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-rw-r--r--include/linux/compaction.h13
-rw-r--r--mm/compaction.c72
-rw-r--r--mm/internal.h5
-rw-r--r--mm/page_alloc.c28
4 files changed, 17 insertions, 101 deletions
diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index 0980a6ce4436..d4e106b5dc27 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -55,14 +55,6 @@ enum compact_result {
COMPACT_PARTIAL,
};
-/* Used to signal whether compaction detected need_sched() or lock contention */
-/* No contention detected */
-#define COMPACT_CONTENDED_NONE 0
-/* Either need_sched() was true or fatal signal pending */
-#define COMPACT_CONTENDED_SCHED 1
-/* Zone lock or lru_lock was contended in async compaction */
-#define COMPACT_CONTENDED_LOCK 2
-
struct alloc_context; /* in mm/internal.h */
#ifdef CONFIG_COMPACTION
@@ -76,9 +68,8 @@ extern int sysctl_compact_unevictable_allowed;
extern int fragmentation_index(struct zone *zone, unsigned int order);
extern enum compact_result try_to_compact_pages(gfp_t gfp_mask,
- unsigned int order,
- unsigned int alloc_flags, const struct alloc_context *ac,
- enum compact_priority prio, int *contended);
+ unsigned int order, unsigned int alloc_flags,
+ const struct alloc_context *ac, enum compact_priority prio);
extern void compact_pgdat(pg_data_t *pgdat, int order);
extern void reset_isolation_suitable(pg_data_t *pgdat);
extern enum compact_result compaction_suitable(struct zone *zone, int order,
diff --git a/mm/compaction.c b/mm/compaction.c
index 4719a391242f..9affb2908304 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -331,7 +331,7 @@ static bool compact_trylock_irqsave(spinlock_t *lock, unsigned long *flags,
{
if (cc->mode == MIGRATE_ASYNC) {
if (!spin_trylock_irqsave(lock, *flags)) {
- cc->contended = COMPACT_CONTENDED_LOCK;
+ cc->contended = true;
return false;
}
} else {
@@ -365,13 +365,13 @@ static bool compact_unlock_should_abort(spinlock_t *lock,
}
if (fatal_signal_pending(current)) {
- cc->contended = COMPACT_CONTENDED_SCHED;
+ cc->contended = true;
return true;
}
if (need_resched()) {
if (cc->mode == MIGRATE_ASYNC) {
- cc->contended = COMPACT_CONTENDED_SCHED;
+ cc->contended = true;
return true;
}
cond_resched();
@@ -394,7 +394,7 @@ static inline bool compact_should_abort(struct compact_control *cc)
/* async compaction aborts if contended */
if (need_resched()) {
if (cc->mode == MIGRATE_ASYNC) {
- cc->contended = COMPACT_CONTENDED_SCHED;
+ cc->contended = true;
return true;
}
@@ -1619,14 +1619,11 @@ out:
trace_mm_compaction_end(start_pfn, cc->migrate_pfn,
cc->free_pfn, end_pfn, sync, ret);
- if (ret == COMPACT_CONTENDED)
- ret = COMPACT_PARTIAL;
-
return ret;
}
static enum compact_result compact_zone_order(struct zone *zone, int order,
- gfp_t gfp_mask, enum compact_priority prio, int *contended,
+ gfp_t gfp_mask, enum compact_priority prio,
unsigned int alloc_flags, int classzone_idx)
{
enum compact_result ret;
@@ -1650,7 +1647,6 @@ static enum compact_result compact_zone_order(struct zone *zone, int order,
VM_BUG_ON(!list_empty(&cc.freepages));
VM_BUG_ON(!list_empty(&cc.migratepages));
- *contended = cc.contended;
return ret;
}
@@ -1663,23 +1659,18 @@ int sysctl_extfrag_threshold = 500;
* @alloc_flags: The allocation flags of the current allocation
* @ac: The context of current allocation
* @mode: The migration mode for async, sync light, or sync migration
- * @contended: Return value that determines if compaction was aborted due to
- * need_resched() or lock contention
*
* This is the main entry point for direct page compaction.
*/
enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
unsigned int alloc_flags, const struct alloc_context *ac,
- enum compact_priority prio, int *contended)
+ enum compact_priority prio)
{
int may_enter_fs = gfp_mask & __GFP_FS;
int may_perform_io = gfp_mask & __GFP_IO;
struct zoneref *z;
struct zone *zone;
enum compact_result rc = COMPACT_SKIPPED;
- int all_zones_contended = COMPACT_CONTENDED_LOCK; /* init for &= op */
-
- *contended = COMPACT_CONTENDED_NONE;
/* Check if the GFP flags allow compaction */
if (!may_enter_fs || !may_perform_io)
@@ -1691,7 +1682,6 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
ac->nodemask) {
enum compact_result status;
- int zone_contended;
if (compaction_deferred(zone, order)) {
rc = max_t(enum compact_result, COMPACT_DEFERRED, rc);
@@ -1699,14 +1689,8 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
}
status = compact_zone_order(zone, order, gfp_mask, prio,
- &zone_contended, alloc_flags,
- ac_classzone_idx(ac));
+ alloc_flags, ac_classzone_idx(ac));
rc = max(status, rc);
- /*
- * It takes at least one zone that wasn't lock contended
- * to clear all_zones_contended.
