From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f181.google.com (mail-pl1-f181.google.com [209.85.214.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 566833D093B for ; Mon, 11 May 2026 10:52:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778496746; cv=none; b=F9wI0I4gVarW3iWNWEvkQW3LL3ns9B7EwTFw3nDAwYkV2QaRWsJdxLhK7giHIul3lnMqDTMpYPD/7BxrAQIMMZolm9Hv/NPjCRPqmDPJV5cc73/Q8pO2wG8wxZuiwWAo5G3dPP+OzOBNDkmPXYEIOQaCImglmjQD5raJunkrTRs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778496746; c=relaxed/simple; bh=Leh1MEBHBCTSKNFe7cTJpIBEvX0LcJ1AgIVCFnqVjmE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=FR2mDWE7YSDg9Rr+ZpTGlO0h0iTtUzs51RUxSIK4pneG+BATi1sPQaO8wRo3GY8SqyWA0+JXdkK2m55gCWL4gc5F19xW8bS7cuebbeW2xQTP+F/WOES7eb+5MPwoCatgjeLKw139OnbfIlW0YzXJBLENGRNcUTeX9fYDmtikLWo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Gw796Hjk; arc=none smtp.client-ip=209.85.214.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Gw796Hjk" Received: by mail-pl1-f181.google.com with SMTP id d9443c01a7336-2b9705613ddso25080565ad.1 for ; Mon, 11 May 2026 03:52:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1778496745; x=1779101545; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=n6WtgpEfVE+ktty/21d7K0edFsjegj7CB2gJFywRNtg=; b=Gw796HjkLoA35cR6fFwk8989XD1QCyOm5rl0t6e1HLhIbJSeGfbso0SecXLqqUMeqT tpXGoFDJPpl09luRmkccF6LKJTl/vVJM4yzMzISPOo3V7kn2/O5sEalxReVDshyy53Y8 MwoL2hew/cNeevylvP3hGyCXti8fEXBqOtlVWDnfATRs9oYfelV4GE5qnMWQ8dysDoIG 2m1D2csGZLeuVUuriS9lIOCqfFk2zA9hxRdzDe5EKXITo1pnZXFvDe++tTtRVeCwLLvH H+vRjSddq4z9iClNRs2cFNkJQ1PLmErgjpBx4pmJXFEX4ykVTYgZSzr3YONrGRzgeCr4 k+/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778496745; x=1779101545; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=n6WtgpEfVE+ktty/21d7K0edFsjegj7CB2gJFywRNtg=; b=lf+QysiWIGLDcgOdjSD5xXRMWxpS40nYZLr4ZZrEpOnrIOigi0iIS1G72rcYY5OiY1 OwkMRNPQyjYH/2tR3Pn/juhvfIBOB9thBvACXvP2n7tsJj84QoevJ82qOQDm9d7BR3qP tSgauC1ooX4YBXzYbtQu2oes/nhG5AgJqf4lOfLJW0Tp6t8O1SnYluzjwn+F0pNHeBli AV04EJPyxdxIS/o5lxPtT+2iwvWwjWEjTxHtmw3N17rR2y1JMPwCSV1OYpVgNMII/B1p Gie3gIR0SHFSdCn7LKhXj6zS6LDO9p0qf5CNSM7XI48d6HvXcIYjilPTNeyfgySn2UYe P+CA== X-Forwarded-Encrypted: i=1; AFNElJ86tbjE71lS+FDIN1BU79YpuUbLsPa01o2Spy6aamsLarySbKTMV5kw96ioJxsV3lWn3jE9ObOh4CY=@vger.kernel.org X-Gm-Message-State: AOJu0Yxlm7EQHx03cvsHSoeBLMbe+4YR5MNdYtevHSEsXH1F0/UxpaUg 8FPnEicX94trKEzRZXohBY4kqbq9GNsNQ7gc6+K9wJdlUZMazBFgxSI0 X-Gm-Gg: Acq92OHIx4iuWFN3poGHSWrep8WLCsLqTyMiVkcoZtkVhm6kNT7a30SYnoc8ixf1c9f Crb+hXbJ8ZjKq+62cqJAxh6mLqwqEqPX60sECrpgjfl0vaJwR2/zNrRaH30Up57i4y8nWMqKUW8 3ukt5iZpn7SrunD/DgzN0dHV1iSffCKJq5JF8NIrcVlgkvY2n8f04wNDbDtTa80w65P9QGXRkjL MhjichmImfblXgwSRjUuYa9GsNTjZ6H7eQgvhhbckiT0w0mSJ8RLHc9UpkMmICChfkD+hYC0xI0 /WgFQ3zyp4gDQ1+lF86DImnXR4imJj1rl2+T6yOr6sTIib+AympteUnkt9GlvCIrY6y65/IiBbv IqzijTOWQ0gAezdFt6VpKlEc77z6xB/MtldTISbM/T6tWQYDtKy3ABZepfT+V0mYnD5V24yyC+4 HCjGtyVi4gFN4SLvQX90ixjkHEIHZUlzkXruI8u4B3gQhski6toa5GPHJaRgEOFQ== X-Received: by 2002:a17:902:ee92:b0:2b4:59bf:5728 with SMTP id d9443c01a7336-2ba798c279emr168316355ad.25.1778496744462; Mon, 11 May 2026 03:52:24 -0700 (PDT) Received: from localhost.localdomain ([210.184.73.204]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2baf1d409eesm98571745ad.32.2026.05.11.03.52.18 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Mon, 11 May 2026 03:52:23 -0700 (PDT) From: Hao Jia To: akpm@linux-foundation.org, tj@kernel.org, hannes@cmpxchg.org, shakeel.butt@linux.dev, mhocko@kernel.org, yosry@kernel.org, mkoutny@suse.com, nphamcs@gmail.com, chengming.zhou@linux.dev, muchun.song@linux.dev, roman.gushchin@linux.dev Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Hao Jia Subject: [PATCH 3/3] mm/zswap: Add per-memcg stat for proactive writeback Date: Mon, 11 May 2026 18:51:49 +0800 Message-Id: <20260511105149.75584-4-jiahao.kernel@gmail.com> X-Mailer: git-send-email 2.39.2 (Apple Git-143) In-Reply-To: <20260511105149.75584-1-jiahao.kernel@gmail.com> References: <20260511105149.75584-1-jiahao.kernel@gmail.