Commit 5a03b051 authored by Andrea Arcangeli's avatar Andrea Arcangeli Committed by Linus Torvalds

thp: use compaction in kswapd for GFP_ATOMIC order > 0

This takes advantage of memory compaction to properly generate pages of
order > 0 if regular page reclaim fails and priority level becomes more
severe and we don't reach the proper watermarks.
Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 878aee7d
......@@ -11,6 +11,9 @@
/* The full zone was compacted */
#define COMPACT_COMPLETE 3
#define COMPACT_MODE_DIRECT_RECLAIM 0
#define COMPACT_MODE_KSWAPD 1
#ifdef CONFIG_COMPACTION
extern int sysctl_compact_memory;
extern int sysctl_compaction_handler(struct ctl_table *table, int write,
......@@ -25,7 +28,8 @@ extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
bool sync);
extern unsigned long compaction_suitable(struct zone *zone, int order);
extern unsigned long compact_zone_order(struct zone *zone, int order,
gfp_t gfp_mask, bool sync);
gfp_t gfp_mask, bool sync,
int compact_mode);
/* Do not skip compaction more than 64 times */
#define COMPACT_MAX_DEFER_SHIFT 6
......@@ -70,9 +74,10 @@ static inline unsigned long compaction_suitable(struct zone *zone, int order)
}
static inline unsigned long compact_zone_order(struct zone *zone, int order,
gfp_t gfp_mask, bool sync)
gfp_t gfp_mask, bool sync,
int compact_mode)
{
return 0;
return COMPACT_CONTINUE;
}
static inline void defer_compaction(struct zone *zone)
......
......@@ -42,6 +42,8 @@ struct compact_control {
unsigned int order; /* order a direct compactor needs */
int migratetype; /* MOVABLE, RECLAIMABLE etc */
struct zone *zone;
int compact_mode;
};
static unsigned long release_freepages(struct list_head *freelist)
......@@ -382,10 +384,10 @@ static void update_nr_listpages(struct compact_control *cc)
}
static int compact_finished(struct zone *zone,
struct compact_control *cc)
struct compact_control *cc)
{
unsigned int order;
unsigned long watermark = low_wmark_pages(zone) + (1 << cc->order);
unsigned long watermark;
if (fatal_signal_pending(current))
return COMPACT_PARTIAL;
......@@ -395,12 +397,27 @@ static int compact_finished(struct zone *zone,
return COMPACT_COMPLETE;
/* Compaction run is not finished if the watermark is not met */
if (cc->compact_mode != COMPACT_MODE_KSWAPD)
watermark = low_wmark_pages(zone);
else
watermark = high_wmark_pages(zone);
watermark += (1 << cc->order);
if (!zone_watermark_ok(zone, cc->order, watermark, 0, 0))
return COMPACT_CONTINUE;
if (cc->order == -1)
return COMPACT_CONTINUE;
/*
* Generating only one page of the right order is not enough
* for kswapd, we must continue until we're above the high
* watermark as a pool for high order GFP_ATOMIC allocations
* too.
*/
if (cc->compact_mode == COMPACT_MODE_KSWAPD)
return COMPACT_CONTINUE;
/* Direct compactor: Is a suitable page free? */
for (order = cc->order; order < MAX_ORDER; order++) {
/* Job done if page is free of the right migratetype */
......@@ -514,8 +531,9 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
}
unsigned long compact_zone_order(struct zone *zone,
int order, gfp_t gfp_mask,
bool sync)
int order, gfp_t gfp_mask,
bool sync,
int compact_mode)
{
struct compact_control cc = {
.nr_freepages = 0,
......@@ -524,6 +542,7 @@ unsigned long compact_zone_order(struct zone *zone,
.migratetype = allocflags_to_migratetype(gfp_mask),
.zone = zone,
.sync = sync,
.compact_mode = compact_mode,
};
INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages);
......@@ -569,7 +588,8 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
nodemask) {
int status;
status = compact_zone_order(zone, order, gfp_mask, sync);
status = compact_zone_order(zone, order, gfp_mask, sync,
COMPACT_MODE_DIRECT_RECLAIM);
rc = max(status, rc);
/* If a normal allocation would succeed, stop compacting */
......@@ -600,6 +620,7 @@ static int compact_node(int nid)
.nr_freepages = 0,
.nr_migratepages = 0,
.order = -1,
.compact_mode = COMPACT_MODE_DIRECT_RECLAIM,
};
zone = &pgdat->node_zones[zoneid];
......
......@@ -41,6 +41,7 @@
#include <linux/memcontrol.h>
#include <linux/delayacct.h>
#include <linux/sysctl.h>
#include <linux/compaction.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
......@@ -2382,6 +2383,7 @@ loop_again:
* cause too much scanning of the lower zones.
*/
for (i = 0; i <= end_zone; i++) {
int compaction;
struct zone *zone = pgdat->node_zones + i;
int nr_slab;
......@@ -2411,9 +2413,26 @@ loop_again:
lru_pages);
sc.nr_reclaimed += reclaim_state->reclaimed_slab;
total_scanned += sc.nr_scanned;
compaction = 0;
if (order &&
zone_watermark_ok(zone, 0,
high_wmark_pages(zone),
end_zone, 0) &&
!zone_watermark_ok(zone, order,
high_wmark_pages(zone),
end_zone, 0)) {
compact_zone_order(zone,
order,
sc.gfp_mask, false,
COMPACT_MODE_KSWAPD);
compaction = 1;
}
if (zone->all_unreclaimable)
continue;
if (nr_slab == 0 && !zone_reclaimable(zone))
if (!compaction && nr_slab == 0 &&
!zone_reclaimable(zone))
zone->all_unreclaimable = 1;
/*
* If we've done a decent amount of scanning and
......@@ -2424,15 +2443,6 @@ loop_again:
total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2)
sc.may_writepage = 1;
/*
* Compact the zone for higher orders to reduce
* latencies for higher-order allocations that
* would ordinarily call try_to_compact_pages()
*/
if (sc.order > PAGE_ALLOC_COSTLY_ORDER)
compact_zone_order(zone, sc.order, sc.gfp_mask,
false);
if (!zone_watermark_ok_safe(zone, order,
high_wmark_pages(zone), end_zone, 0)) {
all_zones_ok = 0;
......
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