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 07E4ECD8CA4 for ; Tue, 9 Jun 2026 08:45:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5A0D56B0005; Tue, 9 Jun 2026 04:45:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 551B46B0088; Tue, 9 Jun 2026 04:45:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 467DA6B008A; Tue, 9 Jun 2026 04:45:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 3B4086B0005 for ; Tue, 9 Jun 2026 04:45:17 -0400 (EDT) Received: from smtpin14.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id D73E51C2784 for ; Tue, 9 Jun 2026 08:45:16 +0000 (UTC) X-FDA: 84859739832.14.26A783B Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf16.hostedemail.com (Postfix) with ESMTP id 2145D18000C for ; Tue, 9 Jun 2026 08:45:14 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=lst.de; spf=pass (imf16.hostedemail.com: domain of hch@lst.de designates 213.95.11.211 as permitted sender) smtp.mailfrom=hch@lst.de ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1780994715; 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; bh=Hi/s3Jk0fu83IWGFkY1pD87tmixQ/mAIFgVqk/WtsSI=; b=HlaGrQo1MSKuOhK0rCYGEhbC+MBLhu/ql56eS2SddWikTUiBacYpj6DTkDUrhET31et9X5 7obFNBB52qSZZzFfwQerZUha/DQ26qCxN0qSM28/CqRGwwzJwLkNSteD3JI7r+Yz7ZN6c9 kHAUu1B5yay9Hess2jhFO1Z4ED7j+xI= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=lst.de; spf=pass (imf16.hostedemail.com: domain of hch@lst.de designates 213.95.11.211 as permitted sender) smtp.mailfrom=hch@lst.de ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1780994715; b=Q7oaPnCd6c5k/MLq+/as1istrPnbqCg947L6XGdsiw1Nb7gAcedAWuQr634BNGPbj/Sid5 7QMwX/uwMYzj2c9//s+Hu4PT8fiitFIATKHB+IFj9O9Dp1stWdkY5Pvv1WYlFMVUs5gev4 1vbFTReUWO2up6fS87ircVgCaSRl9BE= Received: by verein.lst.de (Postfix, from userid 2407) id 890DC68B05; Tue, 9 Jun 2026 10:45:11 +0200 (CEST) Date: Tue, 9 Jun 2026 10:45:11 +0200 From: Christoph Hellwig To: Baoquan He Cc: Christoph Hellwig , akpm@linux-foundation.org, chrisl@kernel.org, usama.arif@linux.dev, kasong@tencent.com, nphamcs@gmail.com, shikemeng@huaweicloud.com, youngjun.park@lge.com, linux-mm@kvack.org Subject: Re: [PATCH 7/8] mm/swap: remove SWP_FS_OPS Message-ID: <20260609084511.GB11917@lst.de> References: <20260601113449.3464734-1-hch@lst.de> <20260601113449.3464734-8-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspamd-Queue-Id: 2145D18000C X-Rspam-User: X-Stat-Signature: aqnxpy8whh3bni9nw1hgkfdus8hj1a5n X-Rspamd-Server: rspam09 X-HE-Tag: 1780994714-635913 X-HE-Meta: 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 vzX0LLnk aUIyGvu2QyFi3VTcNLwyqui1xI+ajsbD4aREIIYkD6MEJYcj6dfX3ZQcSk/DCtAx/cR+gPZYjTladKuyQwzYN2Bc25jCPNNqguKCMCRhs0y3W1UvO39ryVWvFUmYI5QzEZsJEKjrboAv8Ms7LQ9b+l7euonXCuuMXLYVW Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Jun 05, 2026 at 01:21:42PM +0800, Baoquan He wrote: > + * SWAP_OPS_F_NOFS: swap operations that may recurse into the filesystem > + * (e.g. NFS, CIFS). When set, callers (specifically reclaim) must operate > + * under GFP_NOFS / !__GFP_FS to avoid deadlock. When clear (block-device > + * swap), the swap I/O path does not touch the filesystem, so reclaim may > + * safely enter the filesystem even with only __GFP_IO. > + * > + * In may_enter_fs() this appears as a double negative (!SWAP_OPS_F_NOFS) > + * which reads as "not a nofs swap => may enter fs". This is intentional: > + * it is bdev swap (the common case) that allows filesystem re-entry, while > + * filesystem-based swap explicitly forbids it. > + */ This is very verbose, but not incorrect. If everyone is fine with it, I can add it to the next version. Or if people think it is clearer. we can add a gfp constraint to the ops?