From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f53.google.com (mail-pb0-f53.google.com [209.85.160.53]) by kanga.kvack.org (Postfix) with ESMTP id 2D0656B0039 for ; Thu, 29 May 2014 05:06:26 -0400 (EDT) Received: by mail-pb0-f53.google.com with SMTP id md12so53387pbc.26 for ; Thu, 29 May 2014 02:06:25 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTP id tu2si23075pbc.173.2014.05.29.02.06.24 for ; Thu, 29 May 2014 02:06:25 -0700 (PDT) Date: Thu, 29 May 2014 02:04:43 -0700 From: Andrew Morton Subject: Re: [PATCH] mm: dont call mmu_notifier_invalidate_page during munlock Message-Id: <20140529020443.974b0d1b.akpm@linux-foundation.org> In-Reply-To: References: <20140528075955.20300.22758.stgit@zurg> <20140528160948.489fde6e0285885d13f7c656@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Konstantin Khlebnikov Cc: "linux-mm@kvack.org" , Linux Kernel Mailing List On Thu, 29 May 2014 11:19:27 +0400 Konstantin Khlebnikov wrote: > On Thu, May 29, 2014 at 3:09 AM, Andrew Morton > wrote: > > On Wed, 28 May 2014 11:59:55 +0400 Konstantin Khlebnikov wrote: > > > >> try_to_munlock() searches other mlocked vmas, it never unmaps pages. > >> There is no reason for invalidation because ptes are left unchanged. > >> > >> ... > >> > >> --- a/mm/rmap.c > >> +++ b/mm/rmap.c > >> @@ -1225,7 +1225,7 @@ int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, > >> > >> out_unmap: > >> pte_unmap_unlock(pte, ptl); > >> - if (ret != SWAP_FAIL) > >> + if (ret != SWAP_FAIL && TTU_ACTION(flags) != TTU_MUNLOCK) > >> mmu_notifier_invalidate_page(mm, address); > >> out: > >> return ret; > > > > The patch itself looks reasonable but there is no such thing as > > try_to_munlock(). I rewrote the changelog thusly: > > Wait, what? I do have function with this name in my sources. It calls rmap_walk > with callback try_to_unmap_one and action TTU_MUNLOCK. This is the place > where TTU_MUNLOCK is used, I've mentioned it as entry point of this logic. Ah OK, I obviously misgrepped. > > > > : In its munmap mode, try_to_unmap_one() searches other mlocked vmas, it > > : never unmaps pages. There is no reason for invalidation because ptes are > > : left unchanged. > > > > Also, the name try_to_unmap_one() is now pretty inaccurate/incomplete. > > Perhaps if someone is feeling enthusiastic they might think up a better > > name for the various try_to_unmap functions and see if we can > > appropriately document try_to_unmap_one(). > > I thought about moving mlock part out of try_to_unmap_one() into > separate function, > but normal unmap needs this part too... try_to_unmap_one() does appear to have enough in common with the munlock operation to justify using common code. But doing so makes the name wrong. -- 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