[PATCH v2 3/3] mm: page_counter: drop protection fields from struct page_counter
From: linuszeng via B4 Relay <devnull+linuszeng.tencent.com@kernel.org>
Date: 2026-09-09 09:44:30
Also in:
b4-sent, dri-devel, linux-mm, lkml
Subsystem:
control group - memory resource controller (memcg), the rest · Maintainers:
Johannes Weiner, Michal Hocko, Roman Gushchin, Shakeel Butt, Linus Torvalds
From: linuszeng <redacted> The protection state now lives in struct page_counter_protection, so remove the emin/min_usage/children_min_usage, elow/low_usage/ children_low_usage, min, low and protection_support fields from struct page_counter. Also drop the now-orphaned _pad2_ padding and its comment: with the protection fields gone it no longer separates the read-mostly fields from anything, and the structure's cacheline alignment already pads the tail out. swap/memsw, kmem, tcpmem and hugetlb counters no longer carry this unused state: on 64-bit the structure shrinks from three cache lines to two, saving one cache line. --- include/linux/page_counter.h | 16 ---------------- 1 file changed, 16 deletions(-)
diff --git a/include/linux/page_counter.h b/include/linux/page_counter.h
index b81f16702764..0007960ba5a4 100644
--- a/include/linux/page_counter.h
+++ b/include/linux/page_counter.h@@ -43,27 +43,11 @@ struct page_counter { CACHELINE_PADDING(_pad1_); - /* effective memory.min and memory.min usage tracking */ - unsigned long emin; - atomic_long_t min_usage; - atomic_long_t children_min_usage; - - /* effective memory.low and memory.low usage tracking */ - unsigned long elow; - atomic_long_t low_usage; - atomic_long_t children_low_usage; - unsigned long watermark; /* Latest cg2 reset watermark */ unsigned long local_watermark; - /* Keep all the read most fields in a separete cacheline. */ - CACHELINE_PADDING(_pad2_); - - bool protection_support; bool track_failcnt; - unsigned long min; - unsigned long low; unsigned long high; unsigned long max; struct page_counter *parent;
--
2.43.7