From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: linux-next: manual merge of the akpm tree with Linus' tree Date: Wed, 7 Mar 2012 23:32:20 -0800 Message-ID: <20120307233220.5a76aa3c.akpm@linux-foundation.org> References: <20120308175307.b295b1013728a5666fe4571a@canb.auug.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mail.linuxfoundation.org ([140.211.169.12]:55511 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751993Ab2CHHaS (ORCPT ); Thu, 8 Mar 2012 02:30:18 -0500 In-Reply-To: <20120308175307.b295b1013728a5666fe4571a@canb.auug.org.au> Sender: linux-next-owner@vger.kernel.org List-ID: To: Stephen Rothwell Cc: linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, Linus On Thu, 8 Mar 2012 17:53:07 +1100 Stephen Rothwell wrote: > Hi Andrew, > > Today's linux-next merge of the akpm tree got a conflict in > arch/x86/mm/hugetlbpage.c between commit 097d59106a8e ("vm: avoid using > find_vma_prev() unnecessarily") from Linus' tree and commit "hugetlb: > drop prev_vma in hugetlb_get_unmapped_area_topdown()" from the akpm tree. > > I think the latter is a superset of the former, so I just dropped the > changes from the former. Actually they're different. I reworked the earlier patch as below. From: Xiao Guangrong Subject: hugetlb: drop prev_vma in hugetlb_get_unmapped_area_topdown() After the call find_vma_prev(mm, addr, &prev_vma), the following condition is always true: !prev_vma || (addr >= prev_vma->vm_end) it can happily drop prev_vma and use find_vma() instead of find_vma_prev(). Signed-off-by: Xiao Guangrong Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Michal Hocko Cc: Hillf Danton Cc: Andrea Arcangeli Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton --- arch/x86/mm/hugetlbpage.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) diff -puN arch/x86/mm/hugetlbpage.c~hugetlb-drop-prev_vma-in-hugetlb_get_unmapped_area_topdown arch/x86/mm/hugetlbpage.c --- a/arch/x86/mm/hugetlbpage.c~hugetlb-drop-prev_vma-in-hugetlb_get_unmapped_area_topdown +++ a/arch/x86/mm/hugetlbpage.c @@ -308,7 +308,7 @@ static unsigned long hugetlb_get_unmappe { struct hstate *h = hstate_file(file); struct mm_struct *mm = current->mm; - struct vm_area_struct *vma, *prev_vma; + struct vm_area_struct *vma; unsigned long base = mm->mmap_base, addr = addr0; unsigned long largest_hole = mm->cached_hole_size; int first_time = 1; @@ -334,25 +334,16 @@ try_again: * i.e. return with success: */ vma = find_vma(mm, addr); - if (!vma) - return addr; - - /* - * new region fits between prev_vma->vm_end and - * vma->vm_start, use it: - */ - prev_vma = vma->vm_prev; - if (addr + len <= vma->vm_start && - (!prev_vma || (addr >= prev_vma->vm_end))) { + if (vma) + prev_vma = vma->vm_prev; + if (!vma || addr + len <= vma->vm_start) { /* remember the address as a hint for next time */ mm->cached_hole_size = largest_hole; return (mm->free_area_cache = addr); - } else { + } else if (mm->free_area_cache == vma->vm_end) { /* pull free_area_cache down to the first hole */ - if (mm->free_area_cache == vma->vm_end) { - mm->free_area_cache = vma->vm_start; - mm->cached_hole_size = largest_hole; - } + mm->free_area_cache = vma->vm_start; + mm->cached_hole_size = largest_hole; } /* remember the largest hole we saw so far */ _