[PATCH] swsusp reclaim tweaks 2

Con Kolivas
2006-03-17T06:17:20Z

On Fri, 17 Mar 2006 03:46 pm, Con Kolivas wrote:
> On Fri, 17 Mar 2006 03:28 pm, Con Kolivas wrote:
> > Ok here is a kind of directed memory reclaim for swsusp which is
> > different to ordinary memory reclaim. It reclaims memory in up to 4
> > passes with just shrink_zone, without hooking into balance_pgdat thereby
> > simplifying that function as well.

> It may need to be made more aggressive with another reclaim mapped pass to
> ensure it frees enough memory. That would be trivial to add.

Indeed this was true after a few more suspend resume cycles. Here is a rework
which survived many suspend resume cycles. This worked nicely in combination
with the aggressive swap prefetch tunable being set on resume.

Ok, now please test :) Patch for 2.6.16-rc6-mm1

Cheers,
Con
---
kernel/power/swsusp.c | 10 +--
mm/vmscan.c | 145 ++++++++++++++++++++++++++++----------------------
2 files changed, 87 insertions(+), 68 deletions(-)

Index: linux-2.6.16-rc6-mm1/mm/vmscan.c
===================================================================
--- linux-2.6.16-rc6-mm1.orig/mm/vmscan.c 2006-03-17 16:44:47.000000000 +1100
+++ linux-2.6.16-rc6-mm1/mm/vmscan.c 2006-03-17 16:57:33.000000000 +1100
@@ -74,6 +74,15 @@ struct scan_control {
* In this context, it doesn't matter that we scan the
* whole list at once. */
int swap_cluster_max;
+
+ /*
+ * If we're doing suspend to disk, what pass is this.
+ * 3 = Reclaim from inactive_list only
+ * 2 = Reclaim from active list but don't reclaim mapped
+ * 1 = 2nd pass of type 2
+ * 0 = Reclaim mapped
+ */
+ int suspend;
};

#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
@@ -1345,7 +1354,7 @@ static unsigned long shrink_zone(int pri
*/
zone->nr_scan_active += (zone->nr_active >> priority) + 1;
nr_active = zone->nr_scan_active;
- if (nr_active >= sc->swap_cluster_max)
+ if (nr_active >= sc->swap_cluster_max && sc->suspend < 3)
zone->nr_scan_active = 0;
else
nr_active = 0;
@@ -1402,6 +1411,7 @@ static unsigned long shrink_zones(int pr
unsigned long nr_reclaimed = 0;
int i;

+ sc->suspend = 0;
for (i = 0; zones[i] != NULL; i++) {
struct zone *zone = zones[i];

@@ -1422,7 +1432,12 @@ static unsigned long shrink_zones(int pr
}
return nr_reclaimed;
}
-
+
+#define for_each_priority(priority) \
+ for (priority = DEF_PRIORITY; \
+ priority >= 0; \
+ priority--)
+
/*
* This is the main entry point to direct page reclaim.
*
@@ -1466,7 +1481,7 @@ unsigned long try_to_free_pages(struct z
lru_pages += zone->nr_active + zone->nr_inactive;
}

- for (priority = DEF_PRIORITY; priority >= 0; priority--) {
+ for_each_priority(priority) {
sc.nr_mapped = read_page_state(nr_mapped);
sc.nr_scanned = 0;
if (!priority)
@@ -1516,10 +1531,6 @@ out:
* For kswapd, balance_pgdat() will work across all this node's zones until
* they are all at pages_high.
*
- * If `nr_pages' is non-zero then it is the number of pages which are to be
- * reclaimed, regardless of the zone occupancies. This is a software suspend
- * special.
- *
* Returns the number of pages which were actually freed.
*
* There is special handling here for zones which are full of pinned pages.
@@ -1537,10 +1548,8 @@ out:
* the page allocator fallback scheme to ensure that aging of pages is balanced
* across the zones.
*/
-static unsigned long balance_pgdat(pg_data_t *pgdat, unsigned long nr_pages,
- int order)
+static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
{
- unsigned long to_free = nr_pages;
int all_zones_ok;
int priority;
int i;
@@ -1550,7 +1559,8 @@ static unsigned long balance_pgdat(pg_da
struct scan_control sc = {
.gfp_mask = GFP_KERNEL,
.may_swap = 1,
- .swap_cluster_max = nr_pages ? nr_pages : SWAP_CLUSTER_MAX,
+ .swap_cluster_max = SWAP_CLUSTER_MAX,
+ .suspend = 0,
};

loop_again:
@@ -1567,7 +1577,7 @@ loop_again:
zone->temp_priority = DEF_PRIORITY;
}

- for (priority = DEF_PRIORITY; priority >= 0; priority--) {
+ for_each_priority(priority) {
int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */
unsigned long lru_pages = 0;

@@ -1577,31 +1587,27 @@ loop_again:

all_zones_ok = 1;

- if (nr_pages == 0) {
- /*
- * Scan in the highmem->dma direction for the highest
- * zone which needs scanning
- */
- for (i = pgdat->nr_zones - 1; i >= 0; i--) {
- struct zone *zone = pgdat->node_zones + i;
+ /*
+ * Scan in the highmem->dma direction for the highest
+ * zone which needs scanning
+ */
+ for (i = pgdat->nr_zones - 1; i >= 0; i--) {
+ struct zone *zone = pgdat->node_zones + i;

- if (!populated_zone(zone))
- continue;
+ if (!populated_zone(zone))
+ continue;

- if (zone->all_unreclaimable &&
- priority != DEF_PRIORITY)
- continue;
+ if (zone->all_unreclaimable &&
+ priority != DEF_PRIORITY)
+ continue;

