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mm/page_alloc.c: broken deferred calculation
authorPavel Tatashin <pasha.tatashin@oracle.com>
Thu, 16 Nov 2017 01:38:41 +0000 (17:38 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 16 Nov 2017 02:21:07 +0000 (18:21 -0800)
commitd135e5750205a21a212a19dbb05aeb339e2cbea7
treecc96e583458549e9a9385b6e3a8557cf0eddca4f
parent400e22499dd92613821374c8c6c88c7225359980
mm/page_alloc.c: broken deferred calculation

In reset_deferred_meminit() we determine number of pages that must not
be deferred.  We initialize pages for at least 2G of memory, but also
pages for reserved memory in this node.

The reserved memory is determined in this function:
memblock_reserved_memory_within(), which operates over physical
addresses, and returns size in bytes.  However, reset_deferred_meminit()
assumes that that this function operates with pfns, and returns page
count.

The result is that in the best case machine boots slower than expected
due to initializing more pages than needed in single thread, and in the
worst case panics because fewer than needed pages are initialized early.

Link: http://lkml.kernel.org/r/20171021011707.15191-1-pasha.tatashin@oracle.com
Fixes: 864b9a393dcb ("mm: consider memblock reservations for deferred memory initialization sizing")
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/mmzone.h
mm/page_alloc.c