From da6a42c111c874bbc194749c97cc6c0e715e1bcd Mon Sep 17 00:00:00 2001 From: Martin Liu Date: Sat, 8 Mar 2025 03:46:02 +0000 Subject: [PATCH] FROMGIT: mm/page_alloc: add trace event for totalreserve_pages calculation This commit introduces a new trace event, `mm_calculate_totalreserve_pages`, which reports the new reserve value at the exact time when it takes effect. The `totalreserve_pages` value represents the total amount of memory reserved across all zones and nodes in the system. This reserved memory is crucial for ensuring that critical kernel operations have access to sufficient memory, even under memory pressure. By tracing the `totalreserve_pages` value, developers can gain insights that how the total reserved memory changes over time. Link: https://lkml.kernel.org/r/20250308034606.2036033-4-liumartin@google.com Signed-off-by: Martin Liu Acked-by: David Rientjes Cc: "Masami Hiramatsu (Google)" Cc: Mathieu Desnoyers Cc: Steven Rostedt Signed-off-by: Andrew Morton Bug: 396115949 (cherry picked from commit 15766485e4a51bec2dcce304c089a95550720033 https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable) Change-Id: Iced6ea39ad8a36a50bf4393814b6bca2f64ac3b0 Signed-off-by: Martin Liu --- include/trace/events/kmem.h | 18 ++++++++++++++++++ mm/page_alloc.c | 1 + 2 files changed, 19 insertions(+) diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h index 5b1578a4a89e..ed3af0df3692 100644 --- a/include/trace/events/kmem.h +++ b/include/trace/events/kmem.h @@ -402,6 +402,24 @@ TRACE_EVENT(mm_setup_per_zone_lowmem_reserve, __entry->lowmem_reserve) ); +TRACE_EVENT(mm_calculate_totalreserve_pages, + + TP_PROTO(unsigned long totalreserve_pages), + + TP_ARGS(totalreserve_pages), + + TP_STRUCT__entry( + __field(unsigned long, totalreserve_pages) + ), + + TP_fast_assign( + __entry->totalreserve_pages = totalreserve_pages; + ), + + TP_printk("totalreserve_pages=%lu", __entry->totalreserve_pages) +); + + /* * Required for uniquely and securely identifying mm in rss_stat tracepoint. */ diff --git a/mm/page_alloc.c b/mm/page_alloc.c index aecf77d9a672..15087a0d7d71 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8978,6 +8978,7 @@ static void calculate_totalreserve_pages(void) } } totalreserve_pages = reserve_pages; + trace_mm_calculate_totalreserve_pages(totalreserve_pages); } /*