Re: [PATCH] kmsg: Use vmalloc instead of kmalloc when writing

Sasha Levin
2012-03-30T22:03:07Z

On Fri, Mar 30, 2012 at 11:17 PM, Greg KH <gregkh@linuxfoundation.org> wrote:
> On Fri, Mar 30, 2012 at 09:05:52PM +0000, Arnd Bergmann wrote:
>> On Friday 30 March 2012, Thomas Gleixner wrote:
>> > I think so. This is an interface to inject stuff into dmesg. Limiting
>> > that to a reasonable size makes sense. We can probably limit it to
>> > something small like 1024, but I don't know about the "ideas" of those
>> > folks who think that it's a great idea to do it at all.
>>
>> I guess a page would be a reasonable size, similar to what we do for
>> sysfs.
>
> Ok. Sasha, as you seem to have noticed this, care to dig in syslog and
> systemd to get an idea of the buffer sizes they are expecting to pass
> into kmsg, and if they can handle a short write properly?  If so,
> restricting it to a page is fine with me, otherwise we might want to
> make it a bit bigger.

systemd seems to use posix LINE_MAX sized buffers, syslog-ng uses
dynamic strings, but it chews them one line at the time.