From 8c02048d1c6126527f15752a5e0849dc49cefeeb Mon Sep 17 00:00:00 2001 From: Martin Liu Date: Sat, 8 Mar 2025 03:46:00 +0000 Subject: mm/page_alloc: add trace event for per-zone watermark setup Patch series "Add tracepoints for lowmem reserves, watermarks and totalreserve_pages", v2. This patchset introduces tracepoints to track changes in the lowmem reserves, watermarks and totalreserve_pages. This helps to track the exact timing of such changes and understand their relation to reclaim activities. The tracepoints added are: mm_setup_per_zone_lowmem_reserve mm_setup_per_zone_wmarks mm_calculate_totalreserve_pagesi This patch (of 3): This commit introduces the `mm_setup_per_zone_wmarks` trace event, which provides detailed insights into the kernel's per-zone watermark configuration, offering precise timing and the ability to correlate watermark changes with specific kernel events. While `/proc/zoneinfo` provides some information about zone watermarks, this trace event offers: 1. The ability to link watermark changes to specific kernel events and logic. 2. The ability to capture rapid or short-lived changes in watermarks that may be missed by user-space polling 3. Diagnosing unexpected kswapd activity or excessive direct reclaim triggered by rapidly changing watermarks. Link: https://lkml.kernel.org/r/20250308034606.2036033-1-liumartin@google.com Link: https://lkml.kernel.org/r/20250308034606.2036033-2-liumartin@google.com Signed-off-by: Martin Liu Acked-by: David Rientjes Cc: Steven Rostedt Cc: Martin Liu Cc: "Masami Hiramatsu (Google)" Cc: Mathieu Desnoyers Signed-off-by: Andrew Morton --- mm/page_alloc.c | 1 + 1 file changed, 1 insertion(+) (limited to 'mm/page_alloc.c') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2c6ae7e5aaad..b739367434ce 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6006,6 +6006,7 @@ static void __setup_per_zone_wmarks(void) zone->_watermark[WMARK_LOW] = min_wmark_pages(zone) + tmp; zone->_watermark[WMARK_HIGH] = low_wmark_pages(zone) + tmp; zone->_watermark[WMARK_PROMO] = high_wmark_pages(zone) + tmp; + trace_mm_setup_per_zone_wmarks(zone); spin_unlock_irqrestore(&zone->lock, flags); } -- cgit v1.2.3-59-g8ed1b