search for: x86_oostor

The comment about wmb being non-nop is a left over from before commit 09df7c4c8097 ("x86: Remove CONFIG_X86_OOSTORE"). It makes no sense now: if you have an SMP system with out of order stores, making wmb not a nop will not help. Additionally, wmb is not a nop even for regular intel CPUs because of weird use-cases e.g. dealing with WC memory. Drop this comment. Signed-off-by: Michael S. Tsirkin <mst...

The comment about wmb being non-nop to deal with non-intel CPUs is a left over from before commit 09df7c4c8097 ("x86: Remove CONFIG_X86_OOSTORE"). It makes no sense now: in particular, wmb is not a nop even for regular intel CPUs because of weird use-cases e.g. dealing with WC memory. Drop this comment. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- arch/x86/include/asm/barrier.h | 4 ---- 1 file changed, 4 delet...

...e code changes (that people might want to test for performance) from comment changes approved by Linus, from (so far unreviewed) comment change I came up with myself. Lightly tested on my system. Michael S. Tsirkin (3): x86: drop mfence in favor of lock+addl x86: drop a comment left over from X86_OOSTORE x86: tweak the comment about use of wmb for IO arch/x86/include/asm/barrier.h | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) -- MST

...e code changes (that people might want to test for performance) from comment changes approved by Linus, from (so far unreviewed) comment change I came up with myself. Lightly tested on my system. Michael S. Tsirkin (3): x86: drop mfence in favor of lock+addl x86: drop a comment left over from X86_OOSTORE x86: tweak the comment about use of wmb for IO arch/x86/include/asm/barrier.h | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) -- MST

...from (so far unreviewed) changes I came up with myself. Changes from v2: add patch adding cc clobber for addl tweak commit log for patch 2 use addl at SP-4 (as opposed to SP) to reduce data dependencies Michael S. Tsirkin (4): x86: add cc clobber for addl x86: drop a comment left over from X86_OOSTORE x86: tweak the comment about use of wmb for IO x86: drop mfence in favor of lock+addl arch/x86/include/asm/barrier.h | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) -- MST

...from (so far unreviewed) changes I came up with myself. Changes from v2: add patch adding cc clobber for addl tweak commit log for patch 2 use addl at SP-4 (as opposed to SP) to reduce data dependencies Michael S. Tsirkin (4): x86: add cc clobber for addl x86: drop a comment left over from X86_OOSTORE x86: tweak the comment about use of wmb for IO x86: drop mfence in favor of lock+addl arch/x86/include/asm/barrier.h | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) -- MST

...o test for performance) from comment > changes approved by Linus, from (so far unreviewed) comment change I came up > with myself. > > Lightly tested on my system. > > Michael S. Tsirkin (3): > x86: drop mfence in favor of lock+addl > x86: drop a comment left over from X86_OOSTORE > x86: tweak the comment about use of wmb for IO > I would like to get feedback from the hardware team about the implications of this change, first. -hpa

...th myself. > > Changes from v2: > add patch adding cc clobber for addl > tweak commit log for patch 2 > use addl at SP-4 (as opposed to SP) to reduce data dependencies > > Michael S. Tsirkin (4): > x86: add cc clobber for addl > x86: drop a comment left over from X86_OOSTORE > x86: tweak the comment about use of wmb for IO First three look ok to me regardless of what happens with 4. So applied. Thanks. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.

On Thu, Jan 14, 2016 at 12:39:34PM +0100, Borislav Petkov wrote: > > Michael S. Tsirkin (4): > > x86: add cc clobber for addl > > x86: drop a comment left over from X86_OOSTORE > > x86: tweak the comment about use of wmb for IO > > First three look ok to me regardless of what happens with 4. So applied. Sorry - in which tree are these applied? Thanks, -- MST

...nge I came up > > > > with myself. > > > > > > > > Lightly tested on my system. > > > > > > > > Michael S. Tsirkin (3): > > > > x86: drop mfence in favor of lock+addl > > > > x86: drop a comment left over from X86_OOSTORE > > > > x86: tweak the comment about use of wmb for IO > > > > > > > > > > I would like to get feedback from the hardware team about the > > > implications of this change, first. > > > Any luck getting some feedback on this one? >...

