Messages in this thread | | | Date | Tue, 30 Nov 2010 09:38:04 +0900 | From | Daisuke Nishimura <> | Subject | Re: [PATCH 53 of 66] add numa awareness to hugepage allocations |
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On Mon, 29 Nov 2010 17:11:03 +0100 Andrea Arcangeli <aarcange@redhat.com> wrote:
> On Mon, Nov 29, 2010 at 02:38:01PM +0900, Daisuke Nishimura wrote: > > I think this should be: > > > > if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { > > #ifdef CONFIG_NUMA > > put_page(new_page); > > #endif > > goto out; > > } > > Hmm no, the change you suggest would generate memory corruption with > use after free.
I'm sorry if I miss something, "new_page" will be reused in !CONFIG_NUMA case as you say, but, in CONFIG_NUMA case, it is allocated in this function (collapse_huge_page()) by alloc_hugepage_vma(), and is not freed when memcg's charge failed. Actually, we do in collapse_huge_page(): if (unlikely(!isolated)) { ... #ifdef CONFIG_NUMA put_page(new_page); #endif goto out; } later. I think we need a similar logic in memcg's failure path too.
Thanks, Daisuke Nishimura.
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