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bh=GCyPWsTIn/hjYZSAOjujfIp5oyXS1amsxY3tt10sDqI=; b=XAbbVh9s7WzcPUokMUYdRdJo+MHPt6jzHWwvKW09aWviQOrxPSPo0jkcVjqCjHbU3/6U9W RGVIoti6tZSvNztUUaXrD3keDELRBkkv3TgtSVirjBJYnTUn3H6RYsQRZBNiQpP6gDVIxB yHixMQMM6OS+mRnNmV43VOP6Lv1lZsdwCFkkhuXFnsMleZuF1mo0xD0n1mJd+xxiTh1sHS i0hJiQNh788wl7Zi/QVX/lHYgOE5ySqBhcyaWusjWxcHuc2KAd5jeSc50lORyQRxd6Tbia SB5ZzDcnrzg8LTDsYbuib8/fP4uEuu1orgtBF2hHDfog8CSiN/KB0Nt7MF1v4w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1681895270; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=GCyPWsTIn/hjYZSAOjujfIp5oyXS1amsxY3tt10sDqI=; b=QWHQI1ikUQOUFD6XIjUdAxQWGgcOVr+BdtCs6BB8ghxHuEZSIiLuhsjl8DOw7W+A1QDiKm tDmxzKaCBWq4zqCA== To: Petr Mladek , Sergey Senozhatsky , Steven Rostedt Cc: Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Petr Mladek Subject: Re: [PATCH] printk: Enough to disable preemption in printk deferred context In-Reply-To: <20230419074210.17646-1-pmladek@suse.com> References: <20230419074210.17646-1-pmladek@suse.com> Date: Wed, 19 Apr 2023 11:11:52 +0206 Message-ID: <87r0sg5jin.fsf@jogness.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: A88B918000C X-Stat-Signature: gtm1kjk6an5q8n51i46o3zwg1ah191ff X-HE-Tag: 1681895272-751934 X-HE-Meta: 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 jeteEURd f/eEzV1KB0tgzLEM9tWr6ik/x7VllL+bK/6O8bhdjJb6MH/vIHn/9D7YM725m66QihT+3hOewl2LLgJxyQM9lUGMUNqN6MRbvb7JlW6aXm83JRK4RAVHneB9ks53onTd/UpDq 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 2023-04-19, Petr Mladek wrote: > it is safe to interrupt one writer now. The preemption still > has to be disabled because the deferred context is CPU specific. Really it is enough to disable migration. We need to keep an eye on the usage of this function. By allowing interrupts and preemption, it means that other printk's on that CPU will also be deferred if the context interrupted within the deferred block. John