY_PREEMPT_RCU runs on. Maybe-reported-by: Dave Jones <davej@redhat.com> Maybe-reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
| | * | | rcu: decrease rcu_report_exp_rnp coupling with schedulerPaul E. McKenney2011-07-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PREEMPT_RCU read-side critical sections blocking an expedited grace period invoke rcu_report_exp_rnp(). When the last such critical section has completed, rcu_report_exp_rnp() invokes the scheduler to wake up the task that invoked synchronize_rcu_expedited() -- needlessly holding the root rcu_node structure's lock while doing so, thus needlessly providing a way for RCU and the scheduler to deadlock. This commit therefore releases the root rcu_node structure's lock before calling wake_up(). Reported-by: Ed Tomlinson <edt@aei.ca> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* | | | | Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds2011-07-20
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: Avoid creating superfluous NUMA domains on non-NUMA systems sched: Allow for overlapping sched_domain spans sched: Break out cpu_power from the sched_group structure
| * | | | | sched: Avoid creating superfluous NUMA domains on non-NUMA systemsPeter Zijlstra2011-07-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When creating sched_domains, stop when we've covered the entire target span instead of continuing to create domains, only to later find they're redundant and throw them away again. This avoids single node systems from touching funny NUMA sched_domain creation code and reduces the risks of the new SD_OVERLAP code. Requested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Anton Blanchard <anton@samba.org> Cc: mahesh@linux.vnet.ibm.com Cc: benh@kernel.crashing.org Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1311180177.29152.57.camel@twins Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | | sched: Allow for overlapping sched_domain spansPeter Zijlstra2011-07-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow for sched_domain spans that overlap by giving such domains their own sched_group list instead of sharing the sched_groups amongst each-other. This is needed for machines with more than 16 nodes, because sched_domain_node_span() will generate a node mask from the 16 nearest nodes without regard if these masks have any overlap. Currently sched_domains have a sched_group that maps to their child sched_domain span, and since there is no overlap we share the sched_group between the sched_domains of the various CPUs. If however there is overlap, we would need to link the sched_group list in different ways for each cpu, and hence sharing isn't possible. In order to solve this, allocate private sched_groups for each CPU's sched_domain but have the sched_groups share a sched_group_power structure such that we can uniquely track the power. Reported-and-tested-by: Anton Blanchard <anton@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-08bxqw9wis3qti9u5inifh3y@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | | sched: Break out cpu_power from the sched_group structurePeter Zijlstra2011-07-20
| |/ / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to prepare for non-unique sched_groups per domain, we need to carry the cpu_power elsewhere, so put a level of indirection in. Reported-and-tested-by: Anton Blanchard <anton@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-qkho2byuhe4482fuknss40ad@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | | Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds2011-07-20
|\ \ \ \ \ | |/ / / / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86. reboot: Make Dell Latitude E6320 use reboot=pci x86, doc only: Correct real-mode kernel header offset for init_size x86: Disable AMD_NUMA for 32bit for now
| * | | | x86. reboot: Make Dell Latitude E6320 use reboot=pciMaxime Ripard2011-07-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Dell Latitude E6320 doesn't reboot unless reboot=pci is set. Force it thanks to DMI. Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Link: http://lkml.kernel.org/r/1309269451-4966-1-git-send-email-maxime.ripard@free-electrons.com Cc: Matthew Garrett <mjg@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
| * | | | x86, doc only: Correct real-mode kernel header offset for init_sizeDarren Hart2011-07-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The real-mode kernel header init_size field is located at 0x260 per the field listing in th e"REAL-MODE KERNEL HEADER" section. It is listed as 0x25c in the "DETAILS OF HEADER FIELDS" section, which overlaps with pref_address. Correct the details listing to 0x260. Signed-off-by: Darren Hart <dvhart@linux.intel.com> Link: http://lkml.kernel.org/r/541cf88e2dfe5b8186d8b96b136d892e769a68c1.1310441260.git.dvhart@linux.intel.com CC: H. Peter Anvin <hpa@zytor.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * | | | x86: Disable AMD_NUMA for 32bit for nowTejun Heo2011-07-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 2706a0bf7b ("x86, NUMA: Enable CONFIG_AMD_NUMA on 32bit too") enabled AMD NUMA for 32bit too. Unfortunately, SPARSEMEM on 32bit had rather coarse (512MiB) addr->node mapping granularity due to lack of space in page->flags. This led to boot failure on certain AMD NUMA machines which had 128MiB alignment on nodes. Patches to properly detect this condition and reject NUMA configuration are posted[1] but deemed too pervasive for merge at this point (-rc6). Disable AMD NUMA for 32bit for now and re-enable once the detection logic is merged. [1] http://thread.gmane.org/gmane.linux.kernel/1161279/focus=1162583 Reported-by: Hans Rosenfeld <hans.rosenfeld@amd.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Conny Seidel <conny.seidel@amd.com> Link: http://lkml.kernel.org/r/20110711083432.GC943@htj.dyndns.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | | Merge branch 'for-linus' of ↵Linus Torvalds2011-07-20
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: ceph: fix file mode calculation
| * | | | | ceph: fix file mode calculationSage Weil2011-07-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | open(2) must always include one of O_RDONLY, O_WRONLY, or O_RDWR. No need for any O_APPEND special case. Passing O_WRONLY|O_RDWR is undefined according to the man page, but the Linux VFS interprets this as O_RDWR, so we'll do the same. This fixes open(2) with flags O_RDWR|O_APPEND, which was incorrectly being translated to readonly. Reported-by: Fyodor Ustinov <ufm@ufm.su> Signed-off-by: Sage Weil <sage@newdream.net>
* | | | | | Merge branch 'fixes' of ↵Linus Torvalds2011-07-20
|\ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/arm/linux-arm-soc * 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/linux-arm-soc: davinci: DM365 EVM: fix video input mux bits ARM: davinci: Check for NULL return from irq_alloc_generic_chip arm: davinci: Fix low level gpio irq handlers' argument
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-20 14:47:41 -0500