From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 F2FFB1DE4FB; Sun, 27 Jul 2025 22:11:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753654275; cv=none; b=ifw6PshWPap4DLlJV4DmkP9V1TWutZ9BcLJ0kQLsrpwbrazaWqbZeb6yeJVoqJMLy47LZFqtbH4X/fWeik9cbsbiwv0lJQTQDUoJZO6Z1xM9lS9ClUOGp7OsqXuUlpLgDyfpRPh2VJywMsAYieGZhM68sampxRySKrzauXrpyOY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753654275; c=relaxed/simple; bh=30hp32qG5yGyWXbTJhUAM3eIIZb3cEDwJ8ZUZKMcD8s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Pc80R223W4dqWFtUAV7Uaz47KF7cHYorsDFJt4ZkYkuEIu4eBFVDQioB0q7zqmLQ+TWVOKMIW5Pmw4iMob8wqvG/8Ymev/a8dZX+ZYF9JDywGRkfRmm6ccRvKaDuMqpNGiF9qwVh9Q4iFB9ZziDKRJ1LjhMZlCyxlLLpzXYy8oc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=dpaUWuT/; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="dpaUWuT/" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=+hW4d7DI3zWYNgpta3mmqm8OPL25IKhqBbArFcbHXd8=; b=dpaUWuT/ujQoHZobKmJKT/dBLC /f0WkM9WTQryrsor7WZ4ag8hTzEgeqc75dnIeiWUHK69AgSdFji9S3Fi8J58qdAPvg1xIlVXFu+k+ 03mohxWGmmuDSCS6y8UWRcqzDji+SIuRPsUEhkhhhxq65fNBXss4CWeP/DLuJj1kYtGbBoEbS/xd5 deW8xhv/13mpcn5BkpVhBO68toOK6+/KDyCJenA+tQWZ5J/+W0JC2lY8z2DeQsm2mSQbE+MTnna3a KdNprXWJM2irc4pux1ngybWKZvsdQyth7Rfk2+TPMAaLZAt/Fcmk+P0fZMjLYOXZ4Yj7BgS9bsy3n Jw3kALjg==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1ug9Zz-00000000Dqj-1nZK; Sun, 27 Jul 2025 22:10:51 +0000 Date: Sun, 27 Jul 2025 23:10:51 +0100 From: Matthew Wilcox To: alexjlzheng@gmail.com Cc: brauner@kernel.org, djwong@kernel.org, dave.hansen@linux.intel.com, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Jinliang Zheng Subject: Re: [PATCH] iomap: move prefaulting out of hot write path Message-ID: References: <20250726090955.647131-2-alexjlzheng@tencent.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250726090955.647131-2-alexjlzheng@tencent.com> On Sat, Jul 26, 2025 at 05:09:56PM +0800, alexjlzheng@gmail.com wrote: > @@ -992,6 +977,12 @@ static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i) > if (mapping_writably_mapped(mapping)) > flush_dcache_folio(folio); > > + /* > + * copy_folio_from_iter_atomic() short-circuits page fault handle > + * logics via pagefault_disable(), to prevent deadlock scenarios > + * when both source and destination buffers reside within the same > + * folio (mmap, ...). > + */ Why did you change this comment from the one in 665575cff098? The comment in that commit is correct. This comment is so badly mangled, it isn't even wrong.