Messages in this thread | | | From | Kay Sievers <> | Date | Sat, 31 Mar 2012 02:02:12 +0200 | Subject | Re: [PATCH] kmsg: Use vmalloc instead of kmalloc when writing |
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On Sat, Mar 31, 2012 at 01:43, Greg KH <gregkh@linuxfoundation.org> wrote: > On Sat, Mar 31, 2012 at 12:02:39AM +0200, Sasha Levin wrote: >> 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. > > Ok, care to update this patch with a max size? > > And again, does systemd and syslog-ng handle short writes properly?
Printk has a static scratch buffer of 1024, we can not really process more than that, so we can limit the /dev/kmsg write() to the same size, I guess.
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