[PATCH 3.14 112/122] mm, compaction: embed migration mode in compact_control

From: Greg Kroah-Hartman
Date: Wed Nov 19 2014 - 16:13:40 EST


3.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: David Rientjes <rientjes@xxxxxxxxxx>

commit e0b9daeb453e602a95ea43853dc12d385558ce1f upstream.

We're going to want to manipulate the migration mode for compaction in the
page allocator, and currently compact_control's sync field is only a bool.

Currently, we only do MIGRATE_ASYNC or MIGRATE_SYNC_LIGHT compaction
depending on the value of this bool. Convert the bool to enum
migrate_mode and pass the migration mode in directly. Later, we'll want
to avoid MIGRATE_SYNC_LIGHT for thp allocations in the pagefault patch to
avoid unnecessary latency.

This also alters compaction triggered from sysfs, either for the entire
system or for a node, to force MIGRATE_SYNC.

[akpm@xxxxxxxxxxxxxxxxxxxx: fix build]
[iamjoonsoo.kim@xxxxxxx: use MIGRATE_SYNC in alloc_contig_range()]
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Suggested-by: Mel Gorman <mgorman@xxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
include/linux/compaction.h | 4 ++--
mm/compaction.c | 36 +++++++++++++++++++-----------------
mm/internal.h | 2 +-
mm/page_alloc.c | 39 +++++++++++++++++----------------------
4 files changed, 39 insertions(+), 42 deletions(-)

--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -22,7 +22,7 @@ extern int sysctl_extfrag_handler(struct
extern int fragmentation_index(struct zone *zone, unsigned int order);
extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
int order, gfp_t gfp_mask, nodemask_t *mask,
- bool sync, bool *contended);
+ enum migrate_mode mode, bool *contended);
extern void compact_pgdat(pg_data_t *pgdat, int order);
extern void reset_isolation_suitable(pg_data_t *pgdat);
extern unsigned long compaction_suitable(struct zone *zone, int order);
@@ -91,7 +91,7 @@ static inline bool compaction_restarting
#else
static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
int order, gfp_t gfp_mask, nodemask_t *nodemask,
- bool sync, bool *contended)
+ enum migrate_mode mode, bool *contended)
{
return COMPACT_CONTINUE;
}
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -161,7 +161,8 @@ static void update_pageblock_skip(struct
return;
if (pfn > zone->compact_cached_migrate_pfn[0])
zone->compact_cached_migrate_pfn[0] = pfn;
- if (cc->sync && pfn > zone->compact_cached_migrate_pfn[1])
+ if (cc->mode != MIGRATE_ASYNC &&
+ pfn > zone->compact_cached_migrate_pfn[1])
zone->compact_cached_migrate_pfn[1] = pfn;
} else {
if (cc->finished_update_free)
@@ -208,7 +209,7 @@ static bool compact_checklock_irqsave(sp
}

/* async aborts if taking too long or contended */
- if (!cc->sync) {
+ if (cc->mode == MIGRATE_ASYNC) {
cc->contended = true;
return false;
}
@@ -473,7 +474,8 @@ isolate_migratepages_range(struct zone *
bool locked = false;
struct page *page = NULL, *valid_page = NULL;
bool set_unsuitable = true;
- const isolate_mode_t mode = (!cc->sync ? ISOLATE_ASYNC_MIGRATE : 0) |
+ const isolate_mode_t mode = (cc->mode == MIGRATE_ASYNC ?
+ ISOLATE_ASYNC_MIGRATE : 0) |
(unevictable ? ISOLATE_UNEVICTABLE : 0);

/*
@@ -483,7 +485,7 @@ isolate_migratepages_range(struct zone *
*/
while (unlikely(too_many_isolated(zone))) {
/* async migration should just abort */
- if (!cc->sync)
+ if (cc->mode == MIGRATE_ASYNC)
return 0;

congestion_wait(BLK_RW_ASYNC, HZ/10);
@@ -548,7 +550,8 @@ isolate_migratepages_range(struct zone *
* the minimum amount of work satisfies the allocation
*/
mt = get_pageblock_migratetype(page);
- if (!cc->sync && !migrate_async_suitable(mt)) {
+ if (cc->mode == MIGRATE_ASYNC &&
+ !migrate_async_suitable(mt)) {
set_unsuitable = false;
goto next_pageblock;
}
@@ -981,6 +984,7 @@ static int compact_zone(struct zone *zon
int ret;
unsigned long start_pfn = zone->zone_start_pfn;
unsigned long end_pfn = zone_end_pfn(zone);
+ const bool sync = cc->mode != MIGRATE_ASYNC;

