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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: <20230623095804.Zf03Kn7H@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> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 4637A1C0020 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: fgjers96dqbyf9ek419ia5p9s68mhzpb X-HE-Tag: 1687514286-555455 X-HE-Meta: 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 x+Kn5kMP YFx4t5CvvGN3FNFKkgafe8EMDQi7iOthDO1YgG0QAf+0aC5AiDVl2ei6fc29FncgbSJBDomKb3jrc6fFzmkIiCViZIzO3RfalzJur5x9Z/2vHwzmhjE1jMca77ohrtGRgKpF38OLHnLqAsd8IJUwKIly+et7h19ua6u+P866IOdNwU3U= 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 11:21:01 [+0200], Michal Hocko wrote: > On Fri 23-06-23 10:12:50, Sebastian Andrzej Siewior wrote: > [...] > > It would do _but_ is it really needed? All users but one (the one in > > __build_all_zonelists()) have interrupts already disabled. This isn't a > > hot path and is not used very common. Does it justify the ifdef? > > This is not my call of course but let me just stress out that if all > that is just because of __build_all_zonelists then it is likely not > really worth it. We are talking about memory hoptlug here. I seriously > doubt that this is something anybody would be using with RT > expectations. My current plan to repost this with a better explanation and with printk deferred within the locked region. But first I'm going to use hotplug-mem to see how it works. If it can be enabled on RT then it should work even if nobody is using it. Is someone objecting and if so why. Sebastian