- 14 4月, 2011 1 次提交
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由 Peter Zijlstra 提交于
Since we now have p->on_cpu unconditionally available, use it to re-implement mutex_spin_on_owner. Requested-by: NThomas Gleixner <tglx@linutronix.de> Reviewed-by: NFrank Rowand <frank.rowand@am.sony.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110405152728.826338173@chello.nl
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- 31 3月, 2011 1 次提交
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由 Lucas De Marchi 提交于
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>
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- 05 1月, 2011 1 次提交
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由 Gerald Schaefer 提交于
The spinning mutex implementation uses cpu_relax() in busy loops as a compiler barrier. Depending on the architecture, cpu_relax() may do more than needed in this specific mutex spin loops. On System z we also give up the time slice of the virtual cpu in cpu_relax(), which prevents effective spinning on the mutex. This patch replaces cpu_relax() in the spinning mutex code with arch_mutex_cpu_relax(), which can be defined by each architecture that selects HAVE_ARCH_MUTEX_CPU_RELAX. The default is still cpu_relax(), so this patch should not affect other architectures than System z for now. Signed-off-by: NGerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1290437256.7455.4.camel@thinkpad> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 26 11月, 2010 1 次提交
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由 Gerald Schaefer 提交于
The spinning mutex implementation uses cpu_relax() in busy loops as a compiler barrier. Depending on the architecture, cpu_relax() may do more than needed in this specific mutex spin loops. On System z we also give up the time slice of the virtual cpu in cpu_relax(), which prevents effective spinning on the mutex. This patch replaces cpu_relax() in the spinning mutex code with arch_mutex_cpu_relax(), which can be defined by each architecture that selects HAVE_ARCH_MUTEX_CPU_RELAX. The default is still cpu_relax(), so this patch should not affect other architectures than System z for now. Signed-off-by: NGerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1290437256.7455.4.camel@thinkpad> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 03 9月, 2010 1 次提交
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由 Randy Dunlap 提交于
Fix kernel-doc notation in linux/mutex.h and kernel/mutex.c, then add these 2 files to the kernel-locking docbook as the Mutex API reference chapter. Add one API function to mutex-design.txt and correct a typo in that file. Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com> Cc: Rusty Russell <rusty@rustcorp.com.au> LKML-Reference: <20100902154816.6cc2f9ad.randy.dunlap@oracle.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 19 5月, 2010 1 次提交
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由 Tony Breeds 提交于
Currently, we can hit a nasty case with optimistic spinning on mutexes: CPU A tries to take a mutex, while holding the BKL CPU B tried to take the BLK while holding the mutex This looks like a AB-BA scenario but in practice, is allowed and happens due to the auto-release on schedule() nature of the BKL. In that case, the optimistic spinning code can get us into a situation where instead of going to sleep, A will spin waiting for B who is spinning waiting for A, and the only way out of that loop is the need_resched() test in mutex_spin_on_owner(). This patch fixes it by completely disabling spinning if we own the BKL. This adds one more detail to the extensive list of reasons why it's a bad idea for kernel code to be holding the BKL. Signed-off-by: NTony Breeds <tony@bakeyournoodle.com> Acked-by: NLinus Torvalds <torvalds@linux-foundation.org> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: <stable@kernel.org> LKML-Reference: <20100519054636.GC12389@ozlabs.org> [ added an unlikely() attribute to the branch ] Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 03 12月, 2009 1 次提交
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由 Frederic Weisbecker 提交于
Introduce CONFIG_MUTEX_SPIN_ON_OWNER so that we can centralize in a single place the conditions that determine its definition and use. Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Acked-by: NPeter Zijlstra <peterz@infradead.org> LKML-Reference: <1259783357-8542-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org>
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- 30 4月, 2009 1 次提交
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由 Andrew Morton 提交于
include/linux/mutex.h:136: warning: 'mutex_lock' declared inline after being called include/linux/mutex.h:136: warning: previous declaration of 'mutex_lock' was here uninline it. [ Impact: clean up and uninline, address compiler warning ] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Eric Paris <eparis@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <200904292318.n3TNIsi6028340@imap1.linux-foundation.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 21 4月, 2009 1 次提交
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由 Peter Zijlstra 提交于
Lai Jiangshan's patch reminded me that I promised Nick to remove that extra call overhead in schedule(). Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20090313112300.927414207@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 10 4月, 2009 1 次提交
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由 Heiko Carstens 提交于
