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c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1746713008; 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=zNZkN1WCALVcw/PVAPOVaDqOYuCC/ZzVpT8rQDEoLlk=; b=U1iwklkQwyXsFTmddVoeBTKhgYw7qy6LmT0gHYe/76gIo4KxkvwpGrESRwGLvVr0weMPzu Rx9fR3S3R6yteYLnxHiS1BMHgGxF7UnlkPgBlSydbZpzTm2MphrXdYMHXpnHt1U22TZWhR wB84+g9yCC1Z5+CFJC/U1mBQ9c8CGyE= Received: by verein.lst.de (Postfix, from userid 2407) id 1CDF067373; Thu, 8 May 2025 16:03:22 +0200 (CEST) Date: Thu, 8 May 2025 16:03:21 +0200 From: Christoph Hellwig To: Matthew Wilcox Cc: Christoph Hellwig , Andrew Morton , Ryusuke Konishi , Hugh Dickins , Johannes Weiner , Yosry Ahmed , Nhat Pham , Chengming Zhou , Baolin Wang , linux-nilfs@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 2/7] mm: stop passing a writeback_control structure to shmem_writeout Message-ID: <20250508140321.GA31543@lst.de> References: <20250508054938.15894-1-hch@lst.de> <20250508054938.15894-3-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-Rspam-User: X-Rspamd-Queue-Id: 08F44180028 X-Rspamd-Server: rspam04 X-Stat-Signature: 3t688ccn3gmjyu4iuji3mg363sq7x5xp X-HE-Tag: 1746713007-92251 X-HE-Meta: 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 eehB7ggt fVmns4ahjNr3R8iydPaJilyni5xYYN07hJ/nx4lAs80Y3Pd3vMZi+NW5TffMdFM+6adsAq7Bnp0MFTdERyNzNRPqCNJMifzll3Uj2kBTsJhDQlfs52tpvaKiqFjVEJphyBs9oFsrObFfJj+fJmXs0PPRfg6Pnyxhh8GSWZFVNTSdwEfctt363QYCaLZxVlvY/exbT2qPrB95LAP/RwX9irU9AeQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, May 08, 2025 at 02:25:00PM +0100, Matthew Wilcox wrote: > This got me to look at why we need to keep wbc in __shmem_writeback(). > We only have it because folio_redirty_for_writepage() needs it. And > folio_redirty_for_writepage() only needs it because it updates > pages_skipped. in linux-next you also changed it to use writeback_iter, which needs the wbc as well. That probably as an improvement compared to the previous version, but overall it still feels odd. > I'm not quite sure if we can simply call filemap_dirty_folio() here > or whether mapping_can_writeback() is true for shmem and we need to > do all the other things -- in which case we could just change that one > line to shmem doesn't set up a bdi, so it should not be true.