Messages in this thread | | | Date | Tue, 16 Dec 2014 11:54:12 +0400 | Subject | Re: [PATCH 3/7] slub: Do not use c->page on free | From | Andrey Ryabinin <> |
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2014-12-16 5:42 GMT+03:00 Joonsoo Kim <iamjoonsoo.kim@lge.com>: > On Mon, Dec 15, 2014 at 08:16:00AM -0600, Christoph Lameter wrote: >> On Mon, 15 Dec 2014, Joonsoo Kim wrote: >> >> > > +static bool same_slab_page(struct kmem_cache *s, struct page *page, void *p) >> > > +{ >> > > + long d = p - page->address; >> > > + >> > > + return d > 0 && d < (1 << MAX_ORDER) && d < (compound_order(page) << PAGE_SHIFT); >> > > +} >> > > + >> > >> > Somtimes, compound_order() induces one more cacheline access, because >> > compound_order() access second struct page in order to get order. Is there >> > any way to remove this? >> >> I already have code there to avoid the access if its within a MAX_ORDER >> page. We could probably go for a smaller setting there. PAGE_COSTLY_ORDER? > > That is the solution to avoid compound_order() call when slab of > object isn't matched with per cpu slab. > > What I'm asking is whether there is a way to avoid compound_order() call when slab > of object is matched with per cpu slab or not. >
Can we use page->objects for that?
Like this:
return d > 0 && d < page->objects * s->size;
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