On Thu, Jan 14, 2016 at 12:39:34PM +0100, Borislav Petkov wrote: > > Michael S. Tsirkin (4): > > x86: add cc clobber for addl > > x86: drop a comment left over from X86_OOSTORE > > x86: tweak the comment about use of wmb for IO > > First three look ok to me regardless of what happens with 4. So applied. Sorry - in which tree are these applied? Thanks, -- MST

...; > changes approved by Linus, from (so far unreviewed) comment change I came up > > with myself. > > > > Lightly tested on my system. > > > > Michael S. Tsirkin (3): > > x86: drop mfence in favor of lock+addl > > x86: drop a comment left over from X86_OOSTORE > > x86: tweak the comment about use of wmb for IO > > > > I would like to get feedback from the hardware team about the > implications of this change, first. > > -hpa > Hi hpa, Any luck getting some feedback on this one? Thanks, -- MST

...; > changes approved by Linus, from (so far unreviewed) comment change I came up > > with myself. > > > > Lightly tested on my system. > > > > Michael S. Tsirkin (3): > > x86: drop mfence in favor of lock+addl > > x86: drop a comment left over from X86_OOSTORE > > x86: tweak the comment about use of wmb for IO > > > > I would like to get feedback from the hardware team about the > implications of this change, first. > > -hpa > Hi hpa, Any luck getting some feedback on this one? Thanks, -- MST

...lflush, which requires mfence. Optimize smp_mb instead. Changes from v2: add patch adding cc clobber for addl tweak commit log for patch 2 use addl at SP-4 (as opposed to SP) to reduce data dependencies Michael S. Tsirkin (5): x86: add cc clobber for addl x86: drop a comment left over from X86_OOSTORE x86: tweak the comment about use of wmb for IO x86: use mb() around clflush x86: drop mfence in favor of lock+addl arch/x86/include/asm/barrier.h | 21 ++++++++++++--------- arch/x86/kernel/process.c | 4 ++-- 2 files changed, 14 insertions(+), 11 deletions(-) -- MST

...lflush, which requires mfence. Optimize smp_mb instead. Changes from v2: add patch adding cc clobber for addl tweak commit log for patch 2 use addl at SP-4 (as opposed to SP) to reduce data dependencies Michael S. Tsirkin (5): x86: add cc clobber for addl x86: drop a comment left over from X86_OOSTORE x86: tweak the comment about use of wmb for IO x86: use mb() around clflush x86: drop mfence in favor of lock+addl arch/x86/include/asm/barrier.h | 21 ++++++++++++--------- arch/x86/kernel/process.c | 4 ++-- 2 files changed, 14 insertions(+), 11 deletions(-) -- MST

...lflush, which requires mfence. Optimize smp_mb instead. Changes from v2: add patch adding cc clobber for addl tweak commit log for patch 2 use addl at SP-4 (as opposed to SP) to reduce data dependencies Michael S. Tsirkin (5): x86: add cc clobber for addl x86: drop a comment left over from X86_OOSTORE x86: tweak the comment about use of wmb for IO x86: use mb() around clflush x86: drop mfence in favor of lock+addl arch/x86/include/asm/barrier.h | 17 ++++++++--------- arch/x86/kernel/process.c | 4 ++-- 2 files changed, 10 insertions(+), 11 deletions(-) -- MST

...lflush, which requires mfence. Optimize smp_mb instead. Changes from v2: add patch adding cc clobber for addl tweak commit log for patch 2 use addl at SP-4 (as opposed to SP) to reduce data dependencies Michael S. Tsirkin (5): x86: add cc clobber for addl x86: drop a comment left over from X86_OOSTORE x86: tweak the comment about use of wmb for IO x86: use mb() around clflush x86: drop mfence in favor of lock+addl arch/x86/include/asm/barrier.h | 17 ++++++++--------- arch/x86/kernel/process.c | 4 ++-- 2 files changed, 10 insertions(+), 11 deletions(-) -- MST