Messages in this thread | | | Date | Wed, 27 Mar 2013 14:52:50 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH 03/10] soft-offline: use migrate_pages() instead of migrate_huge_page() |
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On Tue 26-03-13 16:59:40, Aneesh Kumar K.V wrote: > Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> writes: [...] > > diff --git v3.9-rc3.orig/mm/memory-failure.c v3.9-rc3/mm/memory-failure.c > > index df0694c..4e01082 100644 > > --- v3.9-rc3.orig/mm/memory-failure.c > > +++ v3.9-rc3/mm/memory-failure.c > > @@ -1467,6 +1467,7 @@ static int soft_offline_huge_page(struct page *page, int flags) > > int ret; > > unsigned long pfn = page_to_pfn(page); > > struct page *hpage = compound_head(page); > > + LIST_HEAD(pagelist); > > > > /* > > * This double-check of PageHWPoison is to avoid the race with > > @@ -1482,12 +1483,20 @@ static int soft_offline_huge_page(struct page *page, int flags) > > unlock_page(hpage); > > > > /* Keep page count to indicate a given hugepage is isolated. */ > > - ret = migrate_huge_page(hpage, new_page, MPOL_MF_MOVE_ALL, > > - MIGRATE_SYNC); > > - put_page(hpage); > > + list_move(&hpage->lru, &pagelist); > > we use hpage->lru to add the hpage to h->hugepage_activelist. This will > break a hugetlb cgroup removal isn't it ?
This particular part will not break removal because hugetlb_cgroup_css_offline loops until hugetlb_cgroup_have_usage is 0.
Little bit offtopic: Btw. hugetlb migration breaks to charging even before this patchset AFAICS. The above put_page should remove the last reference and then it will uncharge it but I do not see anything that would charge a new page. This is all because regula LRU pages are uncharged when they are unmapped. But this a different story not related to this series.
[...] -- Michal Hocko SUSE Labs
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