ret = compaction_suitable(zone, cc->order);
switch (ret) {
@@ -1006,7 +1010,7 @@ static int compact_zone(struct zone *zon
* information on where the scanners should start but check that it
* is initialised by ensuring the values are within zone boundaries.
*/
- cc->migrate_pfn = zone->compact_cached_migrate_pfn[cc->sync];
+ cc->migrate_pfn = zone->compact_cached_migrate_pfn[sync];
cc->free_pfn = zone->compact_cached_free_pfn;
if (cc->free_pfn < start_pfn || cc->free_pfn > end_pfn) {
cc->free_pfn = end_pfn & ~(pageblock_nr_pages-1);
@@ -1040,8 +1044,7 @@ static int compact_zone(struct zone *zon

nr_migrate = cc->nr_migratepages;
err = migrate_pages(&cc->migratepages, compaction_alloc,
- compaction_free, (unsigned long)cc,
- cc->sync ? MIGRATE_SYNC_LIGHT : MIGRATE_ASYNC,
+ compaction_free, (unsigned long)cc, cc->mode,
MR_COMPACTION);
update_nr_listpages(cc);
nr_remaining = cc->nr_migratepages;
@@ -1074,9 +1077,8 @@ out:
return ret;
}

-static unsigned long compact_zone_order(struct zone *zone,
- int order, gfp_t gfp_mask,
- bool sync, bool *contended)
+static unsigned long compact_zone_order(struct zone *zone, int order,
+ gfp_t gfp_mask, enum migrate_mode mode, bool *contended)
{
unsigned long ret;
struct compact_control cc = {
@@ -1085,7 +1087,7 @@ static unsigned long compact_zone_order(
.order = order,
.migratetype = allocflags_to_migratetype(gfp_mask),
.zone = zone,
- .sync = sync,
+ .mode = mode,
};
INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages);
@@ -1107,7 +1109,7 @@ int sysctl_extfrag_threshold = 500;
* @order: The order of the current allocation
* @gfp_mask: The GFP mask of the current allocation
* @nodemask: The allowed nodes to allocate from
- * @sync: Whether migration is synchronous or not
+ * @mode: The migration mode for async, sync light, or sync migration
* @contended: Return value that is true if compaction was aborted due to lock contention
* @page: Optionally capture a free page of the requested order during compaction
*
@@ -1115,7 +1117,7 @@ int sysctl_extfrag_threshold = 500;
*/
unsigned long try_to_compact_pages(struct zonelist *zonelist,
int order, gfp_t gfp_mask, nodemask_t *nodemask,
- bool sync, bool *contended)
+ enum migrate_mode mode, bool *contended)
{
enum zone_type high_zoneidx = gfp_zone(gfp_mask);
int may_enter_fs = gfp_mask & __GFP_FS;
@@ -1140,7 +1142,7 @@ unsigned long try_to_compact_pages(struc
nodemask) {
int status;

- status = compact_zone_order(zone, order, gfp_mask, sync,
+ status = compact_zone_order(zone, order, gfp_mask, mode,
contended);
rc = max(status, rc);

@@ -1190,7 +1192,7 @@ void compact_pgdat(pg_data_t *pgdat, int
{
struct compact_control cc = {
.order = order,
- .sync = false,
+ .mode = MIGRATE_ASYNC,
};

if (!order)
@@ -1203,7 +1205,7 @@ static void compact_node(int nid)
{
struct compact_control cc = {
.order = -1,
- .sync = true,
+ .mode = MIGRATE_SYNC,
.ignore_skip_hint = true,
};

