summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
Diffstat
-rw-r--r--mm/compaction.c10
-rw-r--r--mm/internal.h1
-rw-r--r--mm/vmscan.c147
3 files changed, 54 insertions, 104 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index 5b2bfbaa821a..ccf97b02b85f 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1191,11 +1191,11 @@ static int __compact_finished(struct zone *zone, struct compact_control *cc,
/*
* Mark that the PG_migrate_skip information should be cleared
- * by kswapd when it goes to sleep. kswapd does not set the
+ * by kswapd when it goes to sleep. kcompactd does not set the
* flag itself as the decision to be clear should be directly
* based on an allocation request.
*/
- if (!current_is_kswapd())
+ if (cc->direct_compaction)
zone->compact_blockskip_flush = true;
return COMPACT_COMPLETE;
@@ -1338,10 +1338,9 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
/*
* Clear pageblock skip if there were failures recently and compaction
- * is about to be retried after being deferred. kswapd does not do
- * this reset as it'll reset the cached information when going to sleep.
+ * is about to be retried after being deferred.
*/
- if (compaction_restarting(zone, cc->order) && !current_is_kswapd())
+ if (compaction_restarting(zone, cc->order))
__reset_isolation_suitable(zone);
/*
@@ -1477,6 +1476,7 @@ static unsigned long compact_zone_order(struct zone *zone, int order,
.mode = mode,
.alloc_flags = alloc_flags,
.classzone_idx = classzone_idx,
+ .direct_compaction = true,
};
INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages);
diff --git a/mm/internal.h b/mm/internal.h
index b95952c2faec..4042a8a05672 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -172,6 +172,7 @@ struct compact_control {
unsigned long last_migrated_pfn;/* Not yet flushed page being freed */
enum migrate_mode mode; /* Async or sync migration mode */
bool ignore_skip_hint; /* Scan blocks even if marked skip */
+ bool direct_compaction; /* False from kcompactd or /proc/... */
int order; /* order a direct compactor needs */
const gfp_t gfp_mask; /* gfp mask of a direct compactor */
const int alloc_flags; /* alloc flags of a direct compactor */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 5dcc71140108..f87cfaa955a8 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2968,18 +2968,23 @@ static void age_active_anon(struct zone *zone, struct scan_control *sc)
} while (memcg);
}
-static bool zone_balanced(struct zone *zone, int order,
- unsigned long balance_gap, int classzone_idx)
+static bool zone_balanced(struct zone *zone, int order, bool highorder,
+ unsigned long balance_gap, int classzone_idx)
{
- if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone) +
- balance_gap, classzone_idx))
- return false;
+ unsigned long mark = high_wmark_pages(zone) + balance_gap;
- if (IS_ENABLED(CONFIG_COMPACTION) && order && compaction_suitable(zone,
- order, 0, classzone_idx) == COMPACT_SKIPPED)
- return false;
+ /*
+ * When checking from pgdat_balanced(), kswapd should stop and sleep
+ * when it reaches the high order-0 watermark and let kcompactd take
+ * over. Other callers such as wakeup_kswapd() want to determine the
+ * true high-order watermark.
+ */
+ if (IS_ENABLED(CONFIG_COMPACTION) && !highorder) {
+ mark += (1UL << order);
+ order = 0;
+ }
- return true;
+ return zone_watermark_ok_safe(zone, order, mark, classzone_idx);
}
/*
@@ -3029,7 +3034,7 @@ static bool pgdat_balanced(pg_data_t *pgdat, int order, int classzone_idx)
continue;
}
- if (zone_balanced(zone, order, 0, i))
+ if (zone_balanced(zone, order, false, 0, i))
balanced_pages += zone->managed_pages;
else if (!order)
return false;
@@ -3083,10 +3088,8 @@ static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining,
*/
static bool kswapd_shrink_zone(struct zone *zone,
int classzone_idx,
- struct scan_control *sc,
- unsigned long *nr_attempted)
+ struct scan_control *sc)
{
- int testorder = sc->order;
unsigned long balance_gap;
bool lowmem_pressure;
@@ -3094,17 +3097,6 @@ static bool kswapd_shrink_zone(struct zone *zone,
sc->nr_to_reclaim = max(SWAP_CLUSTER_MAX, high_wmark_pages(zone));
/*
- * Kswapd reclaims only single pages with compaction enabled. Trying
- * too hard to reclaim until contiguous free pages have become
- * available can hurt performance by evicting too much useful data
- * from memory. Do not reclaim more than needed for compaction.
- */
- if (IS_ENABLED(CONFIG_COMPACTION) && sc->order &&
- compaction_suitable(zone, sc->order, 0, classzone_idx)
- != COMPACT_SKIPPED)
- testorder = 0;
-
- /*
* We put equal pressure on every zone, unless one zone has way too
* many pages free already. The "too many pages" is defined as the
* high wmark plus a "gap" where the gap is either the low
@@ -3118,15 +3110,12 @@ static bool kswapd_shrink_zone(struct zone *zone,
* reclaim is necessary
*/
lowmem_pressure = (buffer_heads_over_limit && is_highmem(zone));
- if (!lowmem_pressure && zone_balanced(zone, testorder,
+ if (!lowmem_pressure && zone_balanced(zone, sc->order, false,
balance_gap, classzone_idx))
return true;
shrink_zone(zone, sc, zone_idx(zone) == classzone_idx);
- /* Account for the number of pages attempted to reclaim */
- *nr_attempted += sc->nr_to_reclaim;
-
clear_bit(ZONE_WRITEBACK, &zone->flags);
/*
@@ -3136,7 +3125,7 @@ static bool kswapd_shrink_zone(struct zone *zone,
* waits.
*/
if (zone_reclaimable(zone) &&
- zone_balanced(zone, testorder, 0, classzone_idx)) {
+ zone_balanced(zone, sc->order, false, 0, classzone_idx)) {
clear_bit(ZONE_CONGESTED, &zone->flags);
clear_bit(ZONE_DIRTY, &zone->flags);
}
@@ -3148,7 +3137,7 @@ static bool kswapd_shrink_zone(struct zone *zone,
* For kswapd, balance_pgdat() will work across all this node's zones until
* they are all at high_wmark_pages(zone).
*
- * Returns the final order kswapd was reclaiming at
+ * Returns the highest zone idx kswapd was reclaiming at
*
* There is special handling here for zones which are full of pinned pages.
* This can happen if the pages are all mlocked, or if they are all used by
@@ -3165,8 +3154,7 @@ static bool kswapd_shrink_zone(struct zone *zone,
* interoperates with 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, int order,
- int *classzone_idx)
+static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
{
int i;
int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */
@@ -3183,9 +3171,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
count_vm_event(PAGEOUTRUN);
do {
- unsigned long nr_attempted = 0;
bool raise_priority = true;
- bool pgdat_needs_compaction = (order > 0);
sc.nr_reclaimed = 0;
@@ -3220,7 +3206,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
break;
}
- if (!zone_balanced(zone, order, 0, 0)) {
+ if (!zone_balanced(zone, order, false, 0, 0)) {
end_zone = i;
break;
} else {
@@ -3236,24 +3222,6 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
if (i < 0)
goto out;
- for (i = 0; i <= end_zone; i++) {
- struct zone *zone = pgdat->node_zones + i;
-
- if (!populated_zone(zone))
- continue;
-
- /*
- * If any zone is currently balanced then kswapd will
- * not call compaction as it is expected that the
- * necessary pages are already available.
- */
- if (pgdat_needs_compaction &&
- zone_watermark_ok(zone, order,
- low_wmark_pages(zone),
- *classzone_idx, 0))
- pgdat_needs_compaction = false;
- }
-
/*
* If we're getting trouble reclaiming, start doing writepage
* even in laptop mode.
@@ -3297,8 +3265,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
* that that high watermark would be met at 100%
* efficiency.
*/
- if (kswapd_shrink_zone(zone, end_zone,
- &sc, &nr_attempted))
+ if (kswapd_shrink_zone(zone, end_zone, &sc))
raise_priority = false;
}
@@ -3311,49 +3278,29 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
pfmemalloc_watermark_ok(pgdat))
wake_up_all(&pgdat->pfmemalloc_wait);
- /*
- * Fragmentation may mean that the system cannot be rebalanced
- * for high-order allocations in all zones. If twice the
- * allocation size has been reclaimed and the zones are still
- * not balanced then recheck the watermarks at order-0 to
- * prevent kswapd reclaiming excessively. Assume that a
- * process requested a high-order can direct reclaim/compact.
- */
- if (order && sc.nr_reclaimed >= 2UL << order)
- order = sc.order = 0;
-
/* Check if kswapd should be suspending */
if (try_to_freeze() || kthread_should_stop())
break;
/*
- * Compact if necessary and kswapd is reclaiming at least the
- * high watermark number of pages as requsted
- */
- if (pgdat_needs_compaction && sc.nr_reclaimed > nr_attempted)
- compact_pgdat(pgdat, order);
-
- /*
* Raise priority if scanning rate is too low or there was no
* progress in reclaiming pages
*/
if (raise_priority || !sc.nr_reclaimed)
sc.priority--;
} while (sc.priority >= 1 &&
- !pgdat_balanced(pgdat, order, *classzone_idx));
+ !pgdat_balanced(pgdat, order, classzone_idx));
out:
/*
- * Return the order we were reclaiming at so prepare_kswapd_sleep()
- * makes a decision on the order we were last reclaiming at. However,
- * if another caller entered the allocator slow path while kswapd
- * was awake, order will remain at the higher level
+ * Return the highest zone idx we were reclaiming at so
+ * prepare_kswapd_sleep() makes the same decisions as here.
*/
- *classzone_idx = end_zone;
- return order;
+ return end_zone;
}
-static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx)
+static void kswapd_try_to_sleep(pg_data_t *pgdat, int order,
+ int classzone_idx, int balanced_classzone_idx)
{
long remaining = 0;
DEFINE_WAIT(wait);
@@ -3364,7 +3311,8 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx)
prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
/* Try to sleep for a short interval */
- if (prepare_kswapd_sleep(pgdat, order, remaining, classzone_idx)) {
+ if (prepare_kswapd_sleep(pgdat, order, remaining,
+ balanced_classzone_idx)) {
remaining = schedule_timeout(HZ/10);
finish_wait(&pgdat->kswapd_wait, &wait);
prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
@@ -3374,7 +3322,8 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx)
* After a short sleep, check if it was a premature sleep. If not, then
* go fully to sleep until explicitly woken up.
*/
- if (prepare_kswapd_sleep(pgdat, order, remaining, classzone_idx)) {
+ if (prepare_kswapd_sleep(pgdat, order, remaining,
+ balanced_classzone_idx)) {
trace_mm_vmscan_kswapd_sleep(pgdat->node_id);
/*
@@ -3395,6 +3344,12 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx)
*/
reset_isolation_suitable(pgdat);
+ /*
+ * We have freed the memory, now we should compact it to make
+ * allocation of the requested order possible.
+ */
+ wakeup_kcompactd(pgdat, order, classzone_idx);
+
if (!kthread_should_stop())
schedule();
@@ -3424,7 +3379,6 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx)
static int kswapd(void *p)
{
unsigned long order, new_order;
- unsigned balanced_order;
int classzone_idx, new_classzone_idx;
int balanced_classzone_idx;
pg_data_t *pgdat = (pg_data_t*)p;
@@ -3457,23 +3411,19 @@ static int kswapd(void *p)
set_freezable();
order = new_order = 0;
- balanced_order = 0;
classzone_idx = new_classzone_idx = pgdat->nr_zones - 1;
balanced_classzone_idx = classzone_idx;
for ( ; ; ) {
bool ret;
/*
- * If the last balance_pgdat was unsuccessful it's unlikely a
- * new request of a similar or harder type will succeed soon
- * so consider going to sleep on the basis we reclaimed at
+ * While we were reclaiming, there might have been another
+ * wakeup, so check the values.
*/
- if (balanced_order == new_order) {
- new_order = pgdat->kswapd_max_order;
- new_classzone_idx = pgdat->classzone_idx;
- pgdat->kswapd_max_order = 0;
- pgdat->classzone_idx = pgdat->nr_zones - 1;
- }
+ new_order = pgdat->kswapd_max_order;
+ new_classzone_idx = pgdat->classzone_idx;
+ pgdat->kswapd_max_order = 0;
+ pgdat->classzone_idx = pgdat->nr_zones - 1;
if (order < new_order || classzone_idx > new_classzone_idx) {
/*
@@ -3483,7 +3433,7 @@ static int kswapd(void *p)
order = new_order;
classzone_idx = new_classzone_idx;
} else {
- kswapd_try_to_sleep(pgdat, balanced_order,
+ kswapd_try_to_sleep(pgdat, order, classzone_idx,
balanced_classzone_idx);
order = pgdat->kswapd_max_order;
classzone_idx = pgdat->classzone_idx;
@@ -3503,9 +3453,8 @@ static int kswapd(void *p)
*/
if (!ret) {
trace_mm_vmscan_kswapd_wake(pgdat->node_id, order);
- balanced_classzone_idx = classzone_idx;
- balanced_order = balance_pgdat(pgdat, order,
- &balanced_classzone_idx);
+ balanced_classzone_idx = balance_pgdat(pgdat, order,
+ classzone_idx);
}
}
@@ -3535,7 +3484,7 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
}
if (!waitqueue_active(&pgdat->kswapd_wait))
return;
- if (zone_balanced(zone, order, 0, 0))
+ if (zone_balanced(zone, order, true, 0, 0))
return;
trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, zone_idx(zone), order);
generated by cgit (git 2.34.1) at 2024-05-28 08:34:56 +0000