Messages in this thread | | | Subject | Re: [v3 PATCH 2/4] mm: move mem_cgroup_uncharge out of __page_cache_release() | From | Yang Shi <> | Date | Mon, 24 Jun 2019 09:54:05 -0700 |
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On 6/13/19 10:13 AM, Yang Shi wrote: > > > On 6/13/19 4:39 AM, Kirill A. Shutemov wrote: >> On Thu, Jun 13, 2019 at 05:56:47AM +0800, Yang Shi wrote: >>> The later patch would make THP deferred split shrinker memcg aware, but >>> it needs page->mem_cgroup information in THP destructor, which is >>> called >>> after mem_cgroup_uncharge() now. >>> >>> So, move mem_cgroup_uncharge() from __page_cache_release() to compound >>> page destructor, which is called by both THP and other compound pages >>> except HugeTLB. And call it in __put_single_page() for single order >>> page. >> >> If I read the patch correctly, it will change behaviour for pages with >> NULL_COMPOUND_DTOR. Have you considered it? Are you sure it will not >> break >> anything? >
Hi Kirill,
Did this solve your concern? Any more comments on this series?
Thanks, Yang
> So far a quick search shows NULL_COMPOUND_DTOR is not used by any type > of compound page. The HugeTLB code sets destructor to > NULL_COMPOUND_DTOR when freeing hugetlb pages via hugetlb specific > destructor. > > The prep_new_page() would call prep_compound_page() if __GFP_COMP is > used, which sets dtor to COMPOUND_PAGE_DTOR by default. Just hugetlb > and THP set their specific dtors. > > And, it looks __put_compound_page() doesn't check if dtor is NULL or > not at all. > >> >
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