Messages in this thread | | | Date | Tue, 28 Apr 2015 15:37:24 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] compaction: fix isolate_migratepages_block() for THP=n |
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On Wed, 29 Apr 2015 01:28:28 +0300 "Kirill A. Shutemov" <kirill@shutemov.name> wrote:
> On Tue, Apr 28, 2015 at 03:14:20PM -0700, Andrew Morton wrote: > > On Mon, 27 Apr 2015 14:26:46 +0300 "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> wrote: > > > > > PageTrans* helpers are always-false if THP is disabled compile-time. > > > It means the fucntion will fail to detect hugetlb pages in this case. > > > > > > Let's use PageCompound() instead. With small tweak to how we calculate > > > next low_pfn it will make function ready to see tail pages. > > > > <scratches head> > > > > So this patch has no runtime effects at present? It is preparation for > > something else? > > I wrote this to fix bug I originally attributed to refcounting patchset, > but Sasha triggered the same bug on -next without the patchset applied: > > http://lkml.kernel.org/g/553EB993.7030401@oracle.com
Well why the heck didn't the changelog tell us this?!?!?
> Now I think it's related to changing of PageLRU() behaviour on tail page > by my page flags patchset.
So this patch is a bugfix against one of
page-flags-trivial-cleanup-for-pagetrans-helpers.patch page-flags-introduce-page-flags-policies-wrt-compound-pages.patch page-flags-define-pg_locked-behavior-on-compound-pages.patch page-flags-define-behavior-of-fs-io-related-flags-on-compound-pages.patch page-flags-define-behavior-of-lru-related-flags-on-compound-pages.patch page-flags-define-behavior-slb-related-flags-on-compound-pages.patch page-flags-define-behavior-of-xen-related-flags-on-compound-pages.patch page-flags-define-pg_reserved-behavior-on-compound-pages.patch page-flags-define-pg_swapbacked-behavior-on-compound-pages.patch page-flags-define-pg_swapcache-behavior-on-compound-pages.patch page-flags-define-pg_mlocked-behavior-on-compound-pages.patch page-flags-define-pg_uncached-behavior-on-compound-pages.patch page-flags-define-pg_uptodate-behavior-on-compound-pages.patch page-flags-look-on-head-page-if-the-flag-is-encoded-in-page-mapping.patch mm-sanitize-page-mapping-for-tail-pages.patch include-linux-page-flagsh-rename-macros-to-avoid-collisions.patch
Which one was the faulty patch?
> PageLRU() on tail pages now reports true if > head page is on LRU. It means no we can go futher insede > isolate_migratepages_block() with tail page.
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