From 3972f6bb1c6ae1d32dcf2e4ff635d24b77f26dcb Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Thu, 11 Jul 2019 20:55:13 -0700 Subject: mm, debug_pagealloc: use a page type instead of page_ext flag When debug_pagealloc is enabled, we currently allocate the page_ext array to mark guard pages with the PAGE_EXT_DEBUG_GUARD flag. Now that we have the page_type field in struct page, we can use that instead, as guard pages are neither PageSlab nor mapped to userspace. This reduces memory overhead when debug_pagealloc is enabled and there are no other features requiring the page_ext array. Link: http://lkml.kernel.org/r/20190603143451.27353-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka Cc: Joonsoo Kim Cc: Matthew Wilcox Cc: "Kirill A. Shutemov" Cc: Mel Gorman Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/admin-guide/kernel-parameters.txt | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index f1c433daef6b..aa4e7e7b87c2 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -805,12 +805,10 @@ tracking down these problems. debug_pagealloc= - [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this - parameter enables the feature at boot time. In - default, it is disabled. We can avoid allocating huge - chunk of memory for debug pagealloc if we don't enable - it at boot time and the system will work mostly same - with the kernel built without CONFIG_DEBUG_PAGEALLOC. + [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this parameter + enables the feature at boot time. By default, it is + disabled and the system will work mostly the same as a + kernel built without CONFIG_DEBUG_PAGEALLOC. on: enable the feature debugpat [X86] Enable PAT debugging -- cgit v1.2.3-70-g09d2