Commit fe53ca54 authored May 27, 2016 by Yang Shi Committed by Linus Torvalds May 27, 2016

mm: use early_pfn_to_nid in page_ext_init

page_ext_init() checks suitable pages with pfn_to_nid(), but
pfn_to_nid() depends on memmap which will not be setup fully until
page_alloc_init_late() is done.  Use early_pfn_to_nid() instead of
pfn_to_nid() so that page extension could be still used early even
though CONFIG_ DEFERRED_STRUCT_PAGE_INIT is enabled and catch early page
allocation call sites.

Suggested by Joonsoo Kim [1], this fix basically undoes the change
introduced by commit b8f1a75d ("mm: call page_ext_init() after all
struct pages are initialized") and fixes the same problem with a better
approach.

[1] http://lkml.kernel.org/r/CAAmzW4OUmyPwQjvd7QUfc6W1Aic__TyAuH80MLRZNMxKy0-wPQ@mail.gmail.com

Link: http://lkml.kernel.org/r/1464198689-23458-1-git-send-email-yang.shi@linaro.org


Signed-off-by: Yang Shi <yang.shi@linaro.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent f871f191

init/main.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -607,6 +607,7 @@ asmlinkage __visible void __init start_kernel(void)
		initrd_start = 0;
		}
		#endif
		page_ext_init();
		debug_objects_mem_init();
		kmemleak_init();
		setup_per_cpu_pageset();
		@@ -1003,8 +1004,6 @@ static noinline void __init kernel_init_freeable(void)
		sched_init_smp();

		page_alloc_init_late();
		/* Initialize page ext after all struct pages are initializaed */
		page_ext_init();

		do_basic_setup();

mm/page_ext.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -390,8 +390,10 @@ void __init page_ext_init(void)
		* We know some arch can have a nodes layout such as
		* -------------pfn-------------->
		* N0 \| N1 \| N2 \| N0 \| N1 \| N2\|....
		*
		* Take into account DEFERRED_STRUCT_PAGE_INIT.
		*/
		if (pfn_to_nid(pfn) != nid)
		if (early_pfn_to_nid(pfn) != nid)
		continue;
		if (init_section_page_ext(pfn, nid))
		goto oom;

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