lkml.org 
[lkml]   [2007]   [Feb]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [linux-usb-devel] 2.6.20 kernel hang with USB drive and vfat doing ftruncate
On Wed, 21 Feb 2007, Andrew Morton wrote:

> On Wed, 21 Feb 2007 16:22:17 -0500 (EST)
> Alan Stern <stern@rowland.harvard.edu> wrote:
>
> > On Wed, 21 Feb 2007, Andrew Morton wrote:
> >
> > > > > It seems like usb-storage and aio are completely off in the weeds.
> > > > > Ideas?
> > > >
> > > > It seems usb-storage should remove some kmalloc and use mempool() for
> > > > urb... Is someone working on this? And idea?
> > >
> > > I think Pete said that we're supposed to be using GFP_NOIO in there.
> >
> > We _are_ using it.
>
> How admirably prompt.

Shucks, we've been using it for years...

> > > Not that it'll help much: the VM calls throttle_vm_writeout() for GFP_NOIO
> > > and GFP_NOFS allocations, which is a bug. Because if the caller holds
> > > locks which prevent filesystem or IO progress, we deadlock.
> > >
> > > I'll fix the VM if someone else fixes USB ;)
> >
> > What else needs to be fixed?
>
> Would be nice if someone can confirm that this fixes it:

Not having experienced the problem, I can't confirm the fix. However...

> + if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO)) {

Is that really the correct test? I don't know enough about the memory
management subsystem to say one way or the other. What's special about
having both flags set?

> + /*
> + * The caller might hold locks which can prevert IO completion
--------------------------------------------------------------^ Typo

Although perhaps "prevert" is an acceptable neologism in this context.

> + * or progress in the filesystem. So we cannot just sit here
> + * waiting for IO to complete.
> + */

Alan Stern

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-02-21 22:53    [W:0.129 / U:3.204 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site