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Hao Jia Currently, zswap writeback can be triggered by either the pool limit being hit or by the proactive writeback mechanism. However, the existing 'zswpwb' metric in memory.stat and /proc/vmstat counts all written back pages, making it difficult to distinguish between pages written back due to the pool limit and those written back proactively. Add a new statistic 'zswpwb_proactive' to memory.stat and /proc/vmstat. This counter tracks the number of pages written back due to proactive writeback. This allows users to better monitor and tune the proactive writeback mechanism. Signed-off-by: Hao Jia --- Documentation/admin-guide/cgroup-v2.rst | 4 ++++ include/linux/vm_event_item.h | 1 + mm/memcontrol.c | 1 + mm/vmstat.c | 1 + mm/zswap.c | 11 +++++++++-- 5 files changed, 16 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 05b664b3b3e8..29a189b18efc 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1734,6 +1734,10 @@ The following nested keys are defined. zswpwb Number of pages written from zswap to swap. + zswpwb_proactive + Number of pages written from zswap to swap by proactive + writeback. This is a subset of zswpwb. + zswap_incomp Number of incompressible pages currently stored in zswap without compression. These pages could not be compressed to diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h index 03fe95f5a020..7a5bee0a20b6 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -138,6 +138,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, ZSWPIN, ZSWPOUT, ZSWPWB, + ZSWPWB_PROACTIVE, #endif #ifdef CONFIG_X86 DIRECT_MAP_LEVEL2_SPLIT, diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ba7f7b1954a8..830d895e77c3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -572,6 +572,7 @@ static const unsigned int memcg_vm_event_stat[] = { ZSWPIN, ZSWPOUT, ZSWPWB, + ZSWPWB_PROACTIVE, #endif #ifdef CONFIG_TRANSPARENT_HUGEPAGE THP_FAULT_ALLOC, diff --git a/mm/vmstat.c b/mm/vmstat.c index f534972f517d..66fd06d1bb01 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1452,6 +1452,7 @@ const char * const vmstat_text[] = { [I(ZSWPIN)] = "zswpin", [I(ZSWPOUT)] = "zswpout", [I(ZSWPWB)] = "zswpwb", + [I(ZSWPWB_PROACTIVE)] = "zswpwb_proactive", #endif #ifdef CONFIG_X86 [I(DIRECT_MAP_LEVEL2_SPLIT)] = "direct_map_level2_splits", diff --git a/mm/zswap.c b/mm/zswap.c index 1173ac6836fa..bf23c46e838e 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1048,7 +1048,8 @@ static bool zswap_decompress(struct zswap_entry *entry, struct folio *folio) * freed. */ static int zswap_writeback_entry(struct zswap_entry *entry, - swp_entry_t swpentry) + swp_entry_t swpentry, + bool proactive) { struct xarray *tree; pgoff_t offset = swp_offset(swpentry); @@ -1108,6 +1109,12 @@ static int zswap_writeback_entry(struct zswap_entry *entry, if (entry->objcg) count_objcg_events(entry->objcg, ZSWPWB, 1); + if (proactive) { + count_vm_event(ZSWPWB_PROACTIVE); + if (entry->objcg) + count_objcg_events(entry->objcg, ZSWPWB_PROACTIVE, 1); + } + zswap_entry_free(entry); /* folio is up to date */ @@ -1223,7 +1230,7 @@ static enum lru_status shrink_memcg_cb(struct list_head *item, struct list_lru_o */ spin_unlock(&l->lock); - writeback_result = zswap_writeback_entry(entry, swpentry); + writeback_result = zswap_writeback_entry(entry, swpentry, proactive_wb); if (writeback_result) { zswap_reject_reclaim_fail++; -- 2.34.1