From 65190cff3cc108b72e42cce67ed8b73dbad6b731 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Wed, 22 Feb 2017 15:42:03 -0800 Subject: [PATCH] oom, trace: add compaction retry tracepoint Higher order requests oom debugging is currently quite hard. We do have some compaction points which can tell us how the compaction is operating but there is no trace point to tell us about compaction retry logic. This patch adds a one which will have the following format bash-3126 [001] .... 1498.220001: compact_retry: order=9 priority=COMPACT_PRIO_SYNC_LIGHT compaction_result=withdrawn retries=0 max_retries=16 should_retry=0 we can see that the order 9 request is not retried even though we are in the highest compaction priority mode becase the last compaction attempt was withdrawn. This means that compaction_zonelist_suitable must have returned false and there is no suitable zone to compact for this request and so no need to retry further. another example would be <...>-3137 [001] .... 81.501689: compact_retry: order=9 priority=COMPACT_PRIO_SYNC_LIGHT compaction_result=failed retries=0 max_retries=16 should_retry=0 in this case the order-9 compaction failed to find any suitable block. We do not retry anymore because this is a costly request and those do not go below COMPACT_PRIO_SYNC_LIGHT priority. Link: http://lkml.kernel.org/r/20161220130135.15719-4-mhocko@kernel.org Signed-off-by: Michal Hocko Acked-by: Vlastimil Babka Cc: David Rientjes Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/trace/events/mmflags.h | 26 +++++++++++++++++++++++ include/trace/events/oom.h | 39 ++++++++++++++++++++++++++++++++++ mm/page_alloc.c | 22 +++++++++++++------ 3 files changed, 81 insertions(+), 6 deletions(-) diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h index 75ed3220ede2..91554faed17e 100644 --- a/include/trace/events/mmflags.h +++ b/include/trace/events/mmflags.h @@ -186,8 +186,32 @@ IF_HAVE_VM_SOFTDIRTY(VM_SOFTDIRTY, "softdirty" ) \ EM( COMPACT_NO_SUITABLE_PAGE, "no_suitable_page") \ EM( COMPACT_NOT_SUITABLE_ZONE, "not_suitable_zone") \ EMe(COMPACT_CONTENDED, "contended") + +/* High-level compaction status feedback */ +#define COMPACTION_FAILED 1 +#define COMPACTION_WITHDRAWN 2 +#define COMPACTION_PROGRESS 3 + +#define compact_result_to_feedback(result) \ +({ \ + enum compact_result __result = result; \ + (compaction_failed(__result)) ? COMPACTION_FAILED : \ + (compaction_withdrawn(__result)) ? COMPACTION_WITHDRAWN : COMPACTION_PROGRESS; \ +}) + +#define COMPACTION_FEEDBACK \ + EM(COMPACTION_FAILED, "failed") \ + EM(COMPACTION_WITHDRAWN, "withdrawn") \ + EMe(COMPACTION_PROGRESS, "progress") + +#define COMPACTION_PRIORITY \ + EM(COMPACT_PRIO_SYNC_FULL, "COMPACT_PRIO_SYNC_FULL") \ + EM(COMPACT_PRIO_SYNC_LIGHT, "COMPACT_PRIO_SYNC_LIGHT") \ + EMe(COMPACT_PRIO_ASYNC, "COMPACT_PRIO_ASYNC") #else #define COMPACTION_STATUS +#define COMPACTION_PRIORITY +#define COMPACTION_FEEDBACK #endif #ifdef CONFIG_ZONE_DMA @@ -225,6 +249,8 @@ IF_HAVE_VM_SOFTDIRTY(VM_SOFTDIRTY, "softdirty" ) \ #define EMe(a, b) TRACE_DEFINE_ENUM(a); COMPACTION_STATUS +COMPACTION_PRIORITY +COMPACTION_FEEDBACK ZONE_TYPE /* diff --git a/include/trace/events/oom.h b/include/trace/events/oom.h index 9160da7a26a0..38baeb27221a 100644 --- a/include/trace/events/oom.h +++ b/include/trace/events/oom.h @@ -69,6 +69,45 @@ TRACE_EVENT(reclaim_retry_zone, __entry->no_progress_loops, __entry->wmark_check) ); + +#ifdef CONFIG_COMPACTION +TRACE_EVENT(compact_retry, + + TP_PROTO(int order, + enum compact_priority priority, + enum compact_result result, + int retries, + int max_retries, + bool ret), + + TP_ARGS(order, priority, result, retries, max_retries, ret), + + TP_STRUCT__entry( + __field( int, order) + __field( int, priority) + __field( int, result) + __field( int, retries) + __field( int, max_retries) + __field( bool, ret) + ), + + TP_fast_assign( + __entry->order = order; + __entry->priority = priority; + __entry->result = compact_result_to_feedback(result); + __entry->retries = retries; + __entry->max_retries = max_retries; + __entry->ret = ret; + ), + + TP_printk("order=%d priority=%s compaction_result=%s retries=%d max_retries=%d should_retry=%d", + __entry->order, + __print_symbolic(__entry->priority, COMPACTION_PRIORITY), + __print_symbolic(__entry->result, COMPACTION_FEEDBACK), + __entry->retries, __entry->max_retries, + __entry->ret) +); +#endif /* CONFIG_COMPACTION */ #endif /* This part must be outside protection */ diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d20f8c3139bb..05c0a59323bd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3197,6 +3197,9 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, { int max_retries = MAX_COMPACT_RETRIES; int min_priority; + bool ret = false; + int retries = *compaction_retries; + enum compact_priority priority = *compact_priority; if (!order) return false; @@ -3218,8 +3221,10 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, * But do not retry if the given zonelist is not suitable for * compaction. */ - if (compaction_withdrawn(compact_result)) - return compaction_zonelist_suitable(ac, order, alloc_flags); + if (compaction_withdrawn(compact_result)) { + ret = compaction_zonelist_suitable(ac, order, alloc_flags); + goto out; + } /* * !costly requests are much more important than __GFP_REPEAT @@ -3231,8 +3236,10 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, */ if (order > PAGE_ALLOC_COSTLY_ORDER) max_retries /= 4; - if (*compaction_retries <= max_retries) - return true; + if (*compaction_retries <= max_retries) { + ret = true; + goto out; + } /* * Make sure there are attempts at the highest priority if we exhausted @@ -3241,12 +3248,15 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, check_priority: min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ? MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY; + if (*compact_priority > min_priority) { (*compact_priority)--; *compaction_retries = 0; - return true; + ret = true; } - return false; +out: + trace_compact_retry(order, priority, compact_result, retries, max_retries, ret); + return ret; } #else static inline struct page *