Cleanup patch from Martin Bligh: convert some loops which want to be
`for' loops into that, and add some commentary.
page_alloc.c | 44 ++++++++++++++++++++------------------------
1 files changed, 20 insertions(+), 24 deletions(-)
--- 2.5.26/mm/page_alloc.c~cleanup-alloc_pages Tue Jul 16 21:46:36 2002
+++ 2.5.26-akpm/mm/page_alloc.c Tue Jul 16 21:46:36 2002
@@ -323,22 +323,23 @@ balance_classzone(zone_t * classzone, un
struct page * __alloc_pages(unsigned int gfp_mask, unsigned int order, zonelist_t *zonelist)
{
unsigned long min;
- zone_t **zone, * classzone;
+ zone_t **zones, *classzone;
struct page * page;
- int freed;
+ int freed, i;
KERNEL_STAT_ADD(pgalloc, 1<<order);
- zone = zonelist->zones;
- classzone = *zone;
- if (classzone == NULL)
+ zones = zonelist->zones; /* the list of zones suitable for gfp_mask */
+ classzone = zones[0];
+ if (classzone == NULL) /* no zones in the zonelist */
return NULL;
+
+ /* Go through the zonelist once, looking for a zone with enough free */
min = 1UL << order;
- for (;;) {
- zone_t *z = *(zone++);
- if (!z)
- break;
+ for (i = 0; zones[i] != NULL; i++) {
+ zone_t *z = zones[i];
+ /* the incremental min is allegedly to discourage fallback */
min += z->pages_low;
if (z->free_pages > min) {
page = rmqueue(z, order);
@@ -349,16 +350,15 @@ struct page * __alloc_pages(unsigned int
classzone->need_balance = 1;
mb();
+ /* we're somewhat low on memory, failed to find what we needed */
if (waitqueue_active(&kswapd_wait))
wake_up_interruptible(&kswapd_wait);
- zone = zonelist->zones;
+ /* Go through the zonelist again, taking __GFP_HIGH into account */
min = 1UL << order;
- for (;;) {
+ for (i = 0; zones[i] != NULL; i++) {
unsigned long local_min;
- zone_t *z = *(zone++);
- if (!z)
- break;
+ zone_t *z = zones[i];
local_min = z->pages_min;
if (gfp_mask & __GFP_HIGH)
@@ -375,11 +375,9 @@ struct page * __alloc_pages(unsigned int
rebalance:
if (current->flags & (PF_MEMALLOC | PF_MEMDIE)) {
- zone = zonelist->zones;
- for (;;) {
- zone_t *z = *(zone++);
- if (!z)
- break;
+ /* go through the zonelist yet again, ignoring mins */
+ for (i = 0; zones[i] != NULL; i++) {
+ zone_t *z = zones[i];
page = rmqueue(z, order);
if (page)
@@ -403,12 +401,10 @@ nopage:
if (page)
return page;
- zone = zonelist->zones;
+ /* go through the zonelist yet one more time */
min = 1UL << order;
- for (;;) {
- zone_t *z = *(zone++);
- if (!z)
- break;
+ for (i = 0; zones[i] != NULL; i++) {
+ zone_t *z = zones[i];
min += z->pages_min;
if (z->free_pages > min) {
.
-
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This archive was generated by hypermail 2b29 : Tue Jul 23 2002 - 22:00:22 EST