Messages in this thread | | | Date | Mon, 15 Jun 2009 10:55:47 -0400 (EDT) | From | Christoph Lameter <> | Subject | Re: [GIT PULL v2] Early SLAB fixes for 2.6.31 |
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On Sun, 14 Jun 2009, Pekka J Enberg wrote:
> How about something like this? There should be no extra code in fastpaths > for production configs with this one.
Yes something like that would be good. More comments below.
> index 4d6004c..5e8cea1 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -1613,6 +1613,8 @@ another_slab: > deactivate_slab(s, c); > > new_slab: > + gfpflags &= slab_gfp_mask; > +
Move the processing of GFP_RECLAIM_MASK etc up to here from new_slab? Then the flow is also more logical. The flags handling is concentrated in one spot in the allocator and its more obvious how we handle gfp flags.
> @@ -1668,13 +1670,14 @@ static __always_inline void *slab_alloc(struct kmem_cache *s, > struct kmem_cache_cpu *c; > unsigned long flags; > unsigned int objsize; > + gfp_t real_gfp; > > - gfpflags &= slab_gfp_mask; > + real_gfp = gfpflags & slab_gfp_mask; > > - lockdep_trace_alloc(gfpflags); > - might_sleep_if(gfpflags & __GFP_WAIT); > + lockdep_trace_alloc(real_gfp); > + might_sleep_if(real_gfp & __GFP_WAIT); > > - if (should_failslab(s->objsize, gfpflags)) > + if (should_failslab(s->objsize, real_gfp)) > return NULL; > > local_irq_save(flags);
Dont do it there. Only modify the slow path.
Look at __might_sleep(). It already has an exception for system_state != RUNNING. If it still triggers then add to the condition there.
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