mm/vmalloc.c: add a schedule point to vmalloc()

It is not uncommon on busy servers to get stuck hundred of ms in
vmalloc() calls (like file descriptor expansions).

Add a cond_resched() to __vmalloc_area_node() to be gentle to
other tasks.

[akpm@linux-foundation.org: only do it for __GFP_WAIT, per David]
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index fdbb116ee669..a3cad905f560 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1602,6 +1602,8 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
                         goto fail;
                 }
                 area->pages[i] = page;
+                if (gfp_mask & __GFP_WAIT)
+                        cond_resched();
         }
 
         if (map_vm_area(area, prot, &pages))