[RFC 3/9] Make cond_rescheds conditional on __GFP_WAIT

Christoph Lameter
2007-08-14T15:38:31Z

[-- Attachment #1: vmscan_reclaim_resched --]
[-- Type: text/plain, Size: 1594 bytes --]

We cannot reschedule if we are in atomic reclaim. So make
the calls to cond_resched depending on the __GFP_WAIT flag.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

---
mm/vmscan.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

Index: linux-2.6/mm/vmscan.c
===================================================================
--- linux-2.6.orig/mm/vmscan.c 2007-08-14 07:34:18.000000000 -0700
+++ linux-2.6/mm/vmscan.c 2007-08-14 07:34:25.000000000 -0700
@@ -258,6 +258,15 @@ static int may_write_to_queue(struct bac
}

/*
+ * Reschedule if we are not in atomic mode
+ */
+static void reclaim_resched(struct scan_control *sc)
+{
+ if (sc->gfp_mask & __GFP_WAIT)
+ cond_resched();
+}
+
+/*
* We detected a synchronous write error writing a page out. Probably
* -ENOSPC. We need to propagate that into the address_space for a subsequent
* fsync(), msync() or close().
@@ -437,7 +446,7 @@ static unsigned long shrink_page_list(st
int pgactivate = 0;
unsigned long nr_reclaimed = 0;

- cond_resched();
+ reclaim_resched(sc);

pagevec_init(&freed_pvec, 1);
while (!list_empty(page_list)) {
@@ -446,7 +455,7 @@ static unsigned long shrink_page_list(st
int may_enter_fs;
int referenced;

- cond_resched();
+ reclaim_resched(sc);

page = lru_to_page(page_list);
list_del(&page->lru);
@@ -938,7 +947,7 @@ force_reclaim_mapped:
spin_unlock_irq(&zone->lru_lock);

while (!list_empty(&l_hold)) {
- cond_resched();
+ reclaim_resched(sc);
page = lru_to_page(&l_hold);
list_del(&page->lru);
if (page_mapped(page)) {

--