From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <425AC932.2030300@engr.sgi.com> Date: Mon, 11 Apr 2005 14:00:02 -0500 From: Ray Bryant MIME-Version: 1.0 Subject: Re: question on page-migration code References: <4255B13E.8080809@engr.sgi.com> <20050407180858.GB19449@logos.cnet> In-Reply-To: <20050407180858.GB19449@logos.cnet> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Marcelo Tosatti Cc: Hirokazu Takahashi , Dave Hansen , linux-mm List-ID: Marcelo Tosatti wrote: > Who is using the page? > > A little debugging might help similar to what bad_page does can help: > > printk(KERN_EMERG "flags:0x%0*lx mapping:%p mapcount:%d count:%d\n", > (int)(2*sizeof(page_flags_t)), (unsigned long)page->flags, > page->mapping, page_mapcount(page), page_count(page)); > -- Marcello, I wrote: "PagePrivate() is cleared by truncation specific code in migrate_onepage(), but it doesn't appear to be cleared (directly) by code on the generic_migrate_page() patch. I wonder if this has something to do with the problem I am seeing. " Ooops. I didn't look deep enough. migrate_page_common() calls writeback_and_free_buffers(), which in turn calls try_to_release_page() which will eventually call down to __clear_page_buffers() which will clear PagePrivate(). So it looks like the following is perhaps what is happening: (1) We come into migrate_one_page() with the pages dirty. (The first time we enter the -EAGAIN section of migate_page_common() we have flags = 105d, the last time through before succeeding, flags are 104d, and when we do return flags=004d. (2) We have to wait around until the pages get paged out before we can migrated them. (flags=004d). I'll have to check and see if I believe it might take 3 minutes to page out all of the pages of my application. If so, then this explains what is happening. Does that make sense? -- 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