From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx191.postini.com [74.125.245.191]) by kanga.kvack.org (Postfix) with SMTP id 0D4A96B0032 for ; Fri, 12 Jul 2013 14:38:35 -0400 (EDT) Message-ID: <51E04D1E.8060303@parallels.com> Date: Fri, 12 Jul 2013 22:38:22 +0400 From: Pavel Emelyanov MIME-Version: 1.0 Subject: Re: [PATCH 4/5] mm: soft-dirty bits for user memory changes tracking References: <517FED13.8090806@parallels.com> <517FED64.4020400@parallels.com> <51DEFD9E.7010703@mit.edu> In-Reply-To: <51DEFD9E.7010703@mit.edu> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andy Lutomirski Cc: Linus Torvalds , Andrew Morton , Glauber Costa , KOSAKI Motohiro , Matt Mackall , Marcelo Tosatti , Xiao Guangrong , Linux Kernel Mailing List , Linux MM On 07/11/2013 10:46 PM, Andy Lutomirski wrote: > > Sorry I'm late to the party -- I didn't notice this until the lwn > article this week. > > How does this get munmap + mmap right? mremap marks things soft-dirty, > but unmapping and remapping seems like it will result in the soft-dirty > bit being cleared. For that matter, won't this sequence also end up wrong: > > - clear_refs > - Write to mapping > - Page and pte evicted due to memory pressure > - Read from mapping -- clean page faulted back in > - pte soft-dirty is now clear ?!? Yes, it looks like this problem exists. I'll look what can be done about it, thank you. > --Andy Pavel -- 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