From 4f1a04487423c0ccc6316b28dde7f65414560fba Mon Sep 17 00:00:00 2001 From: "Joel Fernandes (Google)" Date: Tue, 1 Oct 2019 13:28:17 -0400 Subject: [PATCH] UPSTREAM: mm: emit tracepoint when RSS changes MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Useful to track how RSS is changing per TGID to detect spikes in RSS and memory hogs. Several Android teams have been using this patch in various kernel trees for half a year now. Many reported to me it is really useful so I'm posting it upstream. Initial patch developed by Tim Murray. Changes I made from original patch: o Prevent any additional space consumed by mm_struct. Regarding the fact that the RSS may change too often thus flooding the traces - note that, there is some "hysterisis" with this already. That is - We update the counter only if we receive 64 page faults due to SPLIT_RSS_ACCOUNTING. However, during zapping or copying of pte range, the RSS is updated immediately which can become noisy/flooding. In a previous discussion, we agreed that BPF or ftrace can be used to rate limit the signal if this becomes an issue. Also note that I added wrappers to trace_rss_stat to prevent compiler errors where linux/mm.h is included from tracing code, causing errors such as: CC kernel/trace/power-traces.o In file included from ./include/trace/define_trace.h:102, from ./include/trace/events/kmem.h:342, from ./include/linux/mm.h:31, from ./include/linux/ring_buffer.h:5, from ./include/linux/trace_events.h:6, from ./include/trace/events/power.h:12, from kernel/trace/power-traces.c:15: ./include/trace/trace_events.h:113:22: error: field ‘ent’ has incomplete type struct trace_entry ent; \ Change-Id: I26e72db29ec89a305c29a50159279339067f4983 Link: http://lore.kernel.org/r/20190903200905.198642-1-joel@joelfernandes.org Acked-by: Michal Hocko Co-developed-by: Tim Murray Signed-off-by: Tim Murray Signed-off-by: Joel Fernandes (Google) Signed-off-by: Joel Fernandes --- include/linux/mm.h | 14 +++++++++++--- include/trace/events/kmem.h | 21 +++++++++++++++++++++ mm/memory.c | 6 ++++++ 3 files changed, 38 insertions(+), 3 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 2c6130865e5e..39e75cf1dec6 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1646,19 +1646,27 @@ static inline unsigned long get_mm_counter(struct mm_struct *mm, int member) return (unsigned long)val; } +void mm_trace_rss_stat(int member, long count); + static inline void add_mm_counter(struct mm_struct *mm, int member, long value) { - atomic_long_add(value, &mm->rss_stat.count[member]); + long count = atomic_long_add_return(value, &mm->rss_stat.count[member]); + + mm_trace_rss_stat(member, count); } static inline void inc_mm_counter(struct mm_struct *mm, int member) { - atomic_long_inc(&mm->rss_stat.count[member]); + long count = atomic_long_inc_return(&mm->rss_stat.count[member]); + + mm_trace_rss_stat(member, count); } static inline void dec_mm_counter(struct mm_struct *mm, int member) { - atomic_long_dec(&mm->rss_stat.count[member]); + long count = atomic_long_dec_return(&mm->rss_stat.count[member]); + + mm_trace_rss_stat(member, count); } /* Optimized variant when page is already known not to be PageAnon */ diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h index eb57e3037deb..8b88e04fafbf 100644 --- a/include/trace/events/kmem.h +++ b/include/trace/events/kmem.h @@ -315,6 +315,27 @@ TRACE_EVENT(mm_page_alloc_extfrag, __entry->change_ownership) ); +TRACE_EVENT(rss_stat, + + TP_PROTO(int member, + long count), + + TP_ARGS(member, count), + + TP_STRUCT__entry( + __field(int, member) + __field(long, size) + ), + + TP_fast_assign( + __entry->member = member; + __entry->size = (count << PAGE_SHIFT); + ), + + TP_printk("member=%d size=%ldB", + __entry->member, + __entry->size) + ); #endif /* _TRACE_KMEM_H */ /* This part must be outside protection */ diff --git a/mm/memory.c b/mm/memory.c index fb5655b518c9..6491d7a31112 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -70,6 +70,8 @@ #include #include +#include + #include #include #include @@ -138,6 +140,10 @@ static int __init init_zero_pfn(void) } core_initcall(init_zero_pfn); +void mm_trace_rss_stat(int member, long count) +{ + trace_rss_stat(member, count); +} #if defined(SPLIT_RSS_COUNTING)