Messages in this thread | | | From | Jianyu Zhan <> | Date | Tue, 26 Jan 2016 14:39:26 +0800 | Subject | Re: [RFC][PATCH 2/3] mm/page_poison.c: Enable PAGE_POISONING as a separate option |
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On Tue, Jan 26, 2016 at 12:55 AM, Laura Abbott <labbott@fedoraproject.org> wrote: > --- a/mm/debug-pagealloc.c > +++ b/mm/debug-pagealloc.c > @@ -8,11 +8,5 @@ > > void __kernel_map_pages(struct page *page, int numpages, int enable) > { > - if (!page_poisoning_enabled()) > - return; > - > - if (enable) > - unpoison_pages(page, numpages); > - else > - poison_pages(page, numpages); > + kernel_poison_pages(page, numpages, enable); > } > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 63358d9..c733421 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1002,6 +1002,7 @@ static bool free_pages_prepare(struct page *page, unsigned int order) > PAGE_SIZE << order); > } > arch_free_page(page, order); > + kernel_poison_pages(page, 1 << order, 0); > kernel_map_pages(page, 1 << order, 0); > > return true; > @@ -1396,6 +1397,7 @@ static int prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags, > set_page_refcounted(page); > > arch_alloc_page(page, order); > + kernel_poison_pages(page, 1 << order, 1); > kernel_map_pages(page, 1 << order, 1); > kasan_alloc_pages(page, order); >
kernel_map_pages() will fall back to page poisoning scheme for !ARCH_SUPPORTS_DEBUG_PAGEALLOC.
IIUC, calling kernel_poison_pages() before kernel_map_pages() will be equivalent to call kernel_poison_pages() twice?!
Thanks, Jianyu Zhan
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