From 4645f06334be1ad0eb61aa182c7999fe51bc1ba6 Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Wed, 11 Feb 2015 15:26:58 -0800 Subject: mm/compaction: change tracepoint format from decimal to hexadecimal To check the range that compaction is working, tracepoint print start/end pfn of zone and start pfn of both scanner with decimal format. Since we manage all pages in order of 2 and it is well represented by hexadecimal, this patch change the tracepoint format from decimal to hexadecimal. This would improve readability. For example, it makes us easily notice whether current scanner try to compact previously attempted pageblock or not. Signed-off-by: Joonsoo Kim Acked-by: Vlastimil Babka Cc: Mel Gorman Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/trace/events/compaction.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/trace/events/compaction.h') diff --git a/include/trace/events/compaction.h b/include/trace/events/compaction.h index c6814b917bdf..1337d9e01e3d 100644 --- a/include/trace/events/compaction.h +++ b/include/trace/events/compaction.h @@ -104,7 +104,7 @@ TRACE_EVENT(mm_compaction_begin, __entry->zone_end = zone_end; ), - TP_printk("zone_start=%lu migrate_start=%lu free_start=%lu zone_end=%lu", + TP_printk("zone_start=0x%lx migrate_start=0x%lx free_start=0x%lx zone_end=0x%lx", __entry->zone_start, __entry->migrate_start, __entry->free_start, -- cgit v1.2.3 From 16c4a097a035c01809aa0c0abd458ca1fe4ff3d0 Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Wed, 11 Feb 2015 15:27:01 -0800 Subject: mm/compaction: enhance tracepoint output for compaction begin/end We now have tracepoint for begin event of compaction and it prints start position of both scanners, but, tracepoint for end event of compaction doesn't print finish position of both scanners. It'd be also useful to know finish position of both scanners so this patch add it. It will help to find odd behavior or problem on compaction internal logic. And mode is added to both begin/end tracepoint output, since according to mode, compaction behavior is quite different. And lastly, status format is changed to string rather than status number for readability. [akpm@linux-foundation.org: fix sparse warning] Signed-off-by: Joonsoo Kim Acked-by: Vlastimil Babka Cc: Mel Gorman Cc: David Rientjes Cc: Dan Carpenter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/compaction.h | 1 + include/trace/events/compaction.h | 49 ++++++++++++++++++++++++++++----------- mm/compaction.c | 15 ++++++++++-- 3 files changed, 49 insertions(+), 16 deletions(-) (limited to 'include/trace/events/compaction.h') diff --git a/include/linux/compaction.h b/include/linux/compaction.h index f2efda2e6ac6..db64cae06530 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -12,6 +12,7 @@ #define COMPACT_PARTIAL 3 /* The full zone was compacted */ #define COMPACT_COMPLETE 4 +/* When adding new state, please change compaction_status_string, too */ /* Used to signal whether compaction detected need_sched() or lock contention */ /* No contention detected */ diff --git a/include/trace/events/compaction.h b/include/trace/events/compaction.h index 1337d9e01e3d..839f6fac921a 100644 --- a/include/trace/events/compaction.h +++ b/include/trace/events/compaction.h @@ -85,46 +85,67 @@ TRACE_EVENT(mm_compaction_migratepages, ); TRACE_EVENT(mm_compaction_begin, - TP_PROTO(unsigned long zone_start, unsigned long migrate_start, - unsigned long free_start, unsigned long zone_end), + TP_PROTO(unsigned long zone_start, unsigned long migrate_pfn, + unsigned long free_pfn, unsigned long zone_end, bool sync), - TP_ARGS(zone_start, migrate_start, free_start, zone_end), + TP_ARGS(zone_start, migrate_pfn, free_pfn, zone_end, sync), TP_STRUCT__entry( __field(unsigned long, zone_start) - __field(unsigned long, migrate_start) - __field(unsigned long, free_start) + __field(unsigned long, migrate_pfn) + __field(unsigned long, free_pfn) __field(unsigned