vmscan,memcg: reintroduce sc->may_swap
Commit a6dc60f8975ad96d162915e07703a4439c80dcf0 ("vmscan: rename
sc.may_swap to may_unmap") removed the may_swap flag, but memcg had used
it as a flag for "we need to use swap?", as the name indicate.
And in the current implementation, memcg cannot reclaim mapped file
caches when mem+swap hits the limit.
re-introduce may_swap flag and handle it at get_scan_ratio(). This
patch doesn't influence any scan_control users other than memcg.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 99155b7..eac9577 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -63,6 +63,9 @@
/* Can mapped pages be reclaimed? */
int may_unmap;
+ /* Can pages be swapped as part of reclaim? */
+ int may_swap;
+
/* This context's SWAP_CLUSTER_MAX. If freeing memory for
* suspend, we effectively ignore SWAP_CLUSTER_MAX.
* In this context, it doesn't matter that we scan the
@@ -1380,7 +1383,7 @@
struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
/* If we have no swap space, do not bother scanning anon pages. */
- if (nr_swap_pages <= 0) {
+ if (!sc->may_swap || (nr_swap_pages <= 0)) {
percent[0] = 0;
percent[1] = 100;
return;
@@ -1697,6 +1700,7 @@
.may_writepage = !laptop_mode,
.swap_cluster_max = SWAP_CLUSTER_MAX,
.may_unmap = 1,
+ .may_swap = 1,
.swappiness = vm_swappiness,
.order = order,
.mem_cgroup = NULL,
@@ -1717,6 +1721,7 @@
struct scan_control sc = {
.may_writepage = !laptop_mode,
.may_unmap = 1,
+ .may_swap = !noswap,
.swap_cluster_max = SWAP_CLUSTER_MAX,
.swappiness = swappiness,
.order = 0,
@@ -1726,9 +1731,6 @@
};
struct zonelist *zonelist;
- if (noswap)
- sc.may_unmap = 0;
-
sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
zonelist = NODE_DATA(numa_node_id())->node_zonelists;
@@ -1767,6 +1769,7 @@
struct scan_control sc = {
.gfp_mask = GFP_KERNEL,
.may_unmap = 1,
+ .may_swap = 1,
.swap_cluster_max = SWAP_CLUSTER_MAX,
.swappiness = vm_swappiness,
.order = order,
@@ -2298,6 +2301,7 @@
struct scan_control sc = {
.may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE),
.may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP),
+ .may_swap = 1,
.swap_cluster_max = max_t(unsigned long, nr_pages,
SWAP_CLUSTER_MAX),
.gfp_mask = gfp_mask,