Messages in this thread | | | Subject | Re: [PATCH] mm/page_isolation: don't putback unisolated page | From | David Hildenbrand <> | Date | Mon, 6 Sep 2021 11:40:29 +0200 |
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On 04.09.21 11:18, Miaohe Lin wrote: > If __isolate_free_page() failed, due to zone watermark check, the page is > still on the free list. But this page will be put back to free list again > via __putback_isolated_page() now. This may trigger page->flags checks in > __free_one_page() if PageReported is set. Or we will corrupt the free list > because list_add() will be called for pages already on another list. > > Fixes: 3c605096d315 ("mm/page_alloc: restrict max order of merging on isolated pageblock") > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > --- > mm/page_isolation.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/mm/page_isolation.c b/mm/page_isolation.c > index 9bb562d5d194..7d70d772525c 100644 > --- a/mm/page_isolation.c > +++ b/mm/page_isolation.c > @@ -93,10 +93,8 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype) > buddy_pfn = __find_buddy_pfn(pfn, order); > buddy = page + (buddy_pfn - pfn); > > - if (!is_migrate_isolate_page(buddy)) { > - __isolate_free_page(page, order); > - isolated_page = true; > - } > + if (!is_migrate_isolate_page(buddy)) > + isolated_page = !!__isolate_free_page(page, order); > } > } > >
Shouldn't we much rather force to ignore watermarks here and make sure __isolate_free_page() never fails?
-- Thanks,
David / dhildenb
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