Commit-ID: ca59809ff6d572ae58fc6bedf7500f5a60fdbd64 Gitweb: http://git.kernel.org/tip/ca59809ff6d572ae58fc6bedf7500f5a60fdbd64 Author: Michael S. Tsirkin <mst@xxxxxxxxxx> AuthorDate: Thu, 28 Jan 2016 19:02:51 +0200 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Fri, 29 Jan 2016 09:40:10 +0100 locking/x86: Use mb() around clflush() The following commit: f8e617f4582995f ("sched/idle/x86: Optimize unnecessary mwait_idle() resched IPIs") adds memory barriers around clflush(), but this seems wrong for UP since barrier() has no effect on clflush(). We really want MFENCE, so switch to mb() instead. Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx> Cc: Davidlohr Bueso <dbueso@xxxxxxx> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Len Brown <len.brown@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Mike Galbraith <bitbucket@xxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: virtualization <virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/1453921746-16178-5-git-send-email-mst@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/kernel/process.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 9f7c21c..9decee2 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -418,9 +418,9 @@ static void mwait_idle(void) if (!current_set_polling_and_test()) { trace_cpu_idle_rcuidle(1, smp_processor_id()); if (this_cpu_has(X86_BUG_CLFLUSH_MONITOR)) { - smp_mb(); /* quirk */ + mb(); /* quirk */ clflush((void *)¤t_thread_info()->flags); - smp_mb(); /* quirk */ + mb(); /* quirk */ } __monitor((void *)¤t_thread_info()->flags, 0, 0); _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
