Messages in this thread Patch in this message | | | From | Borislav Petkov <> | Subject | [PATCH 03/10] x86/asm: Tweak the comment about wmb() use for IO | Date | Tue, 26 Jan 2016 22:12:03 +0100 |
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From: "Michael S. Tsirkin" <mst@redhat.com>
On x86, we *do* still use the non-nop rmb()/wmb() for IO barriers, but even that is generally questionable.
Leave them around for historical reasons, unless somebody can point to a case where they care about the performance. Tweak the comment so people don't think they are strictly required in all cases.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: virtualization <virtualization@lists.linux-foundation.org> Link: http://lkml.kernel.org/r/1452715911-12067-4-git-send-email-mst@redhat.com Signed-off-by: Borislav Petkov <bp@suse.de> --- arch/x86/include/asm/barrier.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h index d2aa66a3a4b5..4f95b2affd88 100644 --- a/arch/x86/include/asm/barrier.h +++ b/arch/x86/include/asm/barrier.h @@ -6,8 +6,8 @@ /* * Force strict CPU ordering. - * And yes, this is required on UP too when we're talking - * to devices. + * + * And yes, this might be required on UP too when we're talking to devices. */ #ifdef CONFIG_X86_32 -- 2.3.5
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