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X-IronPort-AV: E=McAfee;i="6600,9927,10976"; a="26326492" X-IronPort-AV: E=Sophos;i="6.05,248,1701158400"; d="scan'208";a="26326492" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Feb 2024 17:08:00 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.05,248,1701158400"; d="scan'208";a="32260071" Received: from rmahambr-mobl.amr.corp.intel.com (HELO [10.209.58.248]) ([10.209.58.248]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Feb 2024 17:08:00 -0800 Message-ID: Subject: Re: [PATCH v2] mm: swap: async free swap slot cache entries From: Tim Chen To: Chris Li Cc: "Huang, Ying" , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Wei =?UTF-8?Q?Xu=EF=BF=BC?= , Yu =?UTF-8?Q?Zhao=EF=BF=BC?= , Greg Thelen , Chun-Tse Shao , Suren =?UTF-8?Q?Baghdasaryan=EF=BF=BC?= , Yosry =?UTF-8?Q?Ahmed=EF=BF=BC?= , Brain Geffon , Minchan Kim , Michal Hocko , Mel Gorman , Nhat Pham , Johannes Weiner , Kairui Song , Zhongkun He , Kemeng Shi , Barry Song Date: Tue, 06 Feb 2024 17:08:00 -0800 In-Reply-To: References: <20240131-async-free-v2-1-525f03e07184@kernel.org> <87sf2ceoks.fsf@yhuang6-desk2.ccr.corp.intel.com> <7f19b4d69ff20efe8260a174c7866b4819532b1f.camel@linux.intel.com> <1fa1da19b0b929efec46bd02a6fc358fef1b9c42.camel@linux.intel.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.4 (3.44.4-2.fc36) MIME-Version: 1.0 X-Rspamd-Queue-Id: 6B000A0010 X-Rspam-User: X-Stat-Signature: rpodcgwe9pn6zrytiei3og49jyukr6a4 X-Rspamd-Server: rspam01 X-HE-Tag: 1707268083-654109 X-HE-Meta: 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 ILp6QvPC I1KlC5MBnUPdE7NffZaz9+mpG5xx+DtI7rqxbGw9cBK67CWTf/O7aA0n1jzTXTu51kvS8ed3W4peeyTGm6uEkeRVLV4do4maF8bMddFjCnaVihgQgUBXOqZ0fsf08aderDZHf X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 2024-02-05 at 11:10 -0800, Chris Li wrote: >=20 >=20 > In our system, a really heavy swap load is rare and it means something > is already wrong. At that point the app's SLO is likely at risk, > regardless of long tail swap latency. It is already too late to > address it at the swap fault end. We need to address the source of the > problem which is swapping out too much. >=20 >=20 Could some usage scenarios put more pressure on swap than your usage scenario? Say system with limited RAM and rely on zswap? Tim