Impact: performance regression fix for s390 The adaptive spinning mutexes will not always do what one would expect on virtualized architectures like s390. Especially the cpu_relax() loop in mutex_spin_on_owner might hurt if the mutex holding cpu has been scheduled away by the hypervisor. We would end up in a cpu_relax() loop when there is no chance that the state of the mutex changes until the target cpu has been scheduled again by the hypervisor. For that reason we should change the default behaviour to no-spin on s390. We do have an instruction which allows to yield the current cpu in favour of a different target cpu. Also we have an instruction which allows us to figure out if the target cpu is physically backed. However we need to do some performance tests until we can come up with a solution that will do the right thing on s390. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> LKML-Reference: <20090409184834.7a0df7b2@osiris.boeblingen.de.ibm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 06 4月, 2009 1 次提交
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由 H. Peter Anvin 提交于
Impact: build fix mutex_lock() is was defined inline in kernel/mutex.c, but wasn't declared so not in <linux/mutex.h>. This didn't cause a problem until checkin 3a2d367d9aabac486ac4444c6c7ec7a1dab16267 added the atomic_dec_and_mutex_lock() inline in between declaration and definion. This broke building with CONFIG_ALLOW_WARNINGS=n, e.g. make allnoconfig. Either from the source code nor the allnoconfig binary output I cannot find any internal references to mutex_lock() in kernel/mutex.c, so presumably this "inline" is now-useless legacy. Cc: Eric Paris <eparis@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Orig-LKML-Reference: <tip-3a2d367d9aabac486ac4444c6c7ec7a1dab16267@git.kernel.org> Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
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- 15 1月, 2009 4 次提交
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由 Chris Mason 提交于
Spin more agressively. This is less fair but also markedly faster. The numbers: * dbench 50 (higher is better): spin 1282MB/s v10 548MB/s v10 no wait 1868MB/s * 4k creates (numbers in files/second higher is better): spin avg 200.60 median 193.20 std 19.71 high 305.93 low 186.82 v10 avg 180.94 median 175.28 std 13.91 high 229.31 low 168.73 v10 no wait avg 232.18 median 222.38 std 22.91 high 314.66 low 209.12 * File stats (numbers in seconds, lower is better): spin 2.27s v10 5.1s v10 no wait 1.6s ( The source changes are smaller than they look, I just moved the need_resched checks in __mutex_lock_common after the cmpxchg. ) Signed-off-by: NChris Mason <chris.mason@oracle.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Change mutex contention behaviour such that it will sometimes busy wait on acquisition - moving its behaviour closer to that of spinlocks. This concept got ported to mainline from the -rt tree, where it was originally implemented for rtmutexes by Steven Rostedt, based on work by Gregory Haskins. Testing with Ingo's test-mutex application (http://lkml.org/lkml/2006/1/8/50) gave a 345% boost for VFS scalability on my testbox: # ./test-mutex-shm V 16 10 | grep "^avg ops" avg ops/sec: 296604 # ./test-mutex-shm V 16 10 | grep "^avg ops" avg ops/sec: 85870 The key criteria for the busy wait is that the lock owner has to be running on a (different) cpu. The idea is that as long as the owner is running, there is a fair chance it'll release the lock soon, and thus we'll be better off spinning instead of blocking/scheduling. Since regular mutexes (as opposed to rtmutexes) do not atomically track the owner, we add the owner in a non-atomic fashion and deal with the races in the slowpath. Furthermore, to ease the testing of the performance impact of this new code, there is means to disable this behaviour runtime (without having to reboot the system), when scheduler debugging is enabled (CONFIG_SCHED_DEBUG=y), by issuing the following command: # echo NO_OWNER_SPIN > /debug/sched_features This command re-enables spinning again (this is also the default): # echo OWNER_SPIN > /debug/sched_features Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
The problem is that dropping the spinlock right before schedule is a voluntary preemption point and can cause a schedule, right after which we schedule again. Fix this inefficiency by keeping preemption disabled until we schedule, do this by explicity disabling preemption and providing a schedule() variant that assumes preemption is already disabled. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Remove a local variable by combining an assingment and test in one. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 24 11月, 2008 1 次提交
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由 Török Edwin 提交于
Impact: fix build failure on llvm-gcc-4.2 According to the gcc manual, the 'used' attribute should be applied to functions referenced only from inline assembly. This fixes a build failure with llvm-gcc-4.2, which deleted __mutex_lock_slowpath, __mutex_unlock_slowpath. Signed-off-by: NTörök Edwin <edwintorok@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 20 10月, 2008 1 次提交
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由 Peter Zijlstra 提交于
We currently only provide points that have to wait on contention, also lists the points we have to wait for. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 29 7月, 2008 1 次提交
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由 Randy Dunlap 提交于
Fix @key parameter to mutex_init() and one of its callers. Warning(linux-2.6.26-git11//drivers/base/class.c:210): No description found for parameter 'key' Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com> Acked-by: NGreg Kroah-Hartman <gregkh@suse.de> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 10 6月, 2008 1 次提交
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由 Oleg Nesterov 提交于
Change __mutex_lock_common() to use signal_pending_state() for the sake of the code re-use. This adds 7 bytes to kernel/mutex.o, but afaics only because gcc isn't smart enough. (btw, uninlining of __mutex_lock_common() shrinks .text from 2722 to 1542, perhaps it is worth doing). Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 09 2月, 2008 1 次提交
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由 Harvey Harrison 提交于
[akpm@linux-foundation.org: coding-style fixes] Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 12月, 2007 1 次提交
