tree 2510dd69af412e5ba85db10290d49806b88603bd
parent 2c434f622e5075e30b62829fa25dc36f56141594
author Minchan Kim <minchan@google.com> 1575165509 -0800
committer Suren Baghdasaryan <surenb@google.com> 1579822994 -0800

UPSTREAM: mm/page_io.c: annotate refault stalls from swap_readpage

If a block device supports rw_page operation, it doesn't submit bios so
the annotation in submit_bio() for refault stall doesn't work.  It
happens with zram in android, especially swap read path which could
consume CPU cycle for decompress.  It is also a problem for zswap which
uses frontswap.

Annotate swap_readpage() to account the synchronous IO overhead to
prevent underreport memory pressure.

[akpm@linux-foundation.org: add comment, per Johannes]
Link: http://lkml.kernel.org/r/20191010152134.38545-1-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

(cherry picked from commit 937790699be9c8100e5358625e7dfa8b32bd33f2)
Bug: 142418748
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: Idf6af841dfc07ded7039f84f8a533e2a3f6eddfc