lkml.org 
[lkml]   [2014]   [Jun]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 5/9] perf/x86: implement cross-HT corruption bug workaround
On Thu, Jun 05, 2014 at 04:11:50PM +0200, Peter Zijlstra wrote:
> > > x86_schedule_event()
> > > ->start_scheduling()
> > > spin_lock()
> > > ->get_event_constraints()
> > > intel_get_excl_constraints()
> > > kmalloc(.gfp=GFP_KERNEL)
> > >
> > > How can that ever work?
>
> > Are you saying it is illegal to call kmalloc() from
> > this context?
>
> Nobody will come and arrest you for it, so no. Broken though. GFP_KERNEL
> will attempt to sleep to wait for reclaim, and you're holding a
> spinlock.

Furthermore, even GFP_ATOMIC shouldn't be used because these are/should
be raw_spinlocks and the zone->lock is a regular spinlock.

So please look into the preallocation thing.
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2014-06-05 17:41    [W:0.071 / U:0.160 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site