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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id ABA9BCF884C for ; Thu, 20 Nov 2025 12:24:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 016646B0010; Thu, 20 Nov 2025 07:24:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id F2FFC6B002A; Thu, 20 Nov 2025 07:24:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E45DA6B002C; Thu, 20 Nov 2025 07:24:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id CFA286B0010 for ; Thu, 20 Nov 2025 07:24:51 -0500 (EST) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 833D15B6F6 for ; Thu, 20 Nov 2025 12:24:51 +0000 (UTC) X-FDA: 84130904382.16.35A0B9C Received: from out-181.mta1.migadu.com (out-181.mta1.migadu.com [95.215.58.181]) by imf08.hostedemail.com (Postfix) with ESMTP id 8DA78160009 for ; Thu, 20 Nov 2025 12:24:49 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=tyQRrg2z; spf=pass (imf08.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.181 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1763641489; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=VrpSiTB/zy6tqtQWNYybUDpdeQBD/EoPTcGuovzkLAk=; b=ooe0BTuOHLD7jdoiv8w2Pu10rueVbEDwoDOH7eIWUkLD3fWcLrE2H1JdSrCjONJ3oiO8Iu rLQa/EeUJgdmvXWR7lxCud18Zgh2/JZhb8dQLKyGqs/5gEJ43uBESMsoX++oWkUJB9kDOi Pvn9V1HAVFDWcwv2quXWd4EIczmJYOI= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1763641490; a=rsa-sha256; cv=none; b=JssvtQcexRu3tLLcwW2xi3v18U3GpgqQVqkK6Uomovwk/ZytxG13mVsZaofpXhjX5c2+q8 ev/0UA/wfQYG+50/xKXyEx+1vyT6DTLn4IWOGjdcwf4kmOkpUTLihfG7GqdLjHBQ5CBm2g 3N+B5NjsIyotdec7Mh3sab0aPEAhwks= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=tyQRrg2z; spf=pass (imf08.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.181 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1763641487; h=from:from: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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VrpSiTB/zy6tqtQWNYybUDpdeQBD/EoPTcGuovzkLAk=; b=tyQRrg2zcjxF25xy5X14pftfbqhkRV9KgqB3y6poZGjp7jBlvejZmiwdnhDFkEh0PFyEUB zdAT2EGR9n5UxlBKcW5Xq7ycxyefTn8Vsz1U7CdONNUfLMkJwY8LiNL4JuxahT5sPbS662 W/6wQwaexPBTBRP5Dpik+r7kXm4/O34= Date: Thu, 20 Nov 2025 20:24:19 +0800 MIME-Version: 1.0 Subject: Re: [PATCH V2 2/2] mm/khugepaged: map dirty/writeback pages failures to EAGAIN To: "Garg, Shivank" , Dev Jain Cc: Zi Yan , Baolin Wang , "Liam R . Howlett" , David Hildenbrand , Nico Pache , Ryan Roberts , Barry Song , Andrew Morton , Steven Rostedt , Lorenzo Stoakes , Masami Hiramatsu , Mathieu Desnoyers , Zach O'Keefe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org References: <20251120065043.41738-6-shivankg@amd.com> <20251120065043.41738-10-shivankg@amd.com> <6c1d6b80-d290-4110-9a49-53e7404136bc@arm.com> <33476cb4-318b-49db-9cc1-a354eca9e883@amd.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Lance Yang In-Reply-To: <33476cb4-318b-49db-9cc1-a354eca9e883@amd.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: irpqrq5gqr14a8pst4hb6r4d9fmike4y X-Rspam-User: X-Rspamd-Queue-Id: 8DA78160009 X-Rspamd-Server: rspam01 X-HE-Tag: 1763641489-364515 X-HE-Meta: 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 jgs+WFQy NcN1PJVQkPI2V7XIP4AqGpkM3cWJLoDQap+CJkFJx6QDjblRcJGw7YP4nm4tzjec2R2QRtnsOBmxuwk7jMOlFjWdzSrKsZXlEiEaMU40VTAaarOsg91Tayt9SxTHYrx/YS4+UkdnLRaRMI2So0m3QJ7euruUPL8p50PQWLgZUKw2lWx/qH+ZymCTgFDjM3hWaiBnJ+fiDDLTIcQWBidBdy1mPHPkS5DCyPsd+6mHMe/rveFlNHKDfqmUz679iGfS6t71eLDUcYZWtz7BE1z9IJ27ht/ksifVH+J4+zdePSzyWW7A= 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 2025/11/20 16:17, Garg, Shivank wrote: > > > On 11/20/2025 1:33 PM, Dev Jain wrote: >> >> On 20/11/25 12:20 pm, Shivank Garg wrote: > >> SCAN_PAGE_NOT_CLEAN is confusing - NOT_CLEAN literally means dirty, so why not SCAN_PAGE_DIRTY? >> Or SCAN_PAGE_DIRTY_OR_UNDER_WRITEBACK? Since folio_test_writeback() is true as a result of >> the folio being dirty, maybe just SCAN_PAGE_DIRTY can do. >> >> Reviewed-by: Dev Jain >> > Thanks for the review. > > I chose not to use SCAN_PAGE_DIRTY because dirty and writeback have different meanings[1]: > > Dirty: Memory that is waiting to be written back to disk > Writeback: Memory that is actively being written back to disk > > [1] https://www.kernel.org/doc/Documentation/filesystems/proc.txt > > IIUC, a page under writeback is no longer dirty, so using SCAN_PAGE_DIRTY would be misleading > for pages in the writeback state. > > I considered SCAN_PAGE_DIRTY_OR_WRITEBACK initially but felt it was too long. Nit: If SCAN_PAGE_DIRTY_OR_WRITEBACK is too verbose, how about SCAN_PAGE_DIRTY_WB? It keeps the specificity without the length, and is arguably more descriptive than NOT_CLEAN ;) That said, LGTM. Reviewed-by: Lance Yang > > SCAN_PAGE_NOT_CLEAN covers both states that indicate the page is not in a clean/stable > state suitable for collapse. > > [1] https://www.kernel.org/doc/Documentation/filesystems/proc.txt > > Thanks, > Shivank