From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx175.postini.com [74.125.245.175]) by kanga.kvack.org (Postfix) with SMTP id D05BA6B005C for ; Wed, 7 Aug 2013 02:08:12 -0400 (EDT) Date: Wed, 7 Aug 2013 02:08:03 -0400 From: Johannes Weiner Subject: Re: [PATCH 2/4] mm, rmap: allocate anon_vma_chain before starting to link anon_vma_chain Message-ID: <20130807060803.GJ1845@cmpxchg.org> References: <1375778620-31593-1-git-send-email-iamjoonsoo.kim@lge.com> <1375778620-31593-2-git-send-email-iamjoonsoo.kim@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1375778620-31593-2-git-send-email-iamjoonsoo.kim@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: Joonsoo Kim Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim , Minchan Kim , Mel Gorman , Rik van Riel , Michel Lespinasse On Tue, Aug 06, 2013 at 05:43:38PM +0900, Joonsoo Kim wrote: > If we allocate anon_vma_chain before starting to link, we can reduce > the lock hold time. This patch implement it. > > Signed-off-by: Joonsoo Kim > > diff --git a/mm/rmap.c b/mm/rmap.c > index c2f51cb..1603f64 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -240,18 +240,21 @@ int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src) > { > struct anon_vma_chain *avc, *pavc; > struct anon_vma *root = NULL; > + LIST_HEAD(avc_list); > + > + list_for_each_entry(pavc, &src->anon_vma_chain, same_vma) { > + avc = anon_vma_chain_alloc(GFP_KERNEL); > + if (unlikely(!avc)) > + goto enomem_failure; > + > + list_add_tail(&avc->same_vma, &avc_list); > + } > > list_for_each_entry_reverse(pavc, &src->anon_vma_chain, same_vma) { > struct anon_vma *anon_vma; > > - avc = anon_vma_chain_alloc(GFP_NOWAIT | __GFP_NOWARN); > - if (unlikely(!avc)) { > - unlock_anon_vma_root(root); > - root = NULL; > - avc = anon_vma_chain_alloc(GFP_KERNEL); > - if (!avc) > - goto enomem_failure; > - } > + avc = list_entry((&avc_list)->next, typeof(*avc), same_vma); list_first_entry() please > + list_del(&avc->same_vma); > anon_vma = pavc->anon_vma; > root = lock_anon_vma_root(root, anon_vma); > anon_vma_chain_link(dst, avc, anon_vma); > @@ -259,8 +262,11 @@ int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src) > unlock_anon_vma_root(root); > return 0; > > - enomem_failure: > - unlink_anon_vmas(dst); > +enomem_failure: > + list_for_each_entry_safe(avc, pavc, &avc_list, same_vma) { > + list_del(&avc->same_vma); > + anon_vma_chain_free(avc); > + } > return -ENOMEM; > } Otherwise, looks good. Thanks! -- 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