linux-kernel - Re: [PATCH] printk: Ratelimit messages printed by console drivers

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Message-ID: <20190228044519.GA32563@jagdpanzerIV>
Date:   Thu, 28 Feb 2019 13:45:19 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
Cc:     Petr Mladek <pmladek@...e.com>,
        Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        akpm@...ux-foundation.org, linux-mm@...ck.org,
        Peter Zijlstra <peterz@...radead.org>, Jan Kara <jack@...e.cz>,
        Tejun Heo <tj@...nel.org>, linux-kernel@...r.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Subject: Re: [PATCH] printk: Ratelimit messages printed by console drivers

On (02/26/19 19:24), Tetsuo Handa wrote:
> Does memory allocation by network stack / driver while trying to emit
> the messages include __GFP_DIRECT_RECLAIM flag (e.g. GFP_KERNEL) ?
> Commit 400e22499dd92613821 handles only memory allocations with
> __GFP_DIRECT_RECLAIM flag. If memory allocation when trying to emit
> the messages does not include __GFP_DIRECT_RECLAIM flag (e.g.
> GFP_ATOMIC / GFP_NOWAIT), doesn't this particular problem still exist?

Console drivers are always called from atomic contexts (including
IRQ->printk->console_driver paths); if any console driver does a
GFP_KERNEL allocation then it should be fixed.

	-ss