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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Mike Snitzer , Jens Axboe , Chuck Lever , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 1/3] mm: kick writeback flusher instead of inline flush for IOCB_DONTCACHE Message-ID: References: <20260408-dontcache-v2-0-948dec1e756b@kernel.org> <20260408-dontcache-v2-1-948dec1e756b@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspamd-Queue-Id: 63C6F18000A X-Stat-Signature: xyehrcqicfkj7wnh4ueruw1qubi9yatg X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1775744504-645016 X-HE-Meta: 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 fp3+To01 Kbk0dshOib3j8op8e3q94c6sxepMAV5RnEDnm/K6lPbnm5VghC24aszHSsb4/8zunAfn5JILDnmwbUS1tc0Vj8yNXVc+AI7aQm78XWn1FWkXGThmFHT9y1/SlG6rh2erI3CW483uKk158YnBEvX/H/SDRK4N1g7/HUxMUZOGm/2ALKaxVZLC1H7mFErYxQOtipI7Ih+VDONkmwl/eD58aXORvTK4yTbQErOkudr6Fs5pW3mlfeNK9lt92sCg1N5L89dLCl50aYeDY77snIxxfVZTO+UvLIxiwiaJyTE7CR2iPTb76Og6BOrt+mdyRb5KDNWYd52xtmflJu7lu/ByOndwMJ0t2vPJn3+DgJqUqSO+W2eNkHXb6Sv4CKt0Akhw/8iVSquD93soAH1JsiOz0aricpx+iwdZ1XgR9L+MRyZsb/kPlA9q/sXU3DjYUeOieWsPDH4xiCKtIZPRHTAJ4Zybq8UxteJ/4ulGyyfHRu6WTeQrc6c9qUgYpR/4n+fC97g5uq7ZJiKu2YVaf9xbDJrmprjUK4blqzpyS5I07EuwB0o8= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Apr 09, 2026 at 09:21:36AM +0200, Jan Kara wrote: > > So I think you'll want a new WB_start_dontcache bit, a new > > get_nr_dontcache_pages() helper on a new node counter, etc. > > But I'm not sure how you imagine this would work without restricting > writeback to particular inodes. Maybe we could mark inodes which have > folios with dropbehind set and make flush worker only write such inodes? I'd only expedite writing by the number of pending dontcache folios. It would still write the least recently dirtied inodes.