From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH v6] add MAP_UNLOCKED mmap flag Date: Tue, 19 Jan 2010 12:40:58 +0200 Message-ID: <20100119104058.GL14345@redhat.com> References: <20100118170816.GA22111@redhat.com> <84144f021001181009m52f7eaebp2bd746f92de08da9@mail.gmail.com> <20100118181942.GD22111@redhat.com> <20100118191031.0088f49a@lxorguk.ukuu.org.uk> <20100119071734.GG14345@redhat.com> <84144f021001182337o274c8ed3q8ce60581094bc2b9@mail.gmail.com> <20100119075205.GI14345@redhat.com> <84144f021001190007q54a334dfwed64189e6cf0b7c4@mail.gmail.com> <20100119082638.GK14345@redhat.com> <84144f021001190044s397c6665qb00af48235d2d818@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <84144f021001190044s397c6665qb00af48235d2d818@mail.gmail.com> Sender: owner-linux-mm@kvack.org To: Pekka Enberg Cc: Alan Cox , linux-mm@kvack.org, kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, akpm@linux-foundation.org, andrew.c.morrow@gmail.com, "Paul E. McKenney" , Rik van Riel , Johannes Weiner , minchan.kim@gmail.com List-Id: linux-api@vger.kernel.org On Tue, Jan 19, 2010 at 10:44:23AM +0200, Pekka Enberg wrote: > On Tue, Jan 19, 2010 at 10:26 AM, Gleb Natapov wrote: > >> me that you're trying to use a big hammer (mlock) when a polite hint > >> for the VM would probably be sufficient for it do its job. > >> > > I what to tell to VM "swap this, don't swap that" and as far as I see > > there is no other way to do it currently. > > Yeah, which is why I was suggesting that maybe posix_madvise() needs > to be extended to have a MADV_NEED_BUT_LESS_IMPORTANT flag that can be > used as a hint by mm/vmscan.c to first swap the guest address spaces. > If such thing would exist may be I would have used it since swapping out of a wrong page is not live or death matter in my case, but mlockall() provides me with exactly what I need and without swapping out wrong pages. Speaking about adding such madvise call wouldn't it be even harder to justify? It obviously not good enough for real-time use and my case, I admit, is unusual. Also if we start prioritise memory why stop on binary, why not set value like "this memory is more important then that memory by factor of 5"? -- Gleb. -- 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