From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BF16E338598; Thu, 20 Nov 2025 13:29:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763645370; cv=none; b=PAgrZU8s4Nvrnfsdq26WUV+u1ki2cqmFyfAUDNoGYHCh6juLRDGvSH4Q2BHZTo5sDVKufuIHG+fa8WBGpbKaQFDuXFZRF8N4PS4RO08HmzSUi+ifgSW7HnjdsHA41PxAIXbrhGOg+Cb2DrLanXllmos2oWcUJADZ6rccwK0NyOQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763645370; c=relaxed/simple; bh=WZU8YZVNbH9FupGqUrgw5DmUou46sjiYKi37MvqORC8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=QnbxLhsGpwonv9Zzm6agCWFNAS7afmZuYT91MUPb2f5N+BP1e7WULGBToTZMEWvFPxAKe/69B2otngRJoOMKbYIwcBah7ewbpLmWhjhWl6kRMhjgCrlQFOo7IthG9hiI+rLIbaL8/n7ziaWIzGQ4C6brfuJmXzNj9inqi2aAbZY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dFxAWLwk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dFxAWLwk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 696B2C4CEF1; Thu, 20 Nov 2025 13:29:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763645370; bh=WZU8YZVNbH9FupGqUrgw5DmUou46sjiYKi37MvqORC8=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=dFxAWLwkeJpmG95tU1YvLqrMFtE1xoY8AMaETQkrrGe8tU5jkl/iVac4wQudxnxY1 KhPrO9vx2YTdf90paFpoS7c84BMBaBn8bo979ASlHAC+jJi3qTeKDIj/6mCTvyQwRh ZmfJdYunou9FlkmnekDBfMeM0IoCbbrAF48rrujI5XOjtCoqAWXh+uChbl/DzV9mB6 75Cmv+9JGkDrlMPffuEGxVacn5h7I0NSCpUgI6VqACNET/MkhqZFmInU+Bfrv2g8pL O6DINDJsLkG+Q1kuMCJjKyN83HUHi74xMqfGW9D29Gzv6x5IWaZfnqVJUlPl2I8dYb Vvy4xYKZuM/LA== Message-ID: <81e34d93-9031-4840-a0d0-56d488f3bc17@kernel.org> Date: Thu, 20 Nov 2025 14:29:23 +0100 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V2 2/2] mm/khugepaged: map dirty/writeback pages failures to EAGAIN To: Lance Yang , "Garg, Shivank" , Dev Jain Cc: Zi Yan , Baolin Wang , "Liam R . Howlett" , 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> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 11/20/25 13:24, Lance Yang wrote: > > > 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 I would prefer that here. -- Cheers David