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由 Liam R. Howlett 提交于
Similar to mutex_lock_interruptible, it can be interrupted by a fatal signal only. Signed-off-by: NLiam R. Howlett <howlett@gmail.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
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- 12 10月, 2007 1 次提交
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由 Peter Zijlstra 提交于
The fancy mutex_lock fastpath has too many indirections to track the caller hence all contentions are perceived to come from mutex_lock(). Avoid this by explicitly not using the fastpath code (it was disabled already anyway). Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 20 7月, 2007 2 次提交
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由 Peter Zijlstra 提交于
__acquire | lock _____ | \ | __contended | | | wait | _______/ |/ | __acquired | __release | unlock We measure acquisition and contention bouncing. This is done by recording a cpu stamp in each lock instance. Contention bouncing requires the cpu stamp to be set on acquisition. Hence we move __acquired into the generic path. __acquired is then used to measure acquisition bouncing by comparing the current cpu with the old stamp before replacing it. __contended is used to measure contention bouncing (only useful for preemptable locks) [akpm@linux-foundation.org: cleanups] Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Peter Zijlstra 提交于
Call the new lockstat tracking functions from the various lock primitives. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: NIngo Molnar <mingo@elte.hu> Acked-by: NJason Baron <jbaron@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 10 5月, 2007 1 次提交
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由 Roman Zippel 提交于
Recently a few direct accesses to the thread_info in the task structure snuck back, so this wraps them with the appropriate wrapper. Signed-off-by: NRoman Zippel <zippel@linux-m68k.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 12月, 2006 1 次提交
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由 NeilBrown 提交于
md_open takes ->reconfig_mutex which causes lockdep to complain. This (normally) doesn't have deadlock potential as the possible conflict is with a reconfig_mutex in a different device. I say "normally" because if a loop were created in the array->member hierarchy a deadlock could happen. However that causes bigger problems than a deadlock and should be fixed independently. So we flag the lock in md_open as a nested lock. This requires defining mutex_lock_interruptible_nested. Cc: Ingo Molnar <mingo@elte.hu> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NNeil Brown <neilb@suse.de> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 04 7月, 2006 4 次提交
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由 Ingo Molnar 提交于
Use the lock validator framework to prove mutex locking correctness. Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NArjan van de Ven <arjan@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Ingo Molnar 提交于
Work around weird section nesting build bug causing smp-alternatives failures under certain circumstances. Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NArjan van de Ven <arjan@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Ingo Molnar 提交于
Generic lock debugging: - generalized lock debugging framework. For example, a bug in one lock subsystem turns off debugging in all lock subsystems. - got rid of the caller address passing (__IP__/__IP_DECL__/etc.) from the mutex/rtmutex debugging code: it caused way too much prototype hackery, and lockdep will give the same information anyway. - ability to do silent tests - check lock freeing in vfree too. - more finegrained debugging options, to allow distributions to turn off more expensive debugging features. There's no separate 'held mutexes' list anymore - but there's a 'held locks' stack within lockdep, which unifies deadlock detection across all lock classes. (this is independent of the lockdep validation stuff - lockdep first checks whether we are holding a lock already) Here are the current debugging options: CONFIG_DEBUG_MUTEXES=y CONFIG_DEBUG_LOCK_ALLOC=y which do: config DEBUG_MUTEXES bool "Mutex debugging, basic checks" config DEBUG_LOCK_ALLOC bool "Detect incorrect freeing of live mutexes" Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NArjan van de Ven <arjan@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Ingo Molnar 提交于
Rename DEBUG_WARN_ON() to the less generic DEBUG_LOCKS_WARN_ON() name, so that it's clear that this is a lock-debugging internal mechanism. Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 27 6月, 2006 1 次提交
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由 Ingo Molnar 提交于
It seems ppc64 wants to lock mutexes in early bootup code, with interrupts disabled, and they expect interrupts to stay disabled, else they crash. Work around this bug by making mutex debugging variants save/restore irq flags. Signed-off-by: NIngo Molnar <mingo@elte.hu> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 11 1月, 2006 3 次提交
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由 Ingo Molnar 提交于
Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Ingo Molnar 提交于
Mark mutex_lock() and mutex_lock_interruptible() as might_sleep() functions. Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Ingo Molnar 提交于
Call the mutex slowpath more conservatively - e.g. FRAME_POINTERS can change the calling convention, in which case a direct branch to the slowpath becomes illegal. Bug found by Hugh Dickins. Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 10 1月, 2006 1 次提交
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由 Ingo Molnar 提交于
mutex implementation, core files: just the basic subsystem, no users of it. Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NArjan van de Ven <arjan@infradead.org>
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