- */
- all_zones_contended &= zone_contended;
/* If a normal allocation would succeed, stop compacting */
if (zone_watermark_ok(zone, order, low_wmark_pages(zone),
@@ -1718,59 +1702,29 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
* succeeds in this zone.
*/
compaction_defer_reset(zone, order, false);
- /*
- * It is possible that async compaction aborted due to
- * need_resched() and the watermarks were ok thanks to
- * somebody else freeing memory. The allocation can
- * however still fail so we better signal the
- * need_resched() contention anyway (this will not
- * prevent the allocation attempt).
- */
- if (zone_contended == COMPACT_CONTENDED_SCHED)
- *contended = COMPACT_CONTENDED_SCHED;
- goto break_loop;
+ break;
}
if (prio != COMPACT_PRIO_ASYNC && (status == COMPACT_COMPLETE ||
- status == COMPACT_PARTIAL_SKIPPED)) {
+ status == COMPACT_PARTIAL_SKIPPED))
/*
* We think that allocation won't succeed in this zone
* so we defer compaction there. If it ends up
* succeeding after all, it will be reset.
*/
defer_compaction(zone, order);
- }
/*
* We might have stopped compacting due to need_resched() in
* async compaction, or due to a fatal signal detected. In that
- * case do not try further zones and signal need_resched()
- * contention.
- */
- if ((zone_contended == COMPACT_CONTENDED_SCHED)
- || fatal_signal_pending(current)) {
- *contended = COMPACT_CONTENDED_SCHED;
- goto break_loop;
- }
-
- continue;
-break_loop:
- /*
- * We might not have tried all the zones, so be conservative
- * and assume they are not all lock contended.
+ * case do not try further zones
*/
- all_zones_contended = 0;
- break;
+ if ((prio == COMPACT_PRIO_ASYNC && need_resched())
+ || fatal_signal_pending(current))
+ break;
}
- /*
- * If at least one zone wasn't deferred or skipped, we report if all
- * zones that were tried were lock contended.
- */
- if (rc > COMPACT_INACTIVE && all_zones_contended)
- *contended = COMPACT_CONTENDED_LOCK;
-
return rc;
}
diff --git a/mm/internal.h b/mm/internal.h
index 28932cd6a195..1501304f87a4 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -185,10 +185,7 @@ struct compact_control {
const unsigned int alloc_flags; /* alloc flags of a direct compactor */
const int classzone_idx; /* zone index of a direct compactor */
struct zone *zone;
- int contended; /* Signal need_sched() or lock
- * contention detected during
- * compaction
- */
+ bool contended; /* Signal lock or sched contention */
};
unsigned long
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 26c6fe74f5c5..ea759b935360 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3099,14 +3099,13 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
enum compact_priority prio, enum compact_result *compact_result)
{
struct page *page;
- int contended_compaction;
if (!order)
return NULL;
current->flags |= PF_MEMALLOC;
*compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
- prio, &contended_compaction);
+ prio);
current->flags &= ~PF_MEMALLOC;
if (*compact_result <= COMPACT_INACTIVE)
@@ -3135,24 +3134,6 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
*/
count_vm_event(COMPACTFAIL);
- /*
- * In all zones where compaction was attempted (and not
- * deferred or skipped), lock contention has been detected.
- * For THP allocation we do not want to disrupt the others
- * so we fallback to base pages instead.
- */
- if (contended_compaction == COMPACT_CONTENDED_LOCK)
- *compact_result = COMPACT_CONTENDED;
-
- /*
- * If compaction was aborted due to need_resched(), we do not
- * want to further increase allocation latency, unless it is
- * khugepaged trying to collapse.
- */
- if (contended_compaction == COMPACT_CONTENDED_SCHED
- && !(current->flags & PF_KTHREAD))
- *compact_result = COMPACT_CONTENDED;
-
cond_resched();
return NULL;
@@ -3548,13 +3529,6 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
goto nopage;
/*
- * Compaction is contended so rather back off than cause
- * excessive stalls.
- */
- if (compact_result == COMPACT_CONTENDED)
- goto nopage;
-
- /*
* Looks like reclaim/compaction is worth trying, but
* sync compaction could be very expensive, so keep
* using async compaction.