* Ingo Molnar wrote: > > * Peter Zijlstra wrote: > > > On Tue, Jun 03, 2014 at 02:50:51PM -0700, Davidlohr Bueso wrote: > > > On Tue, 2014-06-03 at 13:48 +0200, Ingo Molnar wrote: > > > > Linus, > > > > > > > > Please pull the latest locking-core-for-linus git tree from: > > > > > > > > git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking-core-for-linus > > > > > > > > # HEAD: 3cf2f34e1a3d4d5ff209d087925cf950e52f4805 rwsem: Add comments to explain the meaning of the rwsem's count field > > > > > > > > The main changes in this cycle were: > > > > > > > > - reduced/streamlined smp_mb__*() interface that allows more usecases > > > > and makes the existing ones less buggy, especially in rarer > > > > architectures > > > > > > > > - add rwsem implementation comments > > > > > > > > - bump up lockdep limits > > > > > > So I guess the rwsem optimistic spinning stuff will be routed through > > > akpm then (which is already in -next for a while, through -mm). > > > > > > Also curious about why Peter's rewrite of the qrwlock_t was > > > removed from -tip... I noticed it was there for a few days then > > > disappeared. What am I missing? > > I merged it, but then it broke and I reported the breakage - and > zapped the bits to not create dependencies on broken bits. Unfortunately even with the latest bits from you the breakage I reported weeks ago is not resolved: In file included from include/linux/spinlock_types.h:15:0, from kernel/bounds.c:14: include/linux/spinlock_types_up.h:19:3: error: conflicting types for ‘arch_spinlock_t’ In file included from /home/mingo/linux/linux2/arch/x86/include/asm/paravirt_types.h:329:0, from /home/mingo/linux/linux2/arch/x86/include/asm/ptrace.h:64, from /home/mingo/linux/linux2/arch/x86/include/asm/alternative.h:8, from /home/mingo/linux/linux2/arch/x86/include/asm/bitops.h:16, from include/linux/bitops.h:33, from include/linux/kernel.h:10, from include/asm-generic/bug.h:13, from /home/mingo/linux/linux2/arch/x86/include/asm/bug.h:35, from include/linux/bug.h:4, from include/linux/page-flags.h:9, from kernel/bounds.c:9: /home/mingo/linux/linux2/arch/x86/include/asm/spinlock_types.h:33:3: note: previous declaration of ‘arch_spinlock_t’ was here In file included from include/linux/spinlock_types.h:15:0, from kernel/bounds.c:14: include/linux/spinlock_types_up.h:21:0: warning: "__ARCH_SPIN_LOCK_UNLOCKED" redefined [enabled by default] In file included from /home/mingo/linux/linux2/arch/x86/include/asm/paravirt_types.h:329:0, from /home/mingo/linux/linux2/arch/x86/include/asm/ptrace.h:64, from /home/mingo/linux/linux2/arch/x86/include/asm/alternative.h:8, from /home/mingo/linux/linux2/arch/x86/include/asm/bitops.h:16, from include/linux/bitops.h:33, from include/linux/kernel.h:10, from include/asm-generic/bug.h:13, from /home/mingo/linux/linux2/arch/x86/include/asm/bug.h:35, from include/linux/bug.h:4, from include/linux/page-flags.h:9, from kernel/bounds.c:9: /home/mingo/linux/linux2/arch/x86/include/asm/spinlock_types.h:35:0: note: this is the location of the previous definition In file included from include/linux/spinlock_types.h:15:0, from kernel/bounds.c:14: include/linux/spinlock_types_up.h:33:3: error: conflicting types for ‘arch_rwlock_t’ In file included from /home/mingo/linux/linux2/arch/x86/include/asm/spinlock_types.h:40:0, from /home/mingo/linux/linux2/arch/x86/include/asm/paravirt_types.h:329, from /home/mingo/linux/linux2/arch/x86/include/asm/ptrace.h:64, from /home/mingo/linux/linux2/arch/x86/include/asm/alternative.h:8, from /home/mingo/linux/linux2/arch/x86/include/asm/bitops.h:16, from include/linux/bitops.h:33, from include/linux/kernel.h:10, from include/asm-generic/bug.h:13, from /home/mingo/linux/linux2/arch/x86/include/asm/bug.h:35, from include/linux/bug.h:4, from include/linux/page-flags.h:9, from kernel/bounds.c:9: /home/mingo/linux/linux2/arch/x86/include/asm/rwlock.h:12:3: note: previous declaration of ‘arch_rwlock_t’ was here In file included from include/linux/spinlock_types.h:15:0, from kernel/bounds.c:14: include/linux/spinlock_types_up.h:35:0: warning: "__ARCH_RW_LOCK_UNLOCKED" redefined [enabled by default] In file included from /home/mingo/linux/linux2/arch/x86/include/asm/spinlock_types.h:40:0, from /home/mingo/linux/linux2/arch/x86/include/asm/paravirt_types.h:329, from /home/mingo/linux/linux2/arch/x86/include/asm/ptrace.h:64, from /home/mingo/linux/linux2/arch/x86/include/asm/alternative.h:8, from /home/mingo/linux/linux2/arch/x86/include/asm/bitops.h:16, from include/linux/bitops.h:33, from include/linux/kernel.h:10, from include/asm-generic/bug.h:13, from /home/mingo/linux/linux2/arch/x86/include/asm/bug.h:35, from include/linux/bug.h:4, from include/linux/page-flags.h:9, from kernel/bounds.c:9: /home/mingo/linux/linux2/arch/x86/include/asm/rwlock.h:45:0: note: this is the location of the previous definition config attached - I think the key aspect is !CONFIG_SMP. Not unexpected the breakage comes from: 5627b9d439cc4dfaab738b8c21eef10fb40733f8 is the first bad commit commit 5627b9d439cc4dfaab738b8c21eef10fb40733f8 Author: Waiman Long Date: Mon Feb 3 13:18:57 2014 +0100 x86, locking: Switch x86 to qrwlock-style rwlocks and optimize it Make x86 use the fair rwlock_t. Please also split the feature-enabling and the optimization into two separate patches. Thanks, Ingo