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Goncalves" , Andrew Morton , Mel Gorman , Thomas Gleixner , John Ogness Subject: Re: [PATCH] mm/page_alloc: Use write_seqlock_irqsave() instead write_seqlock() + local_irq_save(). Message-ID: <20230623104530.vNMEDv9d@linutronix.de> References: <20230621104034.HT6QnNkQ@linutronix.de> <0e9fc992-8e05-2e63-b3b1-d8d3ce89fc16@I-love.SAKURA.ne.jp> <20230621130641.-5iueY1I@linutronix.de> <20230621143421.BgHjJklo@linutronix.de> <20230623081250.h20rlLik@linutronix.de> <20230623095804.Zf03Kn7H@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230623095804.Zf03Kn7H@linutronix.de> X-Stat-Signature: duz1fmondgzjhk3xufwf3cf3gj31teww X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 1CC66160024 X-Rspam-User: X-HE-Tag: 1687517133-819605 X-HE-Meta: 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 sUBrHnH7 XHev832yX9dWZ++507aWT3b6T7MEiDNrHJO4/dpiDXfat18AD/ibqKT1sXizb96yTSGxO2AlEnsDZbkmwZP91YioTTBwG8c0V3abY4qGOOCGhrVD/VK03mHqvA9s4QrokUhdcyXgNZS9K5vw= 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: On 2023-06-23 11:58:05 [+0200], To Michal Hocko wrote: > But first I'm going to use > hotplug-mem to see how it works. I boot qemu with "-m 4G,slots=4,maxmem=16G". | ~# free -h | total used free shared buff/cache available | Mem: 3,8Gi 221Mi 3,6Gi 520Ki 80Mi 3,6Gi | Swap: 0B 0B 0B Telling qemu to add memory: | object_add memory-backend-ram,id=mem1,size=4G | device_add pc-dimm,id=dimm1,memdev=mem1 I see in Linux: | ~# free -h | total used free shared buff/cache available | Mem: 7,8Gi 345Mi 7,5Gi 516Ki 80Mi 7,5Gi | Swap: 0B 0B 0B memory arrived. Nothing in dmesg and my printk in __build_all_zonelists() did not trigger either. Same after I removed memory with: | device_del dimm1 | object_del mem1 it is gone: | ~# free -h | total used free shared buff/cache available | Mem: 3,8Gi 232Mi 3,6Gi 516Ki 80Mi 3,6Gi | Swap: 0B 0B 0B nothing in dmesg. What did I do wrong not to enter __build_all_zonelists()? Sebastian