long, zone_end) + __field(bool, sync) ), TP_fast_assign( __entry->zone_start = zone_start; - __entry->migrate_start = migrate_start; - __entry->free_start = free_start; + __entry->migrate_pfn = migrate_pfn; + __entry->free_pfn = free_pfn; __entry->zone_end = zone_end; + __entry->sync = sync; ), - TP_printk("zone_start=0x%lx migrate_start=0x%lx free_start=0x%lx zone_end=0x%lx", + TP_printk("zone_start=0x%lx migrate_pfn=0x%lx free_pfn=0x%lx zone_end=0x%lx, mode=%s", __entry->zone_start, - __entry->migrate_start, - __entry->free_start, - __entry->zone_end) + __entry->migrate_pfn, + __entry->free_pfn, + __entry->zone_end, + __entry->sync ? "sync" : "async") ); TRACE_EVENT(mm_compaction_end, - TP_PROTO(int status), + TP_PROTO(unsigned long zone_start, unsigned long migrate_pfn, + unsigned long free_pfn, unsigned long zone_end, bool sync, + int status), - TP_ARGS(status), + TP_ARGS(zone_start, migrate_pfn, free_pfn, zone_end, sync, status), TP_STRUCT__entry( + __field(unsigned long, zone_start) + __field(unsigned long, migrate_pfn) + __field(unsigned long, free_pfn) + __field(unsigned long, zone_end) + __field(bool, sync) __field(int, status) ), TP_fast_assign( + __entry->zone_start = zone_start; + __entry->migrate_pfn = migrate_pfn; + __entry->free_pfn = free_pfn; + __entry->zone_end = zone_end; + __entry->sync = sync; __entry->status = status; ), - TP_printk("status=%d", __entry->status) + TP_printk("zone_start=0x%lx migrate_pfn=0x%lx free_pfn=0x%lx zone_end=0x%lx, mode=%s status=%s", + __entry->zone_start, + __entry->migrate_pfn, + __entry->free_pfn, + __entry->zone_end, + __entry->sync ? "sync" : "async", + compaction_status_string[__entry->status]) ); #endif /* _TRACE_COMPACTION_H */ diff --git a/mm/compaction.c b/mm/compaction.c index 9c7e6909dd29..66f7c365e888 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -34,6 +34,15 @@ static inline void count_compact_events(enum vm_event_item item, long delta) #endif #if defined CONFIG_COMPACTION || defined CONFIG_CMA +#ifdef CONFIG_TRACEPOINTS +static const char *const compaction_status_string[] = { + "deferred", + "skipped", + "continue", + "partial", + "complete", +}; +#endif #define CREATE_TRACE_POINTS #include @@ -1197,7 +1206,8 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) zone->compact_cached_migrate_pfn[1] = cc->migrate_pfn; } - trace_mm_compaction_begin(start_pfn, cc->migrate_pfn, cc->free_pfn, end_pfn); + trace_mm_compaction_begin(start_pfn, cc->migrate_pfn, + cc->free_pfn, end_pfn, sync); migrate_prep_local(); @@ -1299,7 +1309,8 @@ out: zone->compact_cached_free_pfn = free_pfn; } - trace_mm_compaction_end(ret); + trace_mm_compaction_end(start_pfn, cc->migrate_pfn, + cc->free_pfn, end_pfn, sync, ret); return ret; } -- cgit v1.2.3 From e34d85f0e3c60f7226e5589898b7c7c5cd2a4f02 Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Wed, 11 Feb 2015 15:27:04 -0800 Subject: mm/compaction: print current range where compaction work It'd be useful to know current range where compaction work for detailed analysis. With it, we can know pageblock where we actually scan and isolate, and, how much pages we try in that pageblock and can guess why it doesn't become freepage with pageblock order roughly. Signed-off-by: Joonsoo Kim Acked-by: Vlastimil Babka Cc: Mel Gorman Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/trace/events/compaction.h | 30 +++++++++++++++++++++++------- mm/compaction.c | 9 ++++++--- 2 files changed, 29 insertions(+), 10 deletions(-) (limited to 'include/trace/events/compaction.h') diff --git a/include/trace/events/compaction.h b/include/trace/events/compaction.h index 839f6fac921a..139020b55612 100644 --- a/include/trace/events/compaction.h +++ b/include/trace/events/compaction.h @@ -11,39 +11,55 @@ DECLARE_EVENT_CLASS(mm_compaction_isolate_template, - TP_PROTO(unsigned long nr_scanned, + TP_PROTO( + unsigned long start_pfn, + unsigned long end_pfn, + unsigned long nr_scanned, unsigned long