tree 61b1173bce0ef2738aec4259956c1ecc52280dfa
parent 74033a798f5a5db368126ee6f690111cf019bf7a
author Mel Gorman <mgorman@suse.de> 1435701447 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1435718696 -0700

mm: meminit: finish initialisation of struct pages before basic setup

Waiman Long reported that 24TB machines hit OOM during basic setup when
struct page initialisation was deferred.  One approach is to initialise
memory on demand but it interferes with page allocator paths.  This patch
creates dedicated threads to initialise memory before basic setup.  It
then blocks on a rw_semaphore until completion as a wait_queue and counter
is overkill.  This may be slower to boot but it's simplier overall and
also gets rid of a section mangling which existed so kswapd could do the
initialisation.

[akpm@linux-foundation.org: include rwsem.h, use DECLARE_RWSEM, fix comment, remove unneeded cast]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Waiman Long <waiman.long@hp.com
Cc: Nathan Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Scott Norton <scott.norton@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>