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-rw-r--r--mm/vmscan.c14
1 files changed, 5 insertions, 9 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index dd544baec..4dbac2008 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -937,21 +937,17 @@ static unsigned long shrink_page_list(struct list_head *page_list,
*
* 2) Global reclaim encounters a page, memcg encounters a
* page that is not marked for immediate reclaim or
- * the caller does not have __GFP_IO. In this case mark
+ * the caller does not have __GFP_FS (or __GFP_IO if it's
+ * simply going to swap, not to fs). In this case mark
* the page for immediate reclaim and continue scanning.
*
- * __GFP_IO is checked because a loop driver thread might
+ * Require may_enter_fs because we would wait on fs, which
+ * may not have submitted IO yet. And the loop driver might
* enter reclaim, and deadlock if it waits on a page for
* which it is needed to do the write (loop masks off
* __GFP_IO|__GFP_FS for this reason); but more thought
* would probably show more reasons.
*
- * Don't require __GFP_FS, since we're not going into the
- * FS, just waiting on its writeback completion. Worryingly,
- * ext4 gfs2 and xfs allocate pages with
- * grab_cache_page_write_begin(,,AOP_FLAG_NOFS), so testing
- * may_enter_fs here is liable to OOM on them.
- *
* 3) memcg encounters a page that is not already marked
* PageReclaim. memcg does not have any dirty pages
* throttling so we could easily OOM just because too many
@@ -968,7 +964,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
/* Case 2 above */
} else if (global_reclaim(sc) ||
- !PageReclaim(page) || !(sc->gfp_mask & __GFP_IO)) {
+ !PageReclaim(page) || !may_enter_fs) {
/*
* This is slightly racy - end_page_writeback()
* might have just cleared PageReclaim, then