From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <420A7728.4060109@sgi.com> Date: Wed, 09 Feb 2005 14:48:40 -0600 From: Ray Bryant MIME-Version: 1.0 Subject: Re: migration cache, updated References: <4207D59F.3060807@sgi.com> <20050208.111733.02298664.taka@valinux.co.jp> <42083913.9050306@sgi.com> <20050209.151938.63052333.taka@valinux.co.jp> In-Reply-To: <20050209.151938.63052333.taka@valinux.co.jp> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Hirokazu Takahashi , linux-mm@kvack.org Cc: marcelo.tosatti@cyclades.com List-ID: Hirokazu and Marcello, Here's some more information on this problem I am having with the migration cache. (The problem is that the test application is failing after it returns from the system call that migrated some of its address space from node 0 to node 3 on my test box. When the program touches the first page in the range that was migrated, the process gets killed because do_swap_page() returns VM_FAULT_OOM. The test works fine if I remove the migration cache patch.) It looks like the page is flagged as being a migration pte, the page is found in the migration cache, but then the test "likely(pte_same(*page_table, orig_pte))" succeeds. It's not obvious to me, at the moment, what this is supposed to be doing. Here is the code segment from do_swap_page(), with the debug printout that was triggered: again: if (pte_is_migration(orig_pte)) { page = lookup_migration_cache(entry.val); if (!page) { spin_lock(&mm->page_table_lock); page_table = pte_offset_map(pmd, address); if (likely(pte_same(*page_table, orig_pte))) { ==========================> DEBUG_VM_KILL(address); ret = VM_FAULT_OOM; } else ret = VM_FAULT_MINOR; pte_unmap(page_table); spin_unlock(&mm->page_table_lock); goto out; } -- Best Regards, Ray ----------------------------------------------- Ray Bryant 512-453-9679 (work) 512-507-7807 (cell) raybry@sgi.com raybry@austin.rr.com The box said: "Requires Windows 98 or better", so I installed Linux. ----------------------------------------------- -- 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: aart@kvack.org