From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB263C28B28 for ; Wed, 12 Mar 2025 18:12:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B64B3280003; Wed, 12 Mar 2025 14:11:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AED0A280001; Wed, 12 Mar 2025 14:11:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 98EF7280003; Wed, 12 Mar 2025 14:11:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 7CAB5280001 for ; Wed, 12 Mar 2025 14:11:57 -0400 (EDT) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 7CA2F16146C for ; Wed, 12 Mar 2025 18:11:59 +0000 (UTC) X-FDA: 83213692758.25.029AAA9 Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by imf28.hostedemail.com (Postfix) with ESMTP id AEF96C0010 for ; Wed, 12 Mar 2025 18:11:57 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=W0pP4BPu; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf28.hostedemail.com: domain of minchan@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=minchan@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1741803117; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=+dlg+EIthqGXo7XZLbSA1qhX/dBzGVxPFuPapX5hqVE=; b=6/9E28E1bfYs9a/HYO/QaIVM6CTmEuk6WY9azVCeoAAj0CTiYaDM7EyLYks1ekS8WMwOwu qKKZz4BgJPlJ9FXscaPZ4Nu01O2HjV1VSXwnjf5lu20esnSxeIHXRfFITq+gjMubrW8u/b KZtDAdMtFXTFnc3dO9CUCkOY8nBs6P0= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1741803117; a=rsa-sha256; cv=none; b=FEX03PgbHylUZuGHsz73h+uv1rBWjK6TngrkzPJWzRmcOqhuZyupWqQEJdaQjeZVtyf09k qX+r7Ivs4jQ/fQAQYNSuYVQNwPUzS/KLeFZIk8UWWpfq9sinJulcCEAN/BK2e50eLh72GF EVRYxMnaawh9Vt579p0u9dIPQOmrBys= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=W0pP4BPu; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf28.hostedemail.com: domain of minchan@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=minchan@kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id C77D8A47115; Wed, 12 Mar 2025 18:06:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4192C4CEEA; Wed, 12 Mar 2025 18:11:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741803116; bh=cV5aSqFJ33K30QuBwrJdyen4GmLJdTHeksSaAnwrNvk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=W0pP4BPua5VsTBkh0FpSVUqjdFqimB1E+VhzMfKj3ctZXHRbRoSqGEi2sXcYjAHkM AghgELe61AVdvO6cTJzCyvvnuYRi9FreuYv0GjGr2oYuKJVm7MWfVPuHHtqn40iGRI IErzgBV9Kmr6i6sTf90ZySBfDMiH/bQYM9r5ZlrkZw5YjXZ7hfUhD+bDu9izHJmgJ5 oDzftJeZQckOAzX/RDfLlhNnH5zknbTIl++WmF+AmRWd6FwaC4UKbe8I4XddiJ6vzx Gv72okJGBz5sy9Xen7AHpUVXS84F/DtQxccnT+nnBBIsv2gxNPmEF8Nl/iyJ7JF6uV 1vr8/HHt4tnlg== Date: Wed, 12 Mar 2025 11:11:54 -0700 From: Minchan Kim To: Qun-Wei Lin Cc: Jens Axboe , Sergey Senozhatsky , Vishal Verma , Dan Williams , Dave Jiang , Ira Weiny , Andrew Morton , Matthias Brugger , AngeloGioacchino Del Regno , Chris Li , Ryan Roberts , "Huang, Ying" , Kairui Song , Dan Schatzberg , Barry Song , Al Viro , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, nvdimm@lists.linux.dev, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Casper Li , Chinwen Chang , Andrew Yang , James Hsu Subject: Re: [PATCH 0/2] Improve Zram by separating compression context from kswapd Message-ID: References: <20250307120141.1566673-1-qun-wei.lin@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250307120141.1566673-1-qun-wei.lin@mediatek.com> X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: AEF96C0010 X-Stat-Signature: 3ptcimqrbgbgz8faj1x79kbyui397deq X-HE-Tag: 1741803117-151933 X-HE-Meta: U2FsdGVkX1/xjRu0HpYAHCvm28P/jAeooYQaZrLHj9tFF3U7WIkZ04oy4oP/wfy8HWFNeJTceDUavZPbuBS5+o4qSA+1V4CYdNjj85UGpYejEPpcA/dBC5Oywzt7bEvdYjKu/Mam+2h8Td15A1vItFbytlaGJOu8JXUWrPabL0dCmkbpbcUDcT8yVolIbSd2BEDQm0Ts3YgbtFcnMc494Eho5wJwgWftYFNkZK/dT/OuS2d8/+GoxDEdzAbqYlacGMHE7QQgdB36Mj4CcRa35aZ+aup8lB+zuF5RYDyvsjeM6kRSyJDH0k411PlnendEG++51NV9k3qCpo3hog6ZUwwP/Qzg9eslWMk5H3+Mou4K/Q0hfdMTnWhySJ2kEa7NL97xvcQLmz4gUXnDHs5w43TD/jQheBqkMAbiKmpXN03/Jbo7T6wCxJqPoaTs5hLKDD+Fc26xZvZlPLnNpkXPcu7x387xsGVidlQAIvXhqjBsDfpnaocpQtL/w0xgZpFlXZxFtIn/rcgYgEMLHvx3sJzhbwuOs8l4/bPcCKVirAlKKZkU4N92hhfADC+gODikcZ94P++ysvR7WKMdRuib+0iC9bB3Rqj0L9y88o/Fldod5TAPlve3aa9jEvi9MjrYtxQLkCbFH6HP7eeDfNG8XYl72gzQLeOfDc2v4YtaLbkHpcjpWDExjzjLhWbBfN17tB2vM8YtAHSQDefCY8fzlcQpz7MHWUsd46YqoDbc44u41XOgIM3sM/yW1Ys+pUksF42InYRGVKRRKAJeAa/SGb77AAJM5Ayv462FrqdquAUJAjtYKKu2zkSmmNPcyNRi2KfTIbdUdhy9/6s1Jh6NQEoe6UG9+FZJB3Fi1xxKVsKSmCa5IaJxUXX3FrOXmBg+jxUsQpmbDNPnsm02esF2nvnEisyJbQ8VaiT3A8q/ZnJQkLSpje2RvEtddQQmf4NWUU8xWOiJ8kqLOIdRRAj 4QV4kBJp emkweUF/dmWhQCrKQvgYcQFQvyN+eRwqJ9kVjN54zg0RmwtWjHpC0v5O6qrr6EgKiAQHGlmkss8Nb2A8e2/KqRImoSbTcfLa4R7jTytmviSH8dRisUcyLlAARg8fm5nqkdxG9Uow1lZI6pnEa8Y36iskxOYuJ0qSjy1VChVRr6DJB5Jskkc6DnNsdjEOBeABJc8PHHbW6NU1blN3u/QKSr/egHXVXIR2LRUcFK/QAE9yyR6uwgYwd4GD8v2DxDvMc7hBonWd/l6BX0uMBO/RKtk26Q74se068ZXT5/kJLAvMqriQyLkIYjqT9GXSAhmUBhXPFDiLLfJzudmCGqU0UXTnffpABobyFTE0Qd1658Ew8Fr8= 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: Hi Qun-Wei On Fri, Mar 07, 2025 at 08:01:02PM +0800, Qun-Wei Lin wrote: > This patch series introduces a new mechanism called kcompressd to > improve the efficiency of memory reclaiming in the operating system. The > main goal is to separate the tasks of page scanning and page compression > into distinct processes or threads, thereby reducing the load on the > kswapd thread and enhancing overall system performance under high memory > pressure conditions. > > Problem: > In the current system, the kswapd thread is responsible for both > scanning the LRU pages and compressing pages into the ZRAM. This > combined responsibility can lead to significant performance bottlenecks, > especially under high memory pressure. The kswapd thread becomes a > single point of contention, causing delays in memory reclaiming and > overall system performance degradation. Isn't it general problem if backend for swap is slow(but synchronous)? I think zram need to support asynchrnous IO(can do introduce multiple threads to compress batched pages) and doesn't declare it's synchrnous device for the case.