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Wed, 08 Apr 2026 12:36:47 -0700 (PDT) X-Received: by 2002:a05:622a:1a86:b0:50d:6b6d:bc17 with SMTP id d75a77b69052e-50dc212b2e3mr10298851cf.23.1775677007355; Wed, 08 Apr 2026 12:36:47 -0700 (PDT) Received: from [192.168.129.206] ([216.158.158.246]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-50d64752857sm142454931cf.21.2026.04.08.12.36.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 08 Apr 2026 12:36:46 -0700 (PDT) Message-ID: Date: Wed, 8 Apr 2026 15:36:45 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v4 2/3] iomap: use BIO_COMPLETE_IN_TASK for dropbehind writeback To: Matthew Wilcox Cc: Jens Axboe , Christian Brauner , "Darrick J. Wong" , Carlos Maiolino , Alexander Viro , Jan Kara , Christoph Hellwig , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org References: <20260325-blk-dontcache-v4-0-c4b56db43f64@columbia.edu> <20260325-blk-dontcache-v4-2-c4b56db43f64@columbia.edu> Content-Language: en-US From: Tal Zussman In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Proofpoint-GUID: 6EvSO2ZD-tzjND6sYAJk7mt0N5sBfEv0 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNDA4MDE4MyBTYWx0ZWRfX7sLdAzx8ctZC jo+5GIgy3AVocaU2CQ/KZLb8a4xAk0zPXMe4WIqX69J4En4VJNsDtvq/j5G5lOWR5PE905GmtOv /Hpwfnosj8pUpX9DFxhm6d4CaPzcEe5x+eLtJ08X3Urd7+UeQgUlGPLMeTGX7LlmLAbhm4l+r6l 01+sxHk12ImNk1ikv6lxQXA9Wi6mAVoKWf2B/Wxw/gDGBQ1aKB0Do7iRmMeXOFPKD0zoU9YMkQQ /s7c3vzyT/OZqdv156+h8eJgMv/hz58uaE/Soaxj5jaZND+Q0Iecjum4/N0E3IqDmXw08iBZ6VV A8iHKxqCR6P1OlpdagYPAle3dq0KiIMmbahg005OhpGtJhVDbcswpbJC/hfLqeWkLtdLtWgmo0A CK5KVesD+vfqF7AaLXM1qKizSO77DrIqJOoQDMDnzV2zkvqfb1bX84vn51LFJBiqkbJ0+kEPsp0 ejgq6kXdCrnCyyF7xDg== X-Authority-Analysis: v=2.4 cv=QPRYgALL c=1 sm=1 tr=0 ts=69d6ae50 cx=c_pps a=WeENfcodrlLV9YRTxbY/uA==:117 a=mD05b5UW6KhLIDvowZ5dSQ==:17 a=IkcTkHD0fZMA:10 a=A5OVakUREuEA:10 a=x7bEGLp0ZPQA:10 a=VkNPw1HP01LnGYTKEx00:22 a=Da8U98TiO7q1upZEImrf:22 a=79PYxaXUQd1wl-QFWJnA:22 a=fDzNMwFgse8Xf2NrkjQA:9 a=QEXdDO2ut3YA:10 a=kacYvNCVWA4VmyqE58fU:22 X-Proofpoint-ORIG-GUID: 6EvSO2ZD-tzjND6sYAJk7mt0N5sBfEv0 X-Proofpoint-Virus-Version: vendor=nai engine=6800 definitions=11753 signatures=596818 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 suspectscore=0 bulkscore=10 malwarescore=0 phishscore=0 priorityscore=1501 clxscore=1015 spamscore=0 impostorscore=10 lowpriorityscore=10 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604010000 definitions=main-2604080183 On 3/25/26 4:21 PM, Matthew Wilcox wrote: > On Wed, Mar 25, 2026 at 02:43:01PM -0400, Tal Zussman wrote: >> Set BIO_COMPLETE_IN_TASK on iomap writeback bios when >> IOMAP_IOEND_DONTCACHE is set. This ensures that bi_end_io runs in task >> context, where folio_end_dropbehind() can safely invalidate folios. >> >> With the bio layer now handling task-context deferral generically, XFS >> no longer needs to route DONTCACHE ioends through its completion >> workqueue for page cache invalidation. Remove the DONTCACHE check from >> xfs_ioend_needs_wq_completion(). >> >> Signed-off-by: Tal Zussman >> --- >> fs/iomap/ioend.c | 2 ++ >> fs/xfs/xfs_aops.c | 4 ---- >> 2 files changed, 2 insertions(+), 4 deletions(-) >> >> diff --git a/fs/iomap/ioend.c b/fs/iomap/ioend.c >> index e4d57cb969f1..6b8375d11cc0 100644 >> --- a/fs/iomap/ioend.c >> +++ b/fs/iomap/ioend.c >> @@ -113,6 +113,8 @@ static struct iomap_ioend *iomap_alloc_ioend(struct iomap_writepage_ctx *wpc, >> GFP_NOFS, &iomap_ioend_bioset); >> bio->bi_iter.bi_sector = iomap_sector(&wpc->iomap, pos); >> bio->bi_write_hint = wpc->inode->i_write_hint; >> + if (ioend_flags & IOMAP_IOEND_DONTCACHE) >> + bio_set_flag(bio, BIO_COMPLETE_IN_TASK); >> wbc_init_bio(wpc->wbc, bio); >> wpc->nr_folios = 0; >> return iomap_init_ioend(wpc->inode, bio, pos, ioend_flags); > > Can't we delete IOMAP_IOEND_DONTCACHE, and just do: > > if (folio_test_dropbehind(folio)) > bio_set_flag(&ioend->io_bio, BIO_COMPLETE_IN_TASK); > > It'd need to move down a few lines in iomap_add_to_ioend() to after > bio_add_folio() succeeds. > Will do, thanks Matthew!