From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: SL*B: drop kmem cache argument from constructor From: Matt Mackall In-Reply-To: <20080711122228.eb40247f.akpm@linux-foundation.org> References: <20080710011132.GA8327@martell.zuzino.mipt.ru> <48763C60.9020805@linux.vnet.ibm.com> <20080711122228.eb40247f.akpm@linux-foundation.org> Content-Type: text/plain Date: Fri, 11 Jul 2008 14:38:34 -0500 Message-Id: <1215805114.4800.55.camel@calx> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Jon Tollefson , Alexey Dobriyan , penberg@cs.helsinki.fi, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cl@linux-foundation.org, Nick Piggin List-ID: On Fri, 2008-07-11 at 12:22 -0700, Andrew Morton wrote: > On Thu, 10 Jul 2008 11:44:16 -0500 Jon Tollefson wrote: > > > Alexey Dobriyan wrote: > > > Kmem cache passed to constructor is only needed for constructors that are > > > themselves multiplexeres. Nobody uses this "feature", nor does anybody uses > > > passed kmem cache in non-trivial way, so pass only pointer to object. > > > > > > Non-trivial places are: > > > arch/powerpc/mm/init_64.c > > > arch/powerpc/mm/hugetlbpage.c > > > > > ...... > > > --- a/arch/powerpc/mm/hugetlbpage.c > > > +++ b/arch/powerpc/mm/hugetlbpage.c > > > @@ -595,9 +595,9 @@ static int __init hugepage_setup_sz(char *str) > > > } > > > __setup("hugepagesz=", hugepage_setup_sz); > > > > > > -static void zero_ctor(struct kmem_cache *cache, void *addr) > > > +static void zero_ctor(void *addr) > > > { > > > - memset(addr, 0, kmem_cache_size(cache)); > > > + memset(addr, 0, HUGEPTE_TABLE_SIZE); > > > > > This isn't going to work with the multiple huge page size support. The > > HUGEPTE_TABLE_SIZE macro now takes a parameter with of the mmu psize > > index to indicate the size of page. > > > > hrm. I suppose we could hold our noses and use ksize(), assuming that > we're ready to use ksize() at this stage in the object's lifetime. ksize() on non-kmalloced objects is considered harmful. Doesn't work on SLOB. > Better would be to just use kmem_cache_zalloc()? I'd say so. -- Mathematics is the supreme nostalgia of our time. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org