nr_taken), - TP_ARGS(nr_scanned, nr_taken), + TP_ARGS(start_pfn, end_pfn, nr_scanned, nr_taken), TP_STRUCT__entry( + __field(unsigned long, start_pfn) + __field(unsigned long, end_pfn) __field(unsigned long, nr_scanned) __field(unsigned long, nr_taken) ), TP_fast_assign( + __entry->start_pfn = start_pfn; + __entry->end_pfn = end_pfn; __entry->nr_scanned = nr_scanned; __entry->nr_taken = nr_taken; ), - TP_printk("nr_scanned=%lu nr_taken=%lu", + TP_printk("range=(0x%lx ~ 0x%lx) nr_scanned=%lu nr_taken=%lu", + __entry->start_pfn, + __entry->end_pfn, __entry->nr_scanned, __entry->nr_taken) ); DEFINE_EVENT(mm_compaction_isolate_template, mm_compaction_isolate_migratepages, - TP_PROTO(unsigned long nr_scanned, + TP_PROTO( + unsigned long start_pfn, + unsigned long end_pfn, + unsigned long nr_scanned, unsigned long nr_taken), - TP_ARGS(nr_scanned, nr_taken) + TP_ARGS(start_pfn, end_pfn, nr_scanned, nr_taken) ); DEFINE_EVENT(mm_compaction_isolate_template, mm_compaction_isolate_freepages, - TP_PROTO(unsigned long nr_scanned, + + TP_PROTO( + unsigned long start_pfn, + unsigned long end_pfn, + unsigned long nr_scanned, unsigned long nr_taken), - TP_ARGS(nr_scanned, nr_taken) + TP_ARGS(start_pfn, end_pfn, nr_scanned, nr_taken) ); TRACE_EVENT(mm_compaction_migratepages, diff --git a/mm/compaction.c b/mm/compaction.c index 66f7c365e888..b12df9fe10b4 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -430,11 +430,12 @@ isolate_fail: } + trace_mm_compaction_isolate_freepages(*start_pfn, blockpfn, + nr_scanned, total_isolated); + /* Record how far we have got within the block */ *start_pfn = blockpfn; - trace_mm_compaction_isolate_freepages(nr_scanned, total_isolated); - /* * If strict isolation is requested by CMA then check that all the * pages requested were isolated. If there were any failures, 0 is @@ -590,6 +591,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, unsigned long flags = 0; bool locked = false; struct page *page = NULL, *valid_page = NULL; + unsigned long start_pfn = low_pfn; /* * Ensure that there are not too many pages isolated from the LRU @@ -750,7 +752,8 @@ isolate_success: if (low_pfn == end_pfn) update_pageblock_skip(cc, valid_page, nr_isolated, true); - trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated); + trace_mm_compaction_isolate_migratepages(start_pfn, low_pfn, + nr_scanned, nr_isolated); count_compact_events(COMPACTMIGRATE_SCANNED, nr_scanned); if (nr_isolated) -- cgit v1.2.3 From 837d026d560c5ef26abeca0441713d82e4e82cad Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Wed, 11 Feb 2015 15:27:06 -0800 Subject: mm/compaction: more trace to understand when/why compaction start/finish It is not well analyzed that when/why compaction start/finish or not. With these new tracepoints, we can know much more about start/finish reason of compaction. I can find following bug with these tracepoint. http://www.spinics.net/lists/linux-mm/msg81582.html Signed-off-by: Joonsoo Kim Cc: Vlastimil Babka Cc: Mel Gorman Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/compaction.h | 3 ++ include/trace/events/compaction.h | 74 +++++++++++++++++++++++++++++++++++++++ mm/compaction.c | 38 +++++++++++++++++--- 3 files changed, 111 insertions(+), 4 deletions(-) (limited to 'include/trace/events/compaction.h') diff --git a/include/linux/compaction.h b/include/linux/compaction.h index db64cae06530..501d7513aac1 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -12,6 +12,9 @@ #define COMPACT_PARTIAL 3 /* The full zone was compacted */ #define COMPACT_COMPLETE 4 +/* For more detailed tracepoint output */ +#define COMPACT_NO_SUITABLE_PAGE 5 +#define COMPACT_NOT_SUITABLE_ZONE 6 /* When adding new state, please change compaction_status_string, too */ /* Used to signal whether compaction detected need_sched() or lock contention */ diff --git a/include/trace/events/compaction.h b/include/trace/events/compaction.h index 139020b55612..d46535801f63 100644 --- a/include/trace/events/compaction.h +++ b/include/trace/events/compaction.h @@ -164,6 +164,80 @@ TRACE_EVENT(mm_compaction_end, compaction_status_string[__entry->status]) ); +TRACE_EVENT(mm_compaction_try_to_compact_pages, + + TP_PROTO( + int order, + gfp_t gfp_mask, + enum migrate_mode mode), + + TP_ARGS(order, gfp_mask, mode), + + TP_STRUCT__entry( + __field(int, order) + __field(gfp_t, gfp_mask) + __field(enum migrate_mode, mode) + ), + + TP_fast_assign( + __entry->order = order; + __entry->gfp_mask = gfp_mask; + __entry->mode = mode; + ), + + TP_printk("order=%d gfp_mask=0x%x mode=%d", + __entry->order, + __entry->gfp_mask, + (int)__entry->mode) +); + +DECLARE_EVENT_CLASS(mm_compaction_suitable_template, + + TP_PROTO(struct zone *zone, + int order, + int ret), + + TP_ARGS(zone, order, ret), + + TP_STRUCT__entry( + __field(int, nid) + __field(char *, name) + __field(int, order) + __field(int, ret) + ), + + TP_fast_assign( + __entry->nid = zone_to_nid(zone); + __entry->name = (char *)zone->name; + __entry->order = order; + __entry->ret = ret; + ), + + TP_printk("node=%d zone=%-8s order=%d ret=%s", + __entry->nid, + __entry->name, + __entry->order, + compaction_status_string[__entry->ret]) +); + +DEFINE_EVENT(mm_compaction_suitable_template, mm_compaction_finished, + + TP_PROTO(struct zone *zone, + int order, + int ret), + + TP_ARGS(zone, order, ret) +); + +DEFINE_EVENT(mm_compaction_suitable_template, mm_compaction_suitable, + + TP_PROTO(struct zone *zone, + int order, + int ret), + + TP_ARGS(zone, order, ret) +); + #endif /* _TRACE_COMPACTION_H */ /* This part must be outside protection */ diff --git a/mm/compaction.c b/mm/compaction.c index b12df9fe10b4..b6ede459c1bb 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -41,6 +41,8 @@ static const char *const compaction_status_string[] = { "continue", "partial", "complete", + "no_suitable_page", + "not_suitable_zone", }; #endif @@ -1049,7 +1051,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, return cc->nr_migratepages ? ISOLATE_SUCCESS : ISOLATE_NONE; } -static int compact_finished(struct zone *zone, struct compact_control *cc, +static int __compact_finished(struct zone *zone, struct compact_control *cc, const int migratetype) { unsigned int order; @@ -1104,7 +1106,20 @@ static int compact_finished(struct zone *zone, struct compact_control *cc, return COMPACT_PARTIAL; } - return COMPACT_CONTINUE; + return COMPACT_NO_SUITABLE_PAGE; +} + +static int compact_finished(struct zone *zone, struct compact_control *cc, + const int migratetype) +{ + int ret; + + ret = __compact_finished(zone, cc, migratetype); + trace_mm_compaction_finished(zone, cc->order, ret); + if (ret == COMPACT_NO_SUITABLE_PAGE) + ret = COMPACT_CONTINUE; + + return ret; } /* @@ -1114,7 +1129,7 @@ static int compact_finished(struct zone *zone, struct compact_control *cc, * COMPACT_PARTIAL - If the allocation would succeed without compaction * COMPACT_CONTINUE - If compaction should run now */ -unsigned long compaction_suitable(struct zone *zone, int order, +static unsigned long __compaction_suitable(struct zone *zone, int order, int alloc_flags, int classzone_idx) { int fragindex; @@ -1158,11 +1173,24 @@ unsigned long compaction_suitable(struct zone *zone, int order, */ fragindex = fragmentation_index(zone, order); if (fragindex >= 0 && fragindex <= sysctl_extfrag_threshold) - return COMPACT_SKIPPED; + return COMPACT_NOT_SUITABLE_ZONE; return COMPACT_CONTINUE; } +unsigned long compaction_suitable(struct zone *zone, int order, + int alloc_flags, int classzone_idx) +{ + unsigned long ret; + + ret = __compaction_suitable(zone, order, alloc_flags, classzone_idx); + trace_mm_compaction_suitable(zone, order, ret); + if (ret == COMPACT_NOT_SUITABLE_ZONE) + ret = COMPACT_SKIPPED; + + return ret; +} + static int compact_zone(struct zone *zone, struct compact_control *cc) { int ret; @@ -1376,6 +1404,8 @@ unsigned long try_to_compact_pages(gfp_t gfp_mask, unsigned int order, if (!order || !may_enter_fs || !may_perform_io) return