From 15766485e4a51bec2dcce304c089a95550720033 Mon Sep 17 00:00:00 2001 From: Martin Liu Date: Sat, 8 Mar 2025 03:46:02 +0000 Subject: [PATCH] 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 --- 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 9623e68d4d267..f74925a6cf694 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 a82d96cb30440..0be1fedd12012 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5914,6 +5914,7 @@ static void calculate_totalreserve_pages(void) } } totalreserve_pages = reserve_pages; + trace_mm_calculate_totalreserve_pages(totalreserve_pages); } /* -- 2.50.1