e30825f186
Until now, debug-pagealloc needs extra flags in struct page, so we need to recompile whole source code when we decide to use it. This is really painful, because it takes some time to recompile and sometimes rebuild is not possible due to third party module depending on struct page. So, we can't use this good feature in many cases. Now, we have the page extension feature that allows us to insert extra flags to outside of struct page. This gets rid of third party module issue mentioned above. And, this allows us to determine if we need extra memory for this page extension in boottime. With these property, we can avoid using debug-pagealloc in boottime with low computational overhead in the kernel built with CONFIG_DEBUG_PAGEALLOC. This will help our development process greatly. This patch is the preparation step to achive above goal. debug-pagealloc originally uses extra field of struct page, but, after this patch, it will use field of struct page_ext. Because memory for page_ext is allocated later than initialization of page allocator in CONFIG_SPARSEMEM, we should disable debug-pagealloc feature temporarily until initialization of page_ext. This patch implements this. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Dave Hansen <dave@sr71.net> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Jungsoo Son <jungsoo.son@lge.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
40 lines
1.4 KiB
Plaintext
40 lines
1.4 KiB
Plaintext
config PAGE_EXTENSION
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bool "Extend memmap on extra space for more information on page"
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---help---
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Extend memmap on extra space for more information on page. This
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could be used for debugging features that need to insert extra
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field for every page. This extension enables us to save memory
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by not allocating this extra memory according to boottime
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configuration.
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config DEBUG_PAGEALLOC
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bool "Debug page memory allocations"
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depends on DEBUG_KERNEL
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depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC
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depends on !KMEMCHECK
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select PAGE_EXTENSION
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select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC
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select PAGE_GUARD if ARCH_SUPPORTS_DEBUG_PAGEALLOC
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---help---
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Unmap pages from the kernel linear mapping after free_pages().
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This results in a large slowdown, but helps to find certain types
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of memory corruption.
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For architectures which don't enable ARCH_SUPPORTS_DEBUG_PAGEALLOC,
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fill the pages with poison patterns after free_pages() and verify
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the patterns before alloc_pages(). Additionally,
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this option cannot be enabled in combination with hibernation as
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that would result in incorrect warnings of memory corruption after
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a resume because free pages are not saved to the suspend image.
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config WANT_PAGE_DEBUG_FLAGS
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bool
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config PAGE_POISONING
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bool
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select WANT_PAGE_DEBUG_FLAGS
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config PAGE_GUARD
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bool
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select WANT_PAGE_DEBUG_FLAGS
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