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b=Cowy9MsBY3XZQQ1HS6JF8Te3k7jLI7mAAtVWJHKLH7sU5r8T7sHapjoFGr8TgJGdi yWCas/O3bmgijmoco3s2D2Kg/fLcA/crWp4RBM9gmBFBeyxeJn6z+TEQKuU95dr0wH nZXfIF3ABlJnTwV7lSgzMRlWv1z2ekjrnzK39HuA= Date: Thu, 20 Nov 2025 17:17:38 -0800 From: Andrew Morton To: Sergey Senozhatsky Cc: Minchan Kim , Yuwen Chen , Richard Chang , Brian Geffon , Fengyu Lian , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org Subject: Re: [PATCHv4 2/6] zram: add writeback batch size device attr Message-Id: <20251120171738.84516c55e4aaeea0bf3b7725@linux-foundation.org> In-Reply-To: <20251118073000.1928107-3-senozhatsky@chromium.org> References: <20251118073000.1928107-1-senozhatsky@chromium.org> <20251118073000.1928107-3-senozhatsky@chromium.org> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 2EDEBC000C X-Rspamd-Server: rspam07 X-Stat-Signature: as4g4etj1dtiku7j5574mchhnotrw67k X-Rspam-User: X-HE-Tag: 1763687860-954171 X-HE-Meta: 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 C5CXFwxV XWer1phADDNSpyJGHTMAW5RvQt6wRVfjkz4G9PZA54kyfgcLpCsmQCjrUfpNIofW3HcNwJiX9yJQok5kBJx8rk+v49JiFJaEBtdhfnwMe/O10sgkBbJTTH04/ptyjimaPBrzFqS+p0E2uhO1NLs7wnMIKY+CduIXWPujPIi93QJdAeSUUCG4KKCdlUFD2y/lcZBep9OwCRzlk7tvxVJzD0IYcaSmGmOMTtq+E/eftoHE1XVyLYaRyrUap7AfcxZB6tKtVadOLTPMg3KyAXO5rY/Ygww== 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 Tue, 18 Nov 2025 16:29:56 +0900 Sergey Senozhatsky wrote: > Introduce writeback_batch_size device attribute so that > the maximum number of in-flight writeback bio requests > can be configured at run-time per-device. This essentially > enables batched bio writeback. > > ... > > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -588,6 +588,42 @@ static ssize_t writeback_limit_show(struct device *dev, > return sysfs_emit(buf, "%llu\n", val); > } > > +static ssize_t writeback_batch_size_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t len) > +{ > + struct zram *zram = dev_to_zram(dev); > + u32 val; > + ssize_t ret = -EINVAL; > + > + if (kstrtouint(buf, 10, &val)) > + return ret; > + > + if (!val) > + val = 1; > + > + down_read(&zram->init_lock); down_write()? > + zram->wb_batch_size = val; > + up_read(&zram->init_lock); > + ret = len; > + > + return ret; > +}