We are doing the first allocation attempt before calling
current_gfp_context(). But since slab shrinker functions might depend on
__GFP_FS and/or __GFP_IO masking, calling slab shrinker functions from
node_reclaim() from get_page_from_freelist() without calling
current_gfp_context() has possibility of deadlock. Therefore, make sure
that the first memory allocation attempt does not call slab shrinker
functions.
Well, do we want to call node_reclaim() on the first allocation attempt?
If yes, I guess this patch will not be acceptable. But what is correct
flags passed to the first allocation attempt, for currently we ignore
gfp_allowed_mask masking for the first allocation attempt?
Maybe we can tolerate not calling node_reclaim() on the first allocation
attempt, for commit 31a6c1909f51dbe9 ("mm, page_alloc: set alloc_flags
only once in slowpath") says that the fastpath is trying to avoid the
cost of setting up alloc_flags precisely which sounds to me that falling
back to slowpath if node_reclaim() is needed is acceptable?
Signed-off-by: Tetsuo Handa <penguin-ker...@i-love.sakura.ne.jp>
Cc: Michal Hocko <mho...@suse.com>
Cc: Mel Gorman <mgor...@suse.de>
Cc: Vlastimil Babka <vba...@suse.cz>
Cc: David Rientjes <rient...@google.com>
---
mm/page_alloc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6dbc49e..20af138 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4189,7 +4189,8 @@ struct page *
finalise_ac(gfp_mask, order, &ac);
/* First allocation attempt */
- page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
+ page = get_page_from_freelist(alloc_mask & ~__GFP_DIRECT_RECLAIM,
+ order, alloc_flags, &ac);
if (likely(page))
goto out;
--
1.8.3.1
