Messages in this thread Patch in this message | | | Date | Thu, 5 Nov 2015 11:26:22 +0200 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH 3/4] thp: fix split vs. unmap race |
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On Wed, Nov 04, 2015 at 05:20:15PM +0800, Hillf Danton wrote: > > @@ -1135,20 +1135,12 @@ void do_page_add_anon_rmap(struct page *page, > > bool compound = flags & RMAP_COMPOUND; > > bool first; > > > > - if (PageTransCompound(page)) { > > + if (compound) { > > + atomic_t *mapcount; > > VM_BUG_ON_PAGE(!PageLocked(page), page); > > - if (compound) { > > - atomic_t *mapcount; > > - > > - VM_BUG_ON_PAGE(!PageTransHuge(page), page); > > - mapcount = compound_mapcount_ptr(page); > > - first = atomic_inc_and_test(mapcount); > > - } else { > > - /* Anon THP always mapped first with PMD */ > > - first = 0; > > - VM_BUG_ON_PAGE(!page_mapcount(page), page); > > - atomic_inc(&page->_mapcount); > > - } > > + VM_BUG_ON_PAGE(!PageTransHuge(page), page); > > + mapcount = compound_mapcount_ptr(page); > > + first = atomic_inc_and_test(mapcount); > > } else { > > VM_BUG_ON_PAGE(compound, page); > > Then this debug info is no longer needed. > > first = atomic_inc_and_test(&page->_mapcount);
Right.
diff --git a/mm/rmap.c b/mm/rmap.c index 0837487d3737..a9550b1f74cd 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1186,7 +1186,6 @@ void do_page_add_anon_rmap(struct page *page, mapcount = compound_mapcount_ptr(page); first = atomic_inc_and_test(mapcount); } else { - VM_BUG_ON_PAGE(compound, page); first = atomic_inc_and_test(&page->_mapcount); } -- Kirill A. Shutemov
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