COMPACT_SKIPPED; + trace_mm_compaction_try_to_compact_pages(order, gfp_mask, mode); + /* Compact each zone in the list */ for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx, ac->nodemask) { -- cgit v1.2.3 From 24e2716f63e613cf15d3beba3faa0711bcacc427 Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Wed, 11 Feb 2015 15:27:09 -0800 Subject: mm/compaction: add tracepoint to observe behaviour of compaction defer Compaction deferring logic is heavy hammer that block the way to the compaction. It doesn't consider overall system state, so it could prevent user from doing compaction falsely. In other words, even if system has enough range of memory to compact, compaction would be skipped due to compaction deferring logic. This patch add new tracepoint to understand work of deferring logic. This will also help to check compaction success and fail. Signed-off-by: Joonsoo Kim Cc: Vlastimil Babka Cc: Mel Gorman Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/compaction.h | 65 +++-------------------------------- include/trace/events/compaction.h | 56 ++++++++++++++++++++++++++++++ mm/compaction.c | 71 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 132 insertions(+), 60 deletions(-) (limited to 'include/trace/events/compaction.h') diff --git a/include/linux/compaction.h b/include/linux/compaction.h index 501d7513aac1..a014559e4a49 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -44,66 +44,11 @@ extern void reset_isolation_suitable(pg_data_t *pgdat); extern unsigned long compaction_suitable(struct zone *zone, int order, int alloc_flags, int classzone_idx); -/* Do not skip compaction more than 64 times */ -#define COMPACT_MAX_DEFER_SHIFT 6 - -/* - * Compaction is deferred when compaction fails to result in a page - * allocation success. 1 << compact_defer_limit compactions are skipped up - * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT - */ -static inline void defer_compaction(struct zone *zone, int order) -{ - zone->compact_considered = 0; - zone->compact_defer_shift++; - - if (order < zone->compact_order_failed) - zone->compact_order_failed = order; - - if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT) - zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT; -} - -/* Returns true if compaction should be skipped this time */ -static inline bool compaction_deferred(struct zone *zone, int order) -{ - unsigned long defer_limit = 1UL << zone->compact_defer_shift; - - if (order < zone->compact_order_failed) - return false; - - /* Avoid possible overflow */ - if (++zone->compact_considered > defer_limit) - zone->compact_considered = defer_limit; - - return zone->compact_considered < defer_limit; -} - -/* - * Update defer tracking counters after successful compaction of given order, - * which means an allocation either succeeded (alloc_success == true) or is - * expected to succeed. - */ -static inline void compaction_defer_reset(struct zone *zone, int order, - bool alloc_success) -{ - if (alloc_success) { - zone->compact_considered = 0; - zone->compact_defer_shift = 0; - } - if (order >= zone->compact_order_failed) - zone->compact_order_failed = order + 1; -} - -/* Returns true if restarting compaction after many failures */ -static inline bool compaction_restarting(struct zone *zone, int order) -{ - if (order < zone->compact_order_failed) - return false; - - return zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT && - zone->compact_considered >= 1UL << zone->compact_defer_shift; -} +extern void defer_compaction(struct zone *zone, int order); +extern bool compaction_deferred(struct zone *zone, int order); +extern void compaction_defer_reset(struct zone *zone, int order, + bool alloc_success); +extern bool compaction_restarting(struct zone *zone, int order); #else static inline unsigned long try_to_compact_pages(gfp_t gfp_mask, diff --git a/include/trace/events/compaction.h b/include/trace/events/compaction.h index d46535801f63..9a6a3fe0fb51 100644 --- a/include/trace/events/compaction.h +++ b/include/trace/events/compaction.h @@ -238,6 +238,62 @@ DEFINE_EVENT(mm_compaction_suitable_template, mm_compaction_suitable, TP_ARGS(zone, order, ret) ); +#ifdef CONFIG_COMPACTION +DECLARE_EVENT_CLASS(mm_compaction_defer_template, + + TP_PROTO(struct zone *zone, int order), + + TP_ARGS(zone, order), + + TP_STRUCT__entry( + __field(int, nid) + __field(char *, name) + __field(int, order) + __field(unsigned int, considered) + __field(unsigned int, defer_shift) + __field(int, order_failed) + ), + + TP_fast_assign( + __entry->nid = zone_to_nid(zone); + __entry->name = (char *)zone->name; + __entry->order = order; + __entry->considered = zone->compact_considered; + __entry->defer_shift = zone->compact_defer_shift; + __entry->order_failed = zone->compact_order_failed; + ), + + TP_printk("node=%d zone=%-8s order=%d order_failed=%d consider=%u limit=%lu", + __entry->nid, + __entry->name, + __entry->order, + __entry->order_failed, + __entry->considered, + 1UL << __entry->defer_shift) +); + +DEFINE_EVENT(mm_compaction_defer_template, mm_compaction_deferred, + + TP_PROTO(struct zone *zone, int order), + + TP_ARGS(zone, order) +); + +DEFINE_EVENT(mm_compaction_defer_template, mm_compaction_defer_compaction, + + TP_PROTO(struct zone *zone, int order), + + TP_ARGS(zone, order) +); + +DEFINE_EVENT(mm_compaction_defer_template, mm_compaction_defer_reset, + + TP_PROTO(struct zone *zone, int order), + + TP_ARGS(zone, order) +); +#endif + #endif /* _TRACE_COMPACTION_H */ /* This part must be outside protection */ diff --git a/mm/compaction.c b/mm/compaction.c index b6ede459c1bb..b68736c8a1ce 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -124,6 +124,77 @@ static struct page *pageblock_pfn_to_page(unsigned long start_pfn, } #ifdef CONFIG_COMPACTION + +/* Do not skip compaction more than 64 times */ +#define COMPACT_MAX_DEFER_SHIFT 6 + +/* + * Compaction is deferred when compaction fails to result in a page + * allocation success. 1 << compact_defer_limit compactions are skipped up + * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT + */ +void defer_compaction(struct zone *zone, int order) +{ + zone->compact_considered = 0; + zone->compact_defer_shift++; + + if (order < zone->compact_order_failed) + zone->compact_order_failed = order; + + if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT) + zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT; + + trace_mm_compaction_defer_compaction(zone, order); +} + +/* Returns true if compaction should be skipped this time */ +bool compaction_deferred(struct zone *zone, int order) +{ + unsigned long defer_limit = 1UL << zone->compact_defer_shift; + + if (order < zone->compact_order_failed) + return false; + + /* Avoid possible overflow */ + if (++zone->compact_considered > defer_limit) + zone->compact_considered = defer_limit; + + if (zone->compact_considered >= defer_limit) + return false; + + trace_mm_compaction_deferred(zone, order); + + return true; +} + +/* + * Update defer tracking counters after successful compaction of given order, + * which means an allocation either succeeded (alloc_success == true) or is + * expected to succeed. + */ +void compaction_defer_reset(struct zone *zone, int order, + bool alloc_success) +{ + if (alloc_success) { + zone->compact_considered = 0; + zone->compact_defer_shift = 0; + } + if (order >= zone->compact_order_failed) + zone->compact_order_failed = order + 1; + + trace_mm_compaction_defer_reset(zone, order); +} + +/* Returns true if restarting compaction after many failures */ +bool compaction_restarting(struct zone *zone, int order) +{ + if (order < zone->compact_order_failed) + return false; + + return zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT && + zone->compact_considered >= 1UL << zone->compact_defer_shift; +} + /* Returns true if the pageblock should be scanned for pages to isolate. */ static inline bool isolation_suitable(struct compact_control *cc, struct page *page) -- cgit v1.2.3