Will Deacon 0bce9c46bf mutex: Place lock in contended state after fastpath_lock failure ... ARM recently moved to asm-generic/mutex-xchg.h for its mutex implementation after the previous implementation was found to be missing some crucial memory barriers. However, this has revealed some problems running hackbench on SMP platforms due to the way in which the MUTEX_SPIN_ON_OWNER code operates. The symptoms are that a bunch of hackbench tasks are left waiting on an unlocked mutex and therefore never get woken up to claim it. This boils down to the following sequence of events: Task A Task B Task C Lock value 0 1 1 lock() 0 2 lock() 0 3 spin(A) 0 4 unlock() 1 5 lock() 0 6 cmpxchg(1,0) 0 7 contended() -1 8 lock() 0 9 spin(C) 0 10 unlock() 1 11 cmpxchg(1,0) 0 12 unlock() 1 At this point, the lock is unlocked, but Task B is in an uninterruptible sleep with nobody to wake it up. This patch fixes the problem by ensuring we put the lock into the contended state if we fail to acquire it on the fastpath, ensuring that any blocked waiters are woken up when the mutex is released. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Chris Mason <chris.mason@fusionio.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: <stable@vger.kernel.org> Reviewed-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-6e9lrw2avczr0617fzl5vqb8@git.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>		2012-08-13 18:46:54 +02:00
..
bitops	Add #includes needed to permit the removal of asm/system.h	2012-03-28 18:30:03 +01:00
4level-fixup.h
atomic-long.h
atomic.h	Remove all #inclusions of asm/system.h	2012-03-28 18:30:03 +01:00
atomic64.h
audit_change_attr.h	audit: support the "standard" <asm-generic/unistd.h>	2011-05-04 14:41:28 -04:00
audit_dir_write.h	audit: support the "standard" <asm-generic/unistd.h>	2011-05-04 14:41:28 -04:00
audit_read.h	audit: support the "standard" <asm-generic/unistd.h>	2011-05-04 14:41:28 -04:00
audit_signal.h
audit_write.h	audit: support the "standard" <asm-generic/unistd.h>	2011-05-04 14:41:28 -04:00
auxvec.h
barrier.h	Create asm-generic/barrier.h	2012-03-28 18:30:03 +01:00
bitops.h	bitops: remove minix bitops from asm/bitops.h	2011-03-23 19:46:22 -07:00
bitsperlong.h	vsprintf: further optimize decimal conversion	2012-05-31 17:49:27 -07:00
bug.h	bug.h: Fix up CONFIG_BUG=n implicit function declarations.	2012-06-25 10:32:49 -07:00
bugs.h
cache.h
cacheflush.h	asm-generic/cacheflush.h: flush icache when copying to user pages	2011-05-25 08:39:37 -07:00
checksum.h	Add extra arch overrides to asm-generic/checksum.h	2011-11-01 07:34:21 -07:00
cmpxchg-local.h
cmpxchg.h	asm-generic: add linux/types.h to cmpxchg.h	2012-04-02 14:41:27 -07:00
cputime.h	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2012-01-06 08:44:54 -08:00
current.h
delay.h	asm-generic: delay.h fix udelay and ndelay for 8 bit args	2011-07-22 18:45:33 +02:00
device.h
div64.h
dma-coherent.h	common: dma-mapping: add support for generic dma_mmap_* calls	2012-07-30 12:25:46 +02:00
dma-contiguous.h	mm: cma: fix condition check when setting global cma area	2012-07-06 12:02:04 +02:00
dma-mapping-broken.h
dma-mapping-common.h	common: dma-mapping: introduce dma_get_sgtable() function	2012-07-30 12:25:46 +02:00
dma.h
emergency-restart.h
errno-base.h
errno.h	mm: make __get_user_pages return -EHWPOISON for HWPOISON page optionally	2011-03-17 13:08:27 -03:00
exec.h	Split arch_align_stack() out from asm-generic/system.h	2012-03-28 18:30:03 +01:00
fb.h
fcntl.h	c/r: fcntl: add F_GETOWNER_UIDS option	2012-07-30 17:25:21 -07:00
ftrace.h	asm-generic headers: add ftrace.h	2011-03-17 09:19:04 +08:00
futex.h	futex: Sanitize futex ops argument types	2011-03-11 12:23:31 +01:00
getorder.h	bitops: Add missing parentheses to new get_order macro	2012-02-24 10:39:27 -08:00
gpio.h	gpiolib: Remove 'const' from data argument of gpiochip_find()	2012-05-18 23:01:05 -06:00
hardirq.h
hw_irq.h
ide_iops.h
int-l64.h
int-ll64.h
