Fix up the logic which decides when the caller can dip into page reserves.
- If the caller has realtime scheduling policy, or if the caller cannot run
direct reclaim, then allow the caller to use up to a quarter of the page
reserves.
- If the caller has __GFP_HIGH then allow the caller to use up to half of
the page reserves.
- If the caller has PF_MEMALLOC then the caller can use 100% of the page
reserves.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/mm/page_alloc.c | 20 ++++++++++++++------
1 files changed, 14 insertions(+), 6 deletions(-)
diff -puN mm/page_alloc.c~alloc-pages-priority-tuning mm/page_alloc.c
--- 25/mm/page_alloc.c~alloc-pages-priority-tuning 2004-08-06 02:21:04.452699000 -0700
+++ 25-akpm/mm/page_alloc.c 2004-08-06 02:24:22.580578984 -0700
@@ -609,9 +609,17 @@ __alloc_pages(unsigned int gfp_mask, uns
int i;
int alloc_type;
int do_retry;
+ int can_try_harder;
might_sleep_if(wait);
+ /*
+ * The caller may dip into page reserves a bit more if the caller
+ * cannot run direct reclaim, or is the caller has realtime scheduling
+ * policy
+ */
+ can_try_harder = (unlikely(rt_task(p)) && !in_interrupt()) || !wait;
+
zones = zonelist->zones; /* the list of zones suitable for gfp_mask */
if (unlikely(zones[0] == NULL)) {
@@ -643,9 +651,9 @@ __alloc_pages(unsigned int gfp_mask, uns
for (i = 0; (z = zones[i]) != NULL; i++) {
min = z->pages_min;
if (gfp_mask & __GFP_HIGH)
- min -= min>>1;
- if (unlikely(rt_task(p)) && !in_interrupt())
- min -= min>>2;
+ min /= 2;
+ if (can_try_harder)
+ min -= min / 4;
min += (1<<order) + z->protection[alloc_type];
if (z->free_pages < min)
@@ -686,9 +694,9 @@ rebalance:
for (i = 0; (z = zones[i]) != NULL; i++) {
min = z->pages_min;
if (gfp_mask & __GFP_HIGH)
- min -= min>>1;
- if (unlikely(rt_task(p)) && !in_interrupt())
- min -= min>>2;
+ min /= 2;
+ if (can_try_harder)
+ min -= min / 4;
min += (1<<order) + z->protection[alloc_type];
if (z->free_pages < min)
_