lkml.org 
[lkml]   [2008]   [Jun]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: Problem: Out of memory after 2days with 2GB RAM
From
Date

> > Try the patch below. It should improve code generation too.
> >
> > I discussed this with Tomas previously and he says the hw is capable of
> > doing 20 fragments per frame (wonder why, Broadcom can do an unlimited
> > number...) but he complained about the networking stack not being able
> > to.
>
> This is scatter gather buffers that can be kicked in one DMA transaction.
>
> Well, the hardware needs to support IP checksumming for that, hence,
> > afaik, only two fragments can ever be used (one for hw header, one for
> > frame)
> This I still don't understand why but everybody is already tired to
> explaining me why.. :) Just need to find time to dig into it.

And you can safely decrease the allocation to 10% as I do in my patch
because once you understand you'll see that you cannot possibly use
more. Hence, you can ack this patch ;)

> > This cuts the allocation to 10%, or (under) a page in all cases.
>
> Probably. it would be safe to use vmalloc for allocating txb anyway.
> I'll give it a try.

Yeah, but why bother if we can just allocate 10% of the size, waste a
lot less memory etc. mac80211 isn't going to pass in a scatter/gather
frame anyway.

> There was already discussion on LKML about memory allocation problems
> on X86_64, which might explain this regression. This didn't happen
> before.

Doesn't really matter, iwlwifi is _wasting_ this allocation, it cannot
possibly use all those buffers anyway.

The more interesting thing is the pci_alloc_consistent allocation right
below that is also _huge_, but that's because of the stupid hardware
design, or can the hardware cope with having the descriptors non-linear
in memory?

johannes
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2008-06-12 19:07    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site