Re: [PATCH -v2] debug-pagealloc: add support for highmem pages
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2011-08-26 00:03:07
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On Thu, 25 Aug 2011 23:14:09 +0900 Akinobu Mita [off-list ref] wrote:
This adds support for highmem pages poisoning and verification to the debug-pagealloc feature for no-architecture support.
Sorry, I had a brainfart. kmap_atomic() internally does the preempt_disable() (actually pagefault_disable()).
--- a/mm/debug-pagealloc.c~debug-pagealloc-add-support-for-highmem-pages-fix
+++ a/mm/debug-pagealloc.c@@ -23,14 +23,11 @@ static inline bool page_poison(struct pa static void poison_page(struct page *page) { - void *addr; + void *addr = kmap_atomic(page); - preempt_disable(); - addr = kmap_atomic(page); set_page_poison(page); memset(addr, PAGE_POISON, PAGE_SIZE); kunmap_atomic(addr); - preempt_enable(); } static void poison_pages(struct page *page, int n)
@@ -82,12 +79,10 @@ static void unpoison_page(struct page *p if (!page_poison(page)) return; - preempt_disable(); addr = kmap_atomic(page); check_poison_mem(addr, PAGE_SIZE); clear_page_poison(page); kunmap_atomic(addr); - preempt_enable(); } static void unpoison_pages(struct page *page, int n)
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