Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932782AbbFIHKJ (ORCPT ); Tue, 9 Jun 2015 03:10:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53140 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753659AbbFIHKC (ORCPT ); Tue, 9 Jun 2015 03:10:02 -0400 Date: Tue, 9 Jun 2015 09:09:56 +0200 From: Jesper Dangaard Brouer To: Joonsoo Kim Cc: linux-kernel@vger.kernel.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, mm-commits@vger.kernel.org, brouer@redhat.com Subject: Re: + slub-bulk-alloc-extract-objects-from-the-per-cpu-slab.patch added to -mm tree Message-ID: <20150609090956.3345d9c8@redhat.com> In-Reply-To: <20150609002639.GB9687@js1304-P5Q-DELUXE> References: <5525b159.BpuUD6FQt89EaGh/%akpm@linux-foundation.org> <20150609002639.GB9687@js1304-P5Q-DELUXE> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4303 Lines: 115 On Tue, 9 Jun 2015 09:26:39 +0900 Joonsoo Kim wrote: > On Wed, Apr 08, 2015 at 03:53:13PM -0700, akpm@linux-foundation.org wrote: > > > > The patch titled > > Subject: slub bulk alloc: extract objects from the per cpu slab > > has been added to the -mm tree. Its filename is > > slub-bulk-alloc-extract-objects-from-the-per-cpu-slab.patch > > > > This patch should soon appear at > > http://ozlabs.org/~akpm/mmots/broken-out/slub-bulk-alloc-extract-objects-from-the-per-cpu-slab.patch > > and later at > > http://ozlabs.org/~akpm/mmotm/broken-out/slub-bulk-alloc-extract-objects-from-the-per-cpu-slab.patch > > > > Before you just go and hit "reply", please: > > a) Consider who else should be cc'ed > > b) Prefer to cc a suitable mailing list as well > > c) Ideally: find the original patch on the mailing list and do a > > reply-to-all to that, adding suitable additional cc's > > > > *** Remember to use Documentation/SubmitChecklist when testing your code *** > > > > The -mm tree is included into linux-next and is updated > > there every 3-4 working days > > > > ------------------------------------------------------ > > From: Christoph Lameter > > Subject: slub bulk alloc: extract objects from the per cpu slab > > > > First piece: acceleration of retrieval of per cpu objects > > > > If we are allocating lots of objects then it is advantageous to disable > > interrupts and avoid the this_cpu_cmpxchg() operation to get these objects > > faster. Note that we cannot do the fast operation if debugging is > > enabled. Note also that the requirement of having interrupts disabled > > avoids having to do processor flag operations. > > > > Allocate as many objects as possible in the fast way and then fall back to > > the generic implementation for the rest of the objects. > > > > Signed-off-by: Christoph Lameter > > Cc: Jesper Dangaard Brouer > > Cc: Christoph Lameter > > Cc: Pekka Enberg > > Cc: David Rientjes > > Cc: Joonsoo Kim > > Signed-off-by: Andrew Morton > > --- > > > > mm/slub.c | 27 ++++++++++++++++++++++++++- > > 1 file changed, 26 insertions(+), 1 deletion(-) > > > > diff -puN mm/slub.c~slub-bulk-alloc-extract-objects-from-the-per-cpu-slab mm/slub.c > > --- a/mm/slub.c~slub-bulk-alloc-extract-objects-from-the-per-cpu-slab > > +++ a/mm/slub.c > > @@ -2759,7 +2759,32 @@ EXPORT_SYMBOL(kmem_cache_free_bulk); > > bool kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, > > void **p) > > { > > - return kmem_cache_alloc_bulk(s, flags, size, p); > > + if (!kmem_cache_debug(s)) { > > + struct kmem_cache_cpu *c; > > + > > + /* Drain objects in the per cpu slab */ > > + local_irq_disable(); > > + c = this_cpu_ptr(s->cpu_slab); > > + > > + while (size) { > > + void *object = c->freelist; > > + > > + if (!object) > > + break; > > + > > + c->freelist = get_freepointer(s, object); > > + *p++ = object; > > + size--; > > + > > + if (unlikely(flags & __GFP_ZERO)) > > + memset(object, 0, s->object_size); > > + } > > + c->tid = next_tid(c->tid); > > + > > + local_irq_enable(); > > + } > > + > > + return __kmem_cache_alloc_bulk(s, flags, size, p); > > Hello, > > So, if __kmem_cache_alloc_bulk() fails, all allocated objects in array > should be freed, but, __kmem_cache_alloc_bulk() can't know > about objects allocated by this slub specific kmem_cache_alloc_bulk() > function. Please fix it. Check, I've already noticed this, and have fixed it in my local git tree. How do I submit a fix to AKPM? (do I replace the commit/patch, or do I apply a patch on top) (And as you also noticed, I've also moved the memset out of the loop, after irq_enable) -- Best regards, Jesper Dangaard Brouer MSc.CS, Sr. Network Kernel Developer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/