Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH] printk: inject caller information into the body of
 message
To:     Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Alexander Potapenko <glider@google.com>,
        Dmitriy Vyukov <dvyukov@google.com>,
        kbuild test robot <fengguang.wu@intel.com>,
        syzkaller <syzkaller@googlegroups.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>
References: <CACT4Y+aER3O2x2ApM=MVFoFXhp_T_rUeyG9CBx031qyH0voSRg@mail.gmail.com>
 <20180620130628.GA1000@tigerII.localdomain>
 <CAG_fn=XuZo5yrZzVizP26iV6eFfJtAHUs4NsDFXFyvnaJkdSQw@mail.gmail.com>
 <20180912065307.GA606@jagdpanzerIV>
 <20180912120548.4280f04a@vmware.local.home>
 <20180913071204.GA604@jagdpanzerIV>
 <20180913122625.6ieyexpcmlc5z2it@pathway.suse.cz>
 <20180913142802.GB517@tigerII.localdomain>
 <20180914065728.GA515@jagdpanzerIV>
 <49d22738-17ad-410a-be0a-d27d76ba9f37@i-love.sakura.ne.jp>
 <20180914115028.GB20572@tigerII.localdomain>
From:   Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Message-ID: <e855cbef-03ff-b4ac-3e06-d2f2f48cfb1f@i-love.sakura.ne.jp>
Date:   Fri, 14 Sep 2018 21:03:20 +0900
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:52.0) Gecko/20100101
 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <20180914115028.GB20572@tigerII.localdomain>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 2018/09/14 20:50, Sergey Senozhatsky wrote:
>>> +#define DEFINE_PR_LINE_BUF(lev, name, buf, sz)			\
>>> +	struct pr_line	name = {				\
>>> +		.sb	= __SEQ_BUF_INITIALIZER(buf, (sz)),	\
>>> +		.level	= lev,					\
>>> +	}
>>> +
>>
>> I would use this one for the OOM killer. 80 bytes is too short.
> 
> 80 bytes is quite short for OOM, agreed.
> 
>>   static char oom_print_buf[1024];
>>   DEFINE_PR_LINE_BUF(level, oom_print_buf);
> 
> Do I get it right that you suggest to drop the "size" param?

No. I just forgot to add params. ;-)

> Do OOM people agree on 1024 bytes stack usage?

I won't allocate oom_print_buf on the stack. Since its usage is serialized
by oom_lock mutex, we don't need to allocate from stack. Since memory
allocation request might happen when stack is already tight, we should not
try to allocate much from stack.