--- a/mm/internal.h
+++ b/mm/internal.h
@@ -134,7 +134,7 @@ struct compact_control {
unsigned long nr_migratepages; /* Number of pages to migrate */
unsigned long free_pfn; /* isolate_freepages search base */
unsigned long migrate_pfn; /* isolate_migratepages search base */
- bool sync; /* Synchronous migration */
+ enum migrate_mode mode; /* Async or sync migration mode */
bool ignore_skip_hint; /* Scan blocks even if marked skip */
bool finished_update_free; /* True when the zone cached pfns are
* no longer being updated
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2246,7 +2246,7 @@ static struct page *
__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist, enum zone_type high_zoneidx,
nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
- int migratetype, bool sync_migration,
+ int migratetype, enum migrate_mode mode,
bool *contended_compaction, bool *deferred_compaction,
unsigned long *did_some_progress)
{
@@ -2260,7 +2260,7 @@ __alloc_pages_direct_compact(gfp_t gfp_m

current->flags |= PF_MEMALLOC;
*did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask,
- nodemask, sync_migration,
+ nodemask, mode,
contended_compaction);
current->flags &= ~PF_MEMALLOC;

@@ -2293,7 +2293,7 @@ __alloc_pages_direct_compact(gfp_t gfp_m
* As async compaction considers a subset of pageblocks, only
* defer if the failure was a sync compaction failure.
*/
- if (sync_migration)
+ if (mode != MIGRATE_ASYNC)
defer_compaction(preferred_zone, order);

cond_resched();
@@ -2306,9 +2306,8 @@ static inline struct page *
__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist, enum zone_type high_zoneidx,
nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
- int migratetype, bool sync_migration,
- bool *contended_compaction, bool *deferred_compaction,
- unsigned long *did_some_progress)
+ int migratetype, enum migrate_mode mode, bool *contended_compaction,
+ bool *deferred_compaction, unsigned long *did_some_progress)
{
return NULL;
}
@@ -2503,7 +2502,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, u
int alloc_flags;
unsigned long pages_reclaimed = 0;
unsigned long did_some_progress;
- bool sync_migration = false;
+ enum migrate_mode migration_mode = MIGRATE_ASYNC;
bool deferred_compaction = false;
bool contended_compaction = false;

@@ -2597,17 +2596,15 @@ rebalance:
* Try direct compaction. The first pass is asynchronous. Subsequent
* attempts after direct reclaim are synchronous
*/
- page = __alloc_pages_direct_compact(gfp_mask, order,
- zonelist, high_zoneidx,
- nodemask,
- alloc_flags, preferred_zone,
- migratetype, sync_migration,
- &contended_compaction,
+ page = __alloc_pages_direct_compact(gfp_mask, order, zonelist,
+ high_zoneidx, nodemask, alloc_flags,
+ preferred_zone, migratetype,
+ migration_mode, &contended_compaction,
&deferred_compaction,
&did_some_progress);
if (page)
goto got_pg;
- sync_migration = true;
+ migration_mode = MIGRATE_SYNC_LIGHT;

/*
* If compaction is deferred for high-order allocations, it is because
@@ -2682,12 +2679,10 @@ rebalance:
* direct reclaim and reclaim/compaction depends on compaction
* being called after reclaim so call directly if necessary
*/
- page = __alloc_pages_direct_compact(gfp_mask, order,
- zonelist, high_zoneidx,
- nodemask,
- alloc_flags, preferred_zone,
- migratetype, sync_migration,
- &contended_compaction,
+ page = __alloc_pages_direct_compact(gfp_mask, order, zonelist,
+ high_zoneidx, nodemask, alloc_flags,
+ preferred_zone, migratetype,
+ migration_mode, &contended_compaction,
&deferred_compaction,
&did_some_progress);
if (page)
@@ -6261,7 +6256,7 @@ static int __alloc_contig_migrate_range(
cc->nr_migratepages -= nr_reclaimed;

ret = migrate_pages(&cc->migratepages, alloc_migrate_target,
- NULL, 0, MIGRATE_SYNC, MR_CMA);
+ NULL, 0, cc->mode, MR_CMA);
}
if (ret < 0) {
putback_movable_pages(&cc->migratepages);
@@ -6300,7 +6295,7 @@ int alloc_contig_range(unsigned long sta
.nr_migratepages = 0,
.order = -1,
.zone = page_zone(pfn_to_page(start)),
- .sync = true,
+ .mode = MIGRATE_SYNC,
.ignore_skip_hint = true,
};
INIT_LIST_HEAD(&cc.migratepages);


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