Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) client-ip=23.128.96.37;
From:   Nhat Pham <nphamcs@gmail.com>
To:     akpm@linux-foundation.org
Cc:     hannes@cmpxchg.org, cerasuolodomenico@gmail.com,
        yosryahmed@google.com, sjenning@redhat.com, ddstreet@ieee.org,
        vitaly.wool@konsulko.com, mhocko@kernel.org,
        roman.gushchin@linux.dev, shakeelb@google.com,
        muchun.song@linux.dev, chrisl@kernel.org, linux-mm@kvack.org,
        kernel-team@meta.com, linux-kernel@vger.kernel.org,
        cgroups@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kselftest@vger.kernel.org, shuah@kernel.org
Subject: [PATCH v5 4/6] mm: memcg: add per-memcg zswap writeback stat
Date:   Mon,  6 Nov 2023 10:31:57 -0800
Message-Id: <20231106183159.3562879-5-nphamcs@gmail.com>
In-Reply-To: <20231106183159.3562879-1-nphamcs@gmail.com>
References: <20231106183159.3562879-1-nphamcs@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Domenico Cerasuolo <cerasuolodomenico@gmail.com>

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

Suggested-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
---
 include/linux/vm_event_item.h | 1 +
 mm/memcontrol.c               | 1 +
 mm/vmstat.c                   | 1 +
 mm/zswap.c                    | 3 +++
 4 files changed, 6 insertions(+)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 8abfa1240040..3153359c3841 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -145,6 +145,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 #ifdef CONFIG_ZSWAP
 		ZSWPIN,
 		ZSWPOUT,
+		ZSWP_WB,
 #endif
 #ifdef CONFIG_X86
 		DIRECT_MAP_LEVEL2_SPLIT,
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2ef49b471a16..e43b5aba8efc 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -593,6 +593,7 @@ static const unsigned int memcg_vm_event_stat[] = {
 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
 	ZSWPIN,
 	ZSWPOUT,
+	ZSWP_WB,
 #endif
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 	THP_FAULT_ALLOC,
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 359460deb377..5e5572f3b456 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1401,6 +1401,7 @@ const char * const vmstat_text[] = {
 #ifdef CONFIG_ZSWAP
 	"zswpin",
 	"zswpout",
+	"zswp_wb",
 #endif
 #ifdef CONFIG_X86
 	"direct_map_level2_splits",
diff --git a/mm/zswap.c b/mm/zswap.c
index 2654b0d214cc..03ee41a8b884 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -755,6 +755,9 @@ static enum lru_status shrink_memcg_cb(struct list_head *item, struct list_lru_o
 	}
 	zswap_written_back_pages++;
 
+	if (entry->objcg)
+		count_objcg_event(entry->objcg, ZSWP_WB);
+
 	/*
 	 * Writeback started successfully, the page now belongs to the
 	 * swapcache. Drop the entry from zswap - unless invalidate already
-- 
2.34.1