Messages in this thread | | | Date | Thu, 18 Jul 2013 13:51:57 -0700 | From | Andrew Morton <> | Subject | Re: [RESEND][PATCH] mm: vmstats: tlb flush counters |
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On Wed, 17 Jul 2013 09:21:00 +0200 Ingo Molnar <mingo@kernel.org> wrote:
> > * Dave Hansen <dave@sr71.net> wrote: > > > I was investigating some TLB flush scaling issues and realized > > that we do not have any good methods for figuring out how many > > TLB flushes we are doing. > > > > It would be nice to be able to do these in generic code, but the > > arch-independent calls don't explicitly specify whether we > > actually need to do remote flushes or not. In the end, we really > > need to know if we actually _did_ global vs. local invalidations, > > so that leaves us with few options other than to muck with the > > counters from arch-specific code.
Spose so, if you really think it's worth it. It's all downside for uniprocessor machines. And for architectures which don't implement the counters, of course.
> > --- linux.git/include/linux/vm_event_item.h~tlb-vmstats 2013-07-16 16:41:56.478280438 -0700 > > +++ linux.git-davehans/include/linux/vm_event_item.h 2013-07-16 16:41:56.483280658 -0700 > > @@ -70,6 +70,11 @@ enum vm_event_item { PGPGIN, PGPGOUT, PS > > THP_ZERO_PAGE_ALLOC, > > THP_ZERO_PAGE_ALLOC_FAILED, > > #endif > > > > + NR_TLB_REMOTE_FLUSH, /* cpu tried to flush others' tlbs */ > > + NR_TLB_REMOTE_FLUSH_RECEIVED,/* cpu received ipi for flush */ > > + NR_TLB_LOCAL_FLUSH_ALL, > > + NR_TLB_LOCAL_FLUSH_ONE, > > + NR_TLB_LOCAL_FLUSH_ONE_KERNEL, > > Please fix the vertical alignment of comments.
I looked - this isn't practical.
It would be nice to actually document these things though. We don't *have* to squeeze the comment into the RHS.
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