Messages in this thread | | | Date | Tue, 16 Dec 2008 08:42:12 +0900 | From | "MinChan Kim" <> | Subject | Re: [rfc][patch] SLQB slab allocator |
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Hi, Nick. I am interested in SLQB. So I tested slqb, slub, slab by kernel compile time.
make all -j 8
slqb and slub not DEBUG. my test environment is as follows.
cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz stepping : 11 cpu MHz : 1600.000 cache size : 4096 KB
Below is average for ten time test.
slab : user : 2376.484, system : 192.616 elapsed : 12:22.0 slub : user : 2378.439, system : 194.989 elapsed : 12:22.4 slqb : user : 2380.556, system : 194.801 elapsed : 12:23.0
so, slqb is rather slow although it is a big difference. Interestingly, slqb consumes less time than slub in system.
And I found some trivial bug. :)
<snip>
> +static struct slqb_page *new_slab_page(struct kmem_cache *s, gfp_t flags, int node) > +{ > + struct slqb_page *page; > + void *start; > + void *last; > + void *p; > + > + BUG_ON(flags & GFP_SLAB_BUG_MASK); > + > + page = allocate_slab(s, > + flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node); > + if (!page) > + goto out; > + > + page->flags |= 1 << PG_slab;
PG_slab set is redundant. It's already set in alloc_slqb_pags_node.
> + start = page_address(&page->page); > + > + if (unlikely(slab_poison(s))) > + memset(start, POISON_INUSE, PAGE_SIZE << s->order);
<snip>
> +void kfree(const void *object) > +{ > + struct kmem_cache *s; > + struct page *p; > + struct slqb_page *page; > + unsigned long flags; > + > + if (unlikely(ZERO_OR_NULL_PTR(object))) > + return; > + > + p = virt_to_page(object); > + prefetch(p); > + prefetchw(object); > + > +#ifdef CONFIG_SLQB_DEBUG > + page = (struct slqb_page *)compound_head(p); > + s = page->list->cache; > + debug_check_no_locks_freed(object, s->objsize); > + if (likely(object) && unlikely(slab_debug(s))) { > + if (unlikely(!free_debug_processing(s, object, __builtin_return_address(0)))) > + return; > + } > +#endif > + > + local_irq_save(flags); > +#ifndef CONFIG_SLQB_DEBUG > + page = (struct slqb_page *)compound_head(p); > + s = page->list->cache; > +#endif
If it is not defined CONFIG_SLQB_DEBUG, page is garbage.
> + __slab_free(s, page, object); > + local_irq_restore(flags); > +} > +EXPORT_SYMBOL(kfree); > +
-- Kinds regards, MinChan Kim
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