From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by wa-out-1112.google.com with SMTP id j37so1958990waf.22 for ; Wed, 29 Oct 2008 00:17:19 -0700 (PDT) Message-ID: <2f11576a0810290017g310e4469gd27aa857866849bd@mail.gmail.com> Date: Wed, 29 Oct 2008 16:17:19 +0900 From: "KOSAKI Motohiro" Subject: Re: [RFC][PATCH] lru_add_drain_all() don't use schedule_on_each_cpu() In-Reply-To: <1225229366.6343.74.camel@lts-notebook> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <2f11576a0810210851g6e0d86benef5d801871886dd7@mail.gmail.com> <2f11576a0810211018g5166c1byc182f1194cfdd45d@mail.gmail.com> <20081023235425.9C40.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20081027145509.ebffcf0e.akpm@linux-foundation.org> <20081028134536.9a7a5351.akpm@linux-foundation.org> <1225229366.6343.74.camel@lts-notebook> Sender: owner-linux-mm@kvack.org Return-Path: To: Lee Schermerhorn Cc: Andrew Morton , Christoph Lameter , heiko.carstens@de.ibm.com, npiggin@suse.de, linux-kernel@vger.kernel.org, hugh@veritas.com, torvalds@linux-foundation.org, riel@redhat.com, linux-mm@kvack.org List-ID: > I believe that we still have the lru_drain_all() called from the fault > path [with mmap_sem held] in clear_page_mlock(). We call > clear_page_mlock() on COW of an mlocked page in a VM_LOCKED vma to > ensure that we don't end up with an mlocked page in some other task's > non-VM_LOCKED vma where we'd then fail to munlock it later. During > development testing, Rik encountered scenarios where a page would > encounter a COW fault while it was still making its way to the LRU via > the pagevecs. So, he added the 'drain_all() and that seemed to avoid > this scenario. Agreed. > Now, in the current upstream version of the unevictable mlocked pages > patches, we just count any mlocked pages [vmstat] that make their way to > free*page() instead of BUGging out, as we were doing earlier during > development. So, maybe we can drop the lru_drain_add()s in the > unevictable mlocked pages work and live with the occasional freed > mlocked page, or mlocked page on the active/inactive lists to be dealt > with by vmscan. hm, okey. maybe, I was wrong. I'll make "dropping lru_add_drain_all()" patch soon. I expect I need few days. make the patch: 1 day confirm by stress workload: 2-3 days because rik's original problem only happend on heavy wokload, I think. -- 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