From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4255B13E.8080809@engr.sgi.com> Date: Thu, 07 Apr 2005 17:16:30 -0500 From: Ray Bryant MIME-Version: 1.0 Subject: question on page-migration code Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Hirokazu Takahashi Cc: Marcelo Tosatti , Dave Hansen , linux-mm List-ID: Hirokazu (and Marcelo), In testing my manual page migration code, I've run up against a situation where the migrations are occasionally very slow. They work ok, but they can take minutes to migrate a few megabytes of memory. Dropping into kdb shows that the migration code is waiting in msleep() in migrate_page_common() due to an -EAGAIN return from page_migratable(). A little further digging shows that the specific return in page_migratable() is the very last one there at the bottom of the routine. I'm puzzled as to why the page is still busy in this case. Previous code in page_migratable() has unmapped the page, its not in PageWriteback() because we would have taken a different return statement in that case. According to /proc/meminfo, there are no pages in either SwapCache or Dirty state, and the system has been sync'd before the migrate_pages() call was issued. -- 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