mm: shmem: use proper gfp flags for shmem_writepage()

The shmem_writepage() uses GFP_ATOMIC to allocate swap cache.  GFP_ATOMIC
used to mean __GFP_HIGH, but now it means __GFP_HIGH | __GFP_ATOMIC |
__GFP_KSWAPD_RECLAIM.  However, shmem_writepage() should write out to swap
only in response to memory pressure, so __GFP_KSWAPD_RECLAIM looks useless
since the caller may be kswapd itself or in direct reclaim already.

In addition, XArray node allocations from PF_MEMALLOC contexts could
completely exhaust the page allocator, __GFP_NOMEMALLOC stops emergency
reserves from being allocated.

Here just copy the gfp flags used by add_to_swap().

Hugh:
 "a cleanup to make the two calls look the same when they don't need to
  be different (whereas the call from __read_swap_cache_async() rightly
  uses a lower priority gfp)".

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Yang Shi <[email protected]>
Acked-by: Hugh Dickins <[email protected]>
Cc: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions