From 77dfeaa02dc3cea434aa19cf70537e0d3d3d9b8b Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Tue, 10 Dec 2019 10:45:34 -0500 Subject: [PATCH] ANDROID: mm: Throttle rss_stat tracepoint Previously we were throttling rss_stat tracepoint by checking for 512KB boundary cross over. We removed that because upstream suggested eBPF or other ways. However right now, we don't have support for those. Let us re introduce the patch to throttle and avoid large number of events which are causing data loss. Bug: 145972256 Change-Id: I4132133aa36163430069b3ca2f57443940fb90b3 Signed-off-by: Joel Fernandes (cherry picked from commit b3ddf584b0d6042bb355969ec0f3fa6a2a6117f6) --- include/linux/mm.h | 9 +++++---- mm/memory.c | 16 ++++++++++++++-- 2 files changed, 19 insertions(+), 6 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 8b3660e82890..aed84145c1b1 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1628,27 +1628,28 @@ static inline unsigned long get_mm_counter(struct mm_struct *mm, int member) return (unsigned long)val; } -void mm_trace_rss_stat(struct mm_struct *mm, int member, long count); +void mm_trace_rss_stat(struct mm_struct *mm, int member, long count, + long value); static inline void add_mm_counter(struct mm_struct *mm, int member, long value) { long count = atomic_long_add_return(value, &mm->rss_stat.count[member]); - mm_trace_rss_stat(mm, member, count); + mm_trace_rss_stat(mm, member, count, value); } static inline void inc_mm_counter(struct mm_struct *mm, int member) { long count = atomic_long_inc_return(&mm->rss_stat.count[member]); - mm_trace_rss_stat(mm, member, count); + mm_trace_rss_stat(mm, member, count, 1); } static inline void dec_mm_counter(struct mm_struct *mm, int member) { long count = atomic_long_dec_return(&mm->rss_stat.count[member]); - mm_trace_rss_stat(mm, member, count); + mm_trace_rss_stat(mm, member, count, -1); } /* Optimized variant when page is already known not to be PageAnon */ diff --git a/mm/memory.c b/mm/memory.c index ece007d30a00..542f0d8af661 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -154,9 +154,21 @@ static int __init init_zero_pfn(void) } core_initcall(init_zero_pfn); -void mm_trace_rss_stat(struct mm_struct *mm, int member, long count) +/* + * Only trace rss_stat when there is a 512kb cross over. + * Smaller changes may be lost unless every small change is + * crossing into or returning to a 512kb boundary. + */ +#define TRACE_MM_COUNTER_THRESHOLD 128 + +void mm_trace_rss_stat(struct mm_struct *mm, int member, long count, + long value) { - trace_rss_stat(mm, member, count); + long thresh_mask = ~(TRACE_MM_COUNTER_THRESHOLD - 1); + + /* Threshold roll-over, trace it */ + if ((count & thresh_mask) != ((count - value) & thresh_mask)) + trace_rss_stat(mm, member, count); } EXPORT_SYMBOL_GPL(mm_trace_rss_stat);