+ mm-memcg-add-per-memcg-zswap-writeback-stat.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm: memcg: add per-memcg zswap writeback stat
has been added to the -mm mm-unstable branch.  Its filename is
     mm-memcg-add-per-memcg-zswap-writeback-stat.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memcg-add-per-memcg-zswap-writeback-stat.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Subject: mm: memcg: add per-memcg zswap writeback stat
Date: Tue, 17 Oct 2023 16:21:50 -0700

Since zswap now writes back pages from memcg-specific LRUs, we now need a
new stat to show writebacks count for each memcg.

Link: https://lkml.kernel.org/r/20231017232152.2605440-4-nphamcs@gmail.com
Suggested-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/memcontrol.h |    2 ++
 mm/memcontrol.c            |   15 +++++++++++++++
 mm/zswap.c                 |    3 +++
 3 files changed, 20 insertions(+)

--- a/include/linux/memcontrol.h~mm-memcg-add-per-memcg-zswap-writeback-stat
+++ a/include/linux/memcontrol.h
@@ -38,6 +38,7 @@ enum memcg_stat_item {
 	MEMCG_KMEM,
 	MEMCG_ZSWAP_B,
 	MEMCG_ZSWAPPED,
+	MEMCG_ZSWAP_WB,
 	MEMCG_NR_STAT,
 };
 
@@ -1884,6 +1885,7 @@ static inline void count_objcg_event(str
 bool obj_cgroup_may_zswap(struct obj_cgroup *objcg);
 void obj_cgroup_charge_zswap(struct obj_cgroup *objcg, size_t size);
 void obj_cgroup_uncharge_zswap(struct obj_cgroup *objcg, size_t size);
+void obj_cgroup_report_zswap_wb(struct obj_cgroup *objcg);
 #else
 static inline bool obj_cgroup_may_zswap(struct obj_cgroup *objcg)
 {
--- a/mm/memcontrol.c~mm-memcg-add-per-memcg-zswap-writeback-stat
+++ a/mm/memcontrol.c
@@ -1521,6 +1521,7 @@ static const struct memory_stat memory_s
 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
 	{ "zswap",			MEMCG_ZSWAP_B			},
 	{ "zswapped",			MEMCG_ZSWAPPED			},
+	{ "zswap_wb",			MEMCG_ZSWAP_WB			},
 #endif
 	{ "file_mapped",		NR_FILE_MAPPED			},
 	{ "file_dirty",			NR_FILE_DIRTY			},
@@ -1557,6 +1558,7 @@ static int memcg_page_state_unit(int ite
 	switch (item) {
 	case MEMCG_PERCPU_B:
 	case MEMCG_ZSWAP_B:
+	case MEMCG_ZSWAP_WB:
 	case NR_SLAB_RECLAIMABLE_B:
 	case NR_SLAB_UNRECLAIMABLE_B:
 		return 1;
@@ -7899,6 +7901,19 @@ void obj_cgroup_uncharge_zswap(struct ob
 	rcu_read_unlock();
 }
 
+void obj_cgroup_report_zswap_wb(struct obj_cgroup *objcg)
+{
+	struct mem_cgroup *memcg;
+
+	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
+		return;
+
+	rcu_read_lock();
+	memcg = obj_cgroup_memcg(objcg);
+	mod_memcg_state(memcg, MEMCG_ZSWAP_WB, 1);
+	rcu_read_unlock();
+}
+
 static u64 zswap_current_read(struct cgroup_subsys_state *css,
 			      struct cftype *cft)
 {
--- a/mm/zswap.c~mm-memcg-add-per-memcg-zswap-writeback-stat
+++ a/mm/zswap.c
@@ -704,6 +704,9 @@ static enum lru_status shrink_memcg_cb(s
 	}
 	zswap_written_back_pages++;
 
+	if (entry->objcg)
+		obj_cgroup_report_zswap_wb(entry->objcg);
+
 	/*
 	 * Writeback started successfully, the page now belongs to the
 	 * swapcache. Drop the entry from zswap - unless invalidate already
_

Patches currently in -mm which might be from cerasuolodomenico@gmail.com are

zswap-make-shrinking-memcg-aware.patch
mm-memcg-add-per-memcg-zswap-writeback-stat.patch
selftests-cgroup-update-per-memcg-zswap-writeback-selftest.patch