From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx189.postini.com [74.125.245.189]) by kanga.kvack.org (Postfix) with SMTP id D95546B0361 for ; Mon, 25 Jun 2012 11:30:38 -0400 (EDT) Date: Mon, 25 Jun 2012 17:30:35 +0200 From: Michal Hocko Subject: Re: [PATCH 2/5] mm/sparse: optimize sparse_index_alloc Message-ID: <20120625153035.GB19810@tiehlicka.suse.cz> References: <1340466776-4976-1-git-send-email-shangw@linux.vnet.ibm.com> <1340466776-4976-2-git-send-email-shangw@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1340466776-4976-2-git-send-email-shangw@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Gavin Shan Cc: linux-mm@kvack.org, rientjes@google.com, hannes@cmpxchg.org, akpm@linux-foundation.org On Sat 23-06-12 23:52:53, Gavin Shan wrote: > With CONFIG_SPARSEMEM_EXTREME, the two level of memory section > descriptors are allocated from slab or bootmem. When allocating > from slab, let slab allocator to clear the memory chunk. However, > the memory chunk from bootmem allocator, we have to clear that > explicitly. I am sorry but I do not see how this optimize the current code. What is the difference between slab doing memset and doing it explicitly for all cases? > > Signed-off-by: Gavin Shan > --- > mm/sparse.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/mm/sparse.c b/mm/sparse.c > index afd0998..ce50c8b 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -74,14 +74,14 @@ static struct mem_section noinline __init_refok *sparse_index_alloc(int nid) > > if (slab_is_available()) { > if (node_state(nid, N_HIGH_MEMORY)) > - section = kmalloc_node(array_size, GFP_KERNEL, nid); > + section = kzalloc_node(array_size, GFP_KERNEL, nid); > else > - section = kmalloc(array_size, GFP_KERNEL); > - } else > + section = kzalloc(array_size, GFP_KERNEL); > + } else { > section = alloc_bootmem_node(NODE_DATA(nid), array_size); > - > - if (section) > - memset(section, 0, array_size); > + if (section) > + memset(section, 0, array_size); > + } > > return section; > } > -- > 1.7.9.5 > > -- > 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 -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- 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