- if (!zone_watermark_ok(zone, order,
- zone->pages_high, 0, 0)) {
- end_zone = i;
- goto scan;
- }
+ if (!zone_watermark_ok(zone, order,
+ zone->pages_high, 0, 0)) {
+ end_zone = i;
+ goto scan;
}
- goto out;
- } else {
- end_zone = pgdat->nr_zones - 1;
}
+ goto out;
scan:
for (i = 0; i <= end_zone; i++) {
struct zone *zone = pgdat->node_zones + i;
@@ -1628,11 +1634,9 @@ scan:
if (zone->all_unreclaimable && priority != DEF_PRIORITY)
continue;

- if (nr_pages == 0) { /* Not software suspend */
- if (!zone_watermark_ok(zone, order,
- zone->pages_high, end_zone, 0))
- all_zones_ok = 0;
- }
+ if (!zone_watermark_ok(zone, order,
+ zone->pages_high, end_zone, 0))
+ all_zones_ok = 0;
zone->temp_priority = priority;
if (zone->prev_priority > priority)
zone->prev_priority = priority;
@@ -1657,8 +1661,6 @@ scan:
total_scanned > nr_reclaimed + nr_reclaimed / 2)
sc.may_writepage = 1;
}
- if (nr_pages && to_free > nr_reclaimed)
- continue; /* swsusp: need to do more work */
if (all_zones_ok)
break; /* kswapd: all done */
/*
@@ -1674,7 +1676,7 @@ scan:
* matches the direct reclaim path behaviour in terms of impact
* on zone->*_priority.
*/
- if ((nr_reclaimed >= SWAP_CLUSTER_MAX) && !nr_pages)
+ if ((nr_reclaimed >= SWAP_CLUSTER_MAX))
break;
}
out:
@@ -1756,7 +1758,7 @@ static int kswapd(void *p)
}
finish_wait(&pgdat->kswapd_wait, &wait);

- balance_pgdat(pgdat, 0, order);
+ balance_pgdat(pgdat, order);
}
return 0;
}
@@ -1790,32 +1792,52 @@ void wakeup_kswapd(struct zone *zone, in
*/
unsigned long shrink_all_memory(unsigned long nr_pages)
{
- pg_data_t *pgdat;
- unsigned long nr_to_free = nr_pages;
unsigned long ret = 0;
- unsigned retry = 2;
- struct reclaim_state reclaim_state = {
- .reclaimed_slab = 0,
+ struct scan_control sc = {
+ .gfp_mask = GFP_KERNEL,
+ .may_swap = 1,
+ .swap_cluster_max = nr_pages,
+ .suspend = 3,
+ .may_writepage = 1,
};

delay_swap_prefetch();

- current->reclaim_state = &reclaim_state;
-repeat:
- for_each_online_pgdat(pgdat) {
- unsigned long freed;
+ do {
+ int priority;

- freed = balance_pgdat(pgdat, nr_to_free, 0);
- ret += freed;
- nr_to_free -= freed;
- if ((long)nr_to_free <= 0)
- break;
- }
- if (retry-- && ret < nr_pages) {
- blk_congestion_wait(WRITE, HZ/5);
- goto repeat;
- }
- current->reclaim_state = NULL;
+ for_each_priority(priority) {
+ struct zone *zone;
+ unsigned long lru_pages = 0;
+
+ for_each_zone(zone) {
+ unsigned long freed;
+
+ if (!populated_zone(zone))
+ continue;
+
+ if (zone->all_unreclaimable &&
+ priority != DEF_PRIORITY)
+ continue;
+
+ lru_pages += zone->nr_active +
+ zone->nr_inactive;
+ /*
+ * shrink_active_list needs this to reclaim
+ * mapped pages
+ */
+ if (!sc.suspend)
+ zone->prev_priority = 0;
+ freed = shrink_zone(priority, zone, &sc);
+ ret += freed;
+ if (ret > nr_pages)
+ goto out;
+ }
+ shrink_slab(0, sc.gfp_mask, lru_pages);
+ blk_congestion_wait(WRITE, HZ / 5);
+ }
+ } while (--sc.suspend >= 0);
+out:
return ret;
}
#endif
@@ -1913,6 +1935,7 @@ static int __zone_reclaim(struct zone *z
.swap_cluster_max = max_t(unsigned long, nr_pages,
SWAP_CLUSTER_MAX),
.gfp_mask = gfp_mask,
+ .suspend = 0,
};

disable_swap_token();
Index: linux-2.6.16-rc6-mm1/kernel/power/swsusp.c
===================================================================
--- linux-2.6.16-rc6-mm1.orig/kernel/power/swsusp.c 2006-03-17 16:44:47.000000000 +1100
+++ linux-2.6.16-rc6-mm1/kernel/power/swsusp.c 2006-03-17 16:45:11.000000000 +1100
@@ -173,9 +173,6 @@ void free_all_swap_pages(int swap, struc
* Notice: all userland should be stopped before it is called, or
* livelock is possible.
*/
-
-#define SHRINK_BITE 10000
-
int swsusp_shrink_memory(void)
{
long size, tmp;
@@ -195,13 +192,12 @@ int swsusp_shrink_memory(void)
if (!is_highmem(zone))
tmp -= zone->free_pages;
if (tmp > 0) {
- tmp = shrink_all_memory(SHRINK_BITE);
+ tmp = shrink_all_memory(tmp);
if (!tmp)
return -ENOMEM;
pages += tmp;
- } else if (size > image_size / PAGE_SIZE) {
- tmp = shrink_all_memory(SHRINK_BITE);
- pages += tmp;
+ if (pages > size)
+ break;
}
printk("\b%c", p[i++%4]);
} while (tmp > 0);