io-64-nonatomic-hi-lo.h	asm-generic: architecture independent readq/writeq for 32bit environment	2012-02-21 16:47:28 -08:00
io-64-nonatomic-lo-hi.h	asm-generic: architecture independent readq/writeq for 32bit environment	2012-02-21 16:47:28 -08:00
io.h	lib: use generic pci_iomap on all architectures	2012-01-10 18:04:27 -08:00
ioctl.h
ioctls.h
iomap.h	[PARISC] fix compile break caused by iomap: make IOPORT/PCI mapping functions conditional	2012-02-27 09:43:30 -06:00
ipcbuf.h
irq.h
irq_regs.h
irqflags.h
Kbuild	KVM: Export asm-generic/kvm_para.h	2012-05-29 12:31:01 +03:00
Kbuild.asm
kdebug.h
kmap_types.h	asm-generic: remove km_type definitions	2012-07-24 15:27:30 +08:00
kvm_para.h	KVM: make asm-generic/kvm_para.h have an ifdef __KERNEL__ block	2012-05-21 17:47:52 +03:00
libata-portmap.h
linkage.h
local.h	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
local64.h	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
memory_model.h	mm: fix __page_to_pfn for a const struct page argument	2011-08-17 13:00:20 -07:00
mm_hooks.h
mman-common.h	coredump: add VM_NODUMP, MADV_NODUMP, MADV_CLEAR_NODUMP	2012-03-23 16:58:42 -07:00
mman.h
mmu.h
mmu_context.h
module.h
msgbuf.h
mutex-dec.h
mutex-null.h
mutex-xchg.h	mutex: Place lock in contended state after fastpath_lock failure	2012-08-13 18:46:54 +02:00
mutex.h
page.h	The following changes since commit 3ee72ca992	2012-01-10 17:39:40 -08:00
param.h	UAPI: Rearrange definition of HZ in asm-generic/param.h	2011-12-13 09:26:45 +00:00
parport.h
pci-bridge.h	PCI: work around Stratus ftServer broken PCIe hierarchy	2012-04-30 15:21:02 -06:00
pci-dma-compat.h
pci.h	PCI: collapse pcibios_resource_to_bus	2012-02-23 20:19:04 -07:00
pci_iomap.h	[PARISC] fix compile break caused by iomap: make IOPORT/PCI mapping functions conditional	2012-02-27 09:43:30 -06:00
percpu.h
pgalloc.h
pgtable-nopmd.h
pgtable-nopud.h
pgtable.h	thp: avoid atomic64_read in pmd_read_atomic for 32bit PAE	2012-06-20 14:39:35 -07:00
poll.h	epoll: introduce POLLFREE to flush ->signalfd_wqh before kfree()	2012-02-24 11:42:50 -08:00
posix_types.h	bury __kernel_nlink_t, make internal nlink_t consistent	2012-05-30 21:04:50 -04:00
ptrace.h	asm-generic/ptrace.h: start a common low level ptrace helper	2011-05-26 17:12:36 -07:00
resource.h	ulimit: raise default hard ulimit on number of files to 4096	2011-05-25 08:39:43 -07:00
rtc.h
rwsem.h	Hexagon: Add locking types and functions	2011-11-01 07:34:20 -07:00
scatterlist.h
sections.h	x86: Separate out entry text section	2011-03-08 17:22:11 +01:00
segment.h
sembuf.h
serial.h
setup.h
shmbuf.h
shmparam.h
siginfo.h	Linux 3.4-rc5	2012-05-04 12:46:40 +10:00
signal-defs.h
signal.h
sizes.h	ARM: 7430/1: sizes.h: move from asm-generic to <linux/sizes.h>	2012-06-28 17:14:34 +01:00
socket.h	net: Add framework to allow sending packets with customized CRC.	2012-02-24 01:37:35 -08:00
sockios.h
spinlock.h
stat.h
statfs.h	asm-generic: Use __BITS_PER_LONG in statfs.h	2012-04-30 12:55:15 -07:00
string.h
swab.h
switch_to.h	Split the switch_to() wrapper out of asm-generic/system.h	2012-03-28 18:30:03 +01:00
syscall.h	asm/syscall.h: add syscall_get_arch	2012-04-14 11:13:19 +10:00
syscalls.h
termbits.h
termios-base.h
termios.h
timex.h
tlb.h	mm/mmu_gather: enable tlb flush range in generic mmu_gather	2012-06-27 19:29:11 -07:00
tlbflush.h	BUG: headers with BUG/BUG_ON etc. need linux/bug.h	2012-03-04 17:54:34 -05:00
topology.h
types.h	consolidate umode_t declarations	2012-01-03 22:55:17 -05:00
uaccess-unaligned.h
uaccess.h	fix default __strnlen_user macro	2011-10-06 19:47:12 -04:00
ucontext.h
unaligned.h
unistd.h	compat: use sys_sendfile64() implementation for sendfile syscall	2012-03-27 13:36:57 -04:00
user.h
vga.h
vmlinux.lds.h	ftrace: Sort all function addresses, not just per page	2012-05-16 19:58:44 -04:00
word-at-a-time.h	word-at-a-time: make the interfaces truly generic	2012-05-26 11:33:40 -07:00
xor.h	sanitize <linux/prefetch.h> usage	2011-05-20 12:50:29 -07:00