Messages in this thread Patch in this message | | | Date | Thu, 4 Mar 2010 16:31:29 GMT | From | tip-bot for Masami Hiramatsu <> | Subject | [tip:perf/pebs] x86: Issue at least one memory barrier in stop_machine_text_poke() |
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Commit-ID: e5a11016643d1ab7172193591506d33a844734cc Gitweb: http://git.kernel.org/tip/e5a11016643d1ab7172193591506d33a844734cc Author: Masami Hiramatsu <mhiramat@redhat.com> AuthorDate: Wed, 3 Mar 2010 22:38:50 -0500 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Thu, 4 Mar 2010 11:39:21 +0100
x86: Issue at least one memory barrier in stop_machine_text_poke()
Fix stop_machine_text_poke() to issue smp_mb() before exiting waiting loop, and use cpu_relax() for waiting.
Changes in v2: - Don't use ACCESS_ONCE().
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Jason Baron <jbaron@redhat.com> LKML-Reference: <20100304033850.3819.74590.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- arch/x86/kernel/alternative.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index c41f13c..e0b8770 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -595,8 +595,8 @@ static int __kprobes stop_machine_text_poke(void *data) wrote_text = 1; } else { while (!wrote_text) - smp_rmb(); - sync_core(); + cpu_relax(); + smp_mb(); /* Load wrote_text before following execution */ } flush_icache_range((unsigned long)tpp->addr,
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