On Thu, Feb 04, 2016 at 07:42:26PM +0300, Vladimir Davydov wrote: > On Thu, Feb 04, 2016 at 04:08:01PM +0900, Naoya Horiguchi wrote: > > Currently /proc/kpageflags returns nothing for "tail" buddy pages, which > > is inconvenient when grasping how free pages are distributed. This patch > > sets KPF_BUDDY for such pages. > > Looks reasonable to me, > > Reviewed-by: Vladimir Davydov <vdavy...@virtuozzo.com>
Thank you. > > > > With this patch: > > > > $ grep MemFree /proc/meminfo ; tools/vm/page-types -b buddy > > MemFree: 3134992 kB > > flags page-count MB symbolic-flags > > long-symbolic-flags > > 0x0000000000000400 779272 3044 > > __________B_______________________________ buddy > > 0x0000000000000c00 4385 17 > > __________BM______________________________ buddy,mmap > > total 783657 3061 > > Why are buddy pages reported as mmapped? That looks weird. Shouldn't we > fix it? Something like this, may be? > > -- > From: Vladimir Davydov <vdavy...@virtuozzo.com> > Subject: [PATCH] proc: kpageflags: do not report buddy and balloon pages as > mapped > > PageBuddy and PageBalloon are not usual page flags - they are identified > by a special negative (so as not to confuse with mapped pages) value of > page->_mapcount. Since /proc/kpageflags uses page_mapcount helper to > check if a page is mapped, it reports pages of these kinds as being > mapped, which is confusing. Fix that by replacing page_mapcount with > page_mapped. > > Signed-off-by: Vladimir Davydov <vdavy...@virtuozzo.com> > > diff --git a/fs/proc/page.c b/fs/proc/page.c > index b2855eea5405..332450d87ea4 100644 > --- a/fs/proc/page.c > +++ b/fs/proc/page.c > @@ -105,7 +105,7 @@ u64 stable_page_flags(struct page *page) > * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the > * simple test in page_mapcount() is not enough. We can do s/page_mapcount/page_mapped/ for this line too. > */ > - if (!PageSlab(page) && page_mapcount(page)) > + if (!PageSlab(page) && page_mapped(page)) Look good to me. Acked-by: Naoya Horiguchi <n-horigu...@ah.jp.nec.com> > u |= 1 << KPF_MMAP; > if (PageAnon(page)) > u |= 1 << KPF_ANON;
