[PATCH] zone_reclaim: additional comments and cleanup
Add some comments to explain how zone reclaim works. And it fixes the following issues: - PF_SWAPWRITE needs to be set for RECLAIM_SWAP to be able to write out pages to swap. Currently RECLAIM_SWAP may not do that. - remove setting nr_reclaimed pages after slab reclaim since the slab shrinking code does not use that and the nr_reclaimed pages is just right for the intended follow up action. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
parent
1742f19fa9
commit
7fb2d46d39
18
mm/vmscan.c
18
mm/vmscan.c
|
@ -1887,6 +1887,7 @@ int zone_reclaim_interval __read_mostly = 30*HZ;
|
|||
*/
|
||||
static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
|
||||
{
|
||||
/* Minimum pages needed in order to stay on node */
|
||||
const unsigned long nr_pages = 1 << order;
|
||||
struct task_struct *p = current;
|
||||
struct reclaim_state reclaim_state;
|
||||
|
@ -1924,9 +1925,12 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
|
|||
|
||||
if (nr_reclaimed < nr_pages && (zone_reclaim_mode & RECLAIM_SLAB)) {
|
||||
/*
|
||||
* shrink_slab does not currently allow us to determine
|
||||
* how many pages were freed in the zone. So we just
|
||||
* shake the slab and then go offnode for a single allocation.
|
||||
* shrink_slab() does not currently allow us to determine how
|
||||
* many pages were freed in this zone. So we just shake the slab
|
||||
* a bit and then go off node for this particular allocation
|
||||
* despite possibly having freed enough memory to allocate in
|
||||
* this zone. If we freed local memory then the next
|
||||
* allocations will be local again.
|
||||
*
|
||||
* shrink_slab will free memory on all zones and may take
|
||||
* a long time.
|
||||
|
@ -1937,8 +1941,14 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
|
|||
p->reclaim_state = NULL;
|
||||
current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE);
|
||||
|
||||
if (nr_reclaimed == 0)
|
||||
if (nr_reclaimed == 0) {
|
||||
/*
|
||||
* We were unable to reclaim enough pages to stay on node. We
|
||||
* now allow off node accesses for a certain time period before
|
||||
* trying again to reclaim pages from the local zone.
|
||||
*/
|
||||
zone->last_unsuccessful_zone_reclaim = jiffies;
|
||||
}
|
||||
|
||||
return nr_reclaimed >= nr_pages;
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue