Richard Davies wrote:
> Thank you for your latest patches. I attach my latest perf report for a slow
> boot with all of these applied.
For avoidance of any doubt, there is the combined diff versus 3.6.0-rc5
which I tested:
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 38b42e7..090405d 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1383,10 +1383,8 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans,
qgroup_dirty(fs_info, srcgroup);
}
- if (!inherit) {
- ret = -EINVAL;
+ if (!inherit)
goto unlock;
- }
i_qgroups = (u64 *)(inherit + 1);
for (i = 0; i < inherit->num_qgroups; ++i) {
diff --git a/mm/compaction.c b/mm/compaction.c
index 7fcd3a5..92bae88 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -70,8 +70,7 @@ static bool compact_checklock_irqsave(spinlock_t *lock, unsigned long *flags,
/* async aborts if taking too long or contended */
if (!cc->sync) {
- if (cc->contended)
- *cc->contended = true;
+ cc->contended = true;
return false;
}
@@ -296,8 +295,9 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
/* Time to isolate some pages for migration */
cond_resched();
- spin_lock_irqsave(&zone->lru_lock, flags);
- locked = true;
+ locked = compact_trylock_irqsave(&zone->lru_lock, &flags, cc);
+ if (!locked)
+ return 0;
for (; low_pfn < end_pfn; low_pfn++) {
struct page *page;
@@ -431,17 +431,21 @@ static bool suitable_migration_target(struct page *page)
}
/*
- * Returns the start pfn of the last page block in a zone. This is the starting
- * point for full compaction of a zone. Compaction searches for free pages from
- * the end of each zone, while isolate_freepages_block scans forward inside each
- * page block.
+ * We scan the zone in a circular fashion, starting at
+ * zone->compact_cached_free_pfn. Be careful not to skip if
+ * one compacting thread has just wrapped back to the end of the
+ * zone, but another thread has not.
*/
-static unsigned long start_free_pfn(struct zone *zone)
+static bool compaction_may_skip(struct zone *zone,
+ struct compact_control *cc)
{
- unsigned long free_pfn;
- free_pfn = zone->zone_start_pfn + zone->spanned_pages;
- free_pfn &= ~(pageblock_nr_pages-1);
- return free_pfn;
+ if (!cc->wrapped && zone->compact_cached_free_pfn < cc->start_free_pfn)
+ return true;
+
+ if (cc->wrapped && zone->compact_cached_free_pfn > cc->start_free_pfn)
+ return true;
+
+ return false;
}
/*
@@ -483,6 +487,13 @@ static void isolate_freepages(struct zone *zone,
pfn -= pageblock_nr_pages) {
unsigned long isolated;
+ /*
+ * Skip ahead if another thread is compacting in the area
+ * simultaneously, and has finished with this page block.
+ */
+ if (cc->order > 0 && compaction_may_skip(zone, cc))
+ pfn = min(pfn, zone->compact_cached_free_pfn);
+
if (!pfn_valid(pfn))
continue;
@@ -533,15 +544,7 @@ static void isolate_freepages(struct zone *zone,
*/
if (isolated) {
high_pfn = max(high_pfn, pfn);
-
- /*
- * If the free scanner has wrapped, update
- * compact_cached_free_pfn to point to the highest
- * pageblock with free pages. This reduces excessive
- * scanning of full pageblocks near the end of the
- * zone
- */
- if (cc->order > 0 && cc->wrapped)
+ if (cc->order > 0)
zone->compact_cached_free_pfn = high_pfn;
}
}
@@ -551,11 +554,6 @@ static void isolate_freepages(struct zone *zone,
cc->free_pfn = high_pfn;
cc->nr_freepages = nr_freepages;
-
- /* If compact_cached_free_pfn is reset then set it now */
- if (cc->order > 0 && !cc->wrapped &&
- zone->compact_cached_free_pfn == start_free_pfn(zone))
- zone->compact_cached_free_pfn = high_pfn;
}
/*
@@ -634,7 +632,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
/* Perform the isolation */
low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn);
- if (!low_pfn)
+ if (!low_pfn || cc->contended)
return ISOLATE_ABORT;
cc->migrate_pfn = low_pfn;
@@ -642,6 +640,20 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
return ISOLATE_SUCCESS;
}
+/*
+ * Returns the start pfn of the last page block in a zone. This is the starting
+ * point for full compaction of a zone. Compaction searches for free pages from
+ * the end of each zone, while isolate_freepages_block scans forward inside each
+ * page block.
+ */
+static unsigned long start_free_pfn(struct zone *zone)
+{
+ unsigned long free_pfn;
+ free_pfn = zone->zone_start_pfn + zone->spanned_pages;
+ free_pfn &= ~(pageblock_nr_pages-1);
+ return free_pfn;
+}
+
static int compact_finished(struct zone *zone,
struct compact_control *cc)
{
@@ -787,6 +799,8 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
switch (isolate_migratepages(zone, cc)) {
case ISOLATE_ABORT:
ret = COMPACT_PARTIAL;
+ putback_lru_pages(&cc->migratepages);
+ cc->nr_migratepages = 0;
goto out;
case ISOLATE_NONE:
continue;
@@ -831,6 +845,7 @@ static unsigned long compact_zone_order(struct zone *zone,
int order, gfp_t gfp_mask,
bool sync, bool *contended)
{
+ unsigned long ret;
struct compact_control cc = {
.nr_freepages = 0,
.nr_migratepages = 0,
@@ -838,12 +853,17 @@ static unsigned long compact_zone_order(struct zone *zone,
.migratetype = allocflags_to_migratetype(gfp_mask),
.zone = zone,
.sync = sync,
- .contended = contended,
};
INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages);
- return compact_zone(zone, &cc);
+ ret = compact_zone(zone, &cc);
+
+ VM_BUG_ON(!list_empty(&cc.freepages));
+ VM_BUG_ON(!list_empty(&cc.migratepages));
+
+ *contended = cc.contended;
+ return ret;
}
int sysctl_extfrag_threshold = 500;
diff --git a/mm/internal.h b/mm/internal.h
index b8c91b3..4bd7c0e 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -130,7 +130,7 @@ struct compact_control {
int order; /* order a direct compactor needs */
int migratetype; /* MOVABLE, RECLAIMABLE etc */
struct zone *zone;
- bool *contended; /* True if a lock was contended */
+ bool contended; /* True if a lock was contended */
};
unsigned long
--
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