From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx120.postini.com [74.125.245.120]) by kanga.kvack.org (Postfix) with SMTP id CCE796B004A for ; Thu, 1 Mar 2012 15:51:21 -0500 (EST) Date: Thu, 1 Mar 2012 12:51:19 -0800 From: Andrew Morton Subject: Re: [PATCH 2/2] ksm: cleanup: introduce ksm_check_mm() Message-Id: <20120301125119.dee770f8.akpm@linux-foundation.org> In-Reply-To: <1330594374-13497-2-git-send-email-lliubbo@gmail.com> References: <1330594374-13497-1-git-send-email-lliubbo@gmail.com> <1330594374-13497-2-git-send-email-lliubbo@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Bob Liu Cc: hughd@google.com, rientjes@google.com, kamezawa.hiroyu@jp.fujitsu.com, minchan.kim@gmail.com, linux-mm@kvack.org On Thu, 1 Mar 2012 17:32:54 +0800 Bob Liu wrote: > +static int ksm_check_mm(struct mm_struct *mm, struct vm_area_struct *vma, > + unsigned long addr) > +{ > + if (ksm_test_exit(mm)) > + return 0; > + vma = find_vma(mm, addr); > + if (!vma || vma->vm_start > addr) > + return 0; > + if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma) > + return 0; > + return 1; > +} Can we please think of a suitable name for this check, other than "check"? IOW, give the function a meaningful name which describes what it is checking? And it's not checking the mm, is it? It is checking the address: to see whether it lies within a mergeable anon vma. So maybe --- a/mm/ksm.c~ksm-cleanup-introduce-ksm_check_mm-fix +++ a/mm/ksm.c @@ -375,17 +375,17 @@ static int break_ksm(struct vm_area_stru return (ret & VM_FAULT_OOM) ? -ENOMEM : 0; } -static int ksm_check_mm(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long addr) +static bool in_mergeable_anon_vma(struct mm_struct *mm, + struct vm_area_struct *vma, unsigned long addr) { if (ksm_test_exit(mm)) - return 0; + return false; vma = find_vma(mm, addr); if (!vma || vma->vm_start > addr) - return 0; + return false; if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma) - return 0; - return 1; + return false; + return true; } static void break_cow(struct rmap_item *rmap_item) @@ -401,7 +401,7 @@ static void break_cow(struct rmap_item * put_anon_vma(rmap_item->anon_vma); down_read(&mm->mmap_sem); - if (ksm_check_mm(mm, vma, addr)) + if (in_mergeable_anon_vma(mm, vma, addr)) break_ksm(vma, addr); up_read(&mm->mmap_sem); } @@ -428,7 +428,7 @@ static struct page *get_mergeable_page(s struct page *page; down_read(&mm->mmap_sem); - if (!ksm_check_mm(mm, vma, addr)) + if (!in_mergeable_anon_vma(mm, vma, addr)) goto out; page = follow_page(vma, addr, FOLL_GET); _ -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org