From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 280D36B004D for ; Tue, 24 Mar 2009 14:24:36 -0400 (EDT) Date: Tue, 24 Mar 2009 19:39:40 +0100 From: Ingo Molnar Subject: Re: [patch 8/9] LTTng instrumentation - filemap Message-ID: <20090324183940.GI31117@elte.hu> References: <20090324155625.420966314@polymtl.ca> <20090324160149.029092843@polymtl.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090324160149.029092843@polymtl.ca> Sender: owner-linux-mm@kvack.org To: Mathieu Desnoyers Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, ltt-dev@lists.casi.polymtl.ca, linux-mm@kvack.org, Dave Hansen , Masami Hiramatsu , Peter Zijlstra , "Frank Ch. Eigler" , Frederic Weisbecker , Hideo AOKI , Takashi Nishiie , Steven Rostedt , Eduard - Gabriel Munteanu List-ID: * Mathieu Desnoyers wrote: > Index: linux-2.6-lttng/mm/filemap.c > +DEFINE_TRACE(wait_on_page_start); > +DEFINE_TRACE(wait_on_page_end); These are extremely incomplete - to the level of being useless. To understand the lifetime of the pagecache, the following basic events have to be observed and instrumented: - create a new page - fill in a new page - dirty a page [when we know this] - request writeout of a page - clean a page / complete writeout - free a page due to MM pressure - free a page due to truncation/delete The following additional events are useful as well: - mmap a page to a user-space address - copy a page to a user-space address (read) - write to a page from a user-space address (write) - unmap a page from a user-space address - fault in a user-space mapped pagecache page optional: - shmem attach/detach events - shmem map/unmap events - hugetlb map/unmap events I'm sure i havent listed them all. Have a look at the function-graph tracer output to see what kind of basic events can happen to a pagecache page. Ingo -- 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