Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [RFC][PATCH 2/3] mm/page_poison.c: Enable PAGE_POISONING as a separate option | From | Laura Abbott <> | Date | Tue, 26 Jan 2016 12:27:35 -0800 |
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On 01/25/2016 10:39 PM, Jianyu Zhan wrote: > 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?! > >
Yes, you are absolutely right. In the !ARCH_SUPPORTS_DEBUG_PAGEALLOC case we shouldn't need to do anything in kernel_map_pages.
> > > Thanks, > Jianyu Zhan >
Thanks, Laura
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