diff options
| author | Christoph Lameter <clameter@engr.sgi.com> | 2006-03-22 00:08:22 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-22 07:54:00 -0800 |
| commit | 7fb2d46d396b2491818f8e43b01049b3234e6c07 (patch) | |
| tree | d5826a4d1c3b1853be20c6049311eb52f1a98360 /mm/vmscan.c | |
| parent | 1742f19fa920cdd6905f0db5898524dde22ab2a4 (diff) | |
[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>
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 2d5d4864de8..c712b946e4f 100644 --- a/mm/vmscan.c +++ b/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; } |