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Goncalves" , Andrew Morton , Mel Gorman , Michal Hocko , Thomas Gleixner Subject: Re: [PATCH] mm/page_alloc: Use write_seqlock_irqsave() instead write_seqlock() + local_irq_save(). Message-ID: <20230621130846.BH0zu3KY@linutronix.de> References: <20230621104034.HT6QnNkQ@linutronix.de> <0e9fc992-8e05-2e63-b3b1-d8d3ce89fc16@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Stat-Signature: jmz9py68fci4t64jf98ye19rxawyktjf X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 8F0BD400B9 X-HE-Tag: 1687352929-788984 X-HE-Meta: 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 DzafiF9S FIBtehYnYKay6Uqq6sCgZXFohy5W9gPzJkSLUK+BEujfQiyMuHKPBfKhXBPLoQSoBdcwAg1ypLB9FCX6gkiTCelnyBjNtO5Hy1y1q2awdRszXXamOUrAuyeLFvM3MOB9XIK0QeO46jOeQCYWSaF+LctC0j/XbJi01Gs15Zl9xEtfRKFtcjZ2bNgdngw/UM9yUDtTwpVaTaQPiKK8bVIJeOajvcVX9e+OxaMojWQazV31B95HM0D14ASQby/+5S0c9IKSJ2vxt+9Aa1xI= 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 2023-06-21 14:40:50 [+0200], Petr Mladek wrote: > I think that we should explicitly disable preemption in > printk_deferred_enter(). The disabled interrupts are not > strictly necessary. > > I am going to resurrect the patch > https://lore.kernel.org/r/20230419074210.17646-1-pmladek@suse.com > and add the preempt_disable()/enable() at the same time. > > Is this going to work for you? No. migrate_disable() is the minimal thing that is needed. However it is heavy weight comparing to what is required. Also by disabling preemption we still have the problem later on with the seqlock_t. Let me swap the lockdep annotation and we should be good. > Best Regards, > Petr Sebastian