| From | Neil Brown <> | Date | Tue, 12 Aug 2008 15:35:14 +1000 | Subject | Re: [PATCH 05/30] mm: slb: add knowledge of reserve pages |
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On Thursday July 24, a.p.zijlstra@chello.nl wrote: > Restrict objects from reserve slabs (ALLOC_NO_WATERMARKS) to allocation > contexts that are entitled to it. This is done to ensure reserve pages don't > leak out and get consumed.
This looks good (we are still missing slob though, aren't we :-( )
> @@ -1526,7 +1540,7 @@ load_freelist: > object = c->page->freelist; > if (unlikely(!object)) > goto another_slab; > - if (unlikely(SLABDEBUG && PageSlubDebug(c->page))) > + if (unlikely(PageSlubDebug(c->page) || c->reserve)) > goto debug;
This looks suspiciously like debugging code that you have left in. Is it??
> @@ -265,7 +267,8 @@ struct array_cache { > unsigned int avail; > unsigned int limit; > unsigned int batchcount; > - unsigned int touched; > + unsigned int touched:1, > + reserve:1;
This sort of thing always worries me. It is a per-cpu data structure so you won't get SMP races corrupting fields. But you do get read-modify-write in place of simple updates. I guess it's not a problem.. But it worries me :-)
NeilBrown
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