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Wed, 12 Nov 2025 18:11:20 -0800 (PST) Received: from google.com ([2401:fa00:8f:203:2495:f9c3:243d:2a7e]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-bc375eee433sm400380a12.25.2025.11.12.18.11.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Nov 2025 18:11:19 -0800 (PST) Date: Thu, 13 Nov 2025 11:11:14 +0900 From: Sergey Senozhatsky To: Yuwen Chen Cc: axboe@kernel.dk, akpm@linux-foundation.org, bgeffon@google.com, licayy@outlook.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, liumartin@google.com, minchan@kernel.org, richardycc@google.com, senozhatsky@chromium.org Subject: Re: [PATCH v4] zram: Implement multi-page write-back Message-ID: <3vua4ekiwivbeulfirygpll2vhkrtjj7ezafolwyxjuujrcelx@iyx2apjk7oay> References: <83d64478-d53c-441f-b5b4-55b5f1530a03@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 3BB951C0006 X-Stat-Signature: g1ogt5mzj4rs4nc6aqpa1jpfu5iqxfoo X-HE-Tag: 1762999881-754904 X-HE-Meta: U2FsdGVkX1/By9cBr18HzErSA7o7LAuuyLk0vmmjFI4v18sqJ3IzN6t58oTj6GeGl+mATdnaoVAjm4etitUiZWasW9lMvjXRPaj5+vlvF2lBws7raaEWQPsNyKE41YH691QC+VX9u5Wic/e/5nBMpJwwHi9lXwXSwLdAcUFJkmCpQ+DuFXu1yiyX8VNsMI1PNolBbbXVEUHQhK0AXsaJgWPbxYdp8ECo8eb23May2C8wdxWe6lstJNeRKCCByujk9xM3mw5pYyOB7tUTbXoIbAMcBSblXHyHQv32l20JfeBb7zVjtqRPek/2Pj6y59td9JE9DDc49o0meCf/jWRTT0iBETv2LncygUZZk9T5koXLlTgZSLE1Iui+0AUGzA7y8w1QE6YXQHLHsfqoERSI9zF5SHm7NBrkWt7Ewxn7GSz4zI4MrjssH/0FiuzLWTIHtnhOnKdexgN2HuU4YYF3BmBUUQnl+G2BDuYCty7bG1XWPcsOmg105f3w+pcfyey4vNpuxExFwywFbzAhUSWnmYevgIZGUj7RmWSiq/sBnOSBfgKVpmSTLOMxYAfrauu/aQ4k63OGaYn9FnnroZhhFkq8YlVRKjG5VsW+tk0ok1qpAloLtFPLfQ7FoFMrL3wMTkx1py4ryTnfVNdrPC80+9wYX2OwKDF/XCIaT+HQBcx0kNHEan/bpTh/u1EqBAyY/Ck40BBF4trcfNHUKGlVsR+g5vSIyHpKvSQwfbznX1EwTAmzdv8U7jkKlNiW7BY5CjeJTLKbZQR9jPWmkfM7vMmwCYtonfEypQ0Q14qzgs+D837jSH//bq2ntWIkF8xGZ2sIv5Z2qgvYG4GVW4H1mGAY4+o76w2wQhaijGYtD5/W00nSbfgFjL68a8d9SASzCHKYcjOcI93Jh5uCGHE7xwoDBmqpCP/BNi2qsB1HCNxezUuiA7ukCHymh8A/WhdjM6cCBymaBR9yR17OqTK +WD4T8fk I5Xb2tQ1LrLCkV5NXxdEwKIgkRcSsP4zH5IWl42REPP/EiS6zYlN9tngTRLs99xkesT7jpJpR3IrjqqWvPNjXxZdXSTt2snhK9mboyFO3ZACJ3+3VnBw9h7+5MKL+PzxiJ/9w0KFIW3FCdmbatlROXsy+noef+f9KGHtyVyDITTDq6BpPjJbbtSZtXw8BpJg/VKafB1iXab31rJhx+04Yj7BRXg+24wl9kEGbt6+zXaQAHhMGUHBjwXf2loVTfFYusITxQ7AXkON1+ljmibA1svPCnDfCkHsYifoP0yUAh5rFQX37ikupnZ9jPqeFK+llygU7j9eaUBZqSsebukaIx666fcBEWeVj0OBLX/wNkdOX/yM= 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 (25/11/06 09:49), Yuwen Chen wrote: [..] > +static int zram_writeback_slots(struct zram *zram, struct zram_pp_ctl *ctl) > +{ [..] > + struct zram_wb_request req_prealloc[2] = {0}; [..] > + /* allocate memory for req_pool */ > + req_pool = kzalloc(sizeof(*req) * ZRAM_WB_REQ_CNT, GFP_KERNEL); > + if (req_pool) { > + req_pool_cnt = ZRAM_WB_REQ_CNT; > + } else { > + req_pool = req_prealloc; > + req_pool_cnt = ARRAY_SIZE(req_prealloc); > + } This looks like a preliminary optimization, I'd probably prefer to not have req_prealloc entirely.