From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 19 Oct 2006 00:41:18 -0700 From: Andrew Morton Subject: Re: [PATCH] mm:D-cache aliasing issue in cow_user_page Message-Id: <20061019004118.37741cad.akpm@osdl.org> In-Reply-To: <20061019.002237.130236131.davem@davemloft.net> References: <20061018233302.a067d1e7.akpm@osdl.org> <20061019.000027.41635681.davem@davemloft.net> <20061019001747.7da58920.akpm@osdl.org> <20061019.002237.130236131.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: David Miller Cc: dmonakhov@openvz.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Thu, 19 Oct 2006 00:22:37 -0700 (PDT) David Miller wrote: > > > Architectures typically take care of this in copy_user_page() and > > > clear_user_page(). The absolutely depend upon those two routines > > > being used for anonymous pages, and handle the D-cache issues there. > > > > Only anonymous pages? There are zillions of places where we modify > > pagecache without a flush, especially against the blockdev mapping (fs > > metadata). > > It's cpu stores that matter, not device DMA and the like, and we have > flush_dcache_page() calls in the correct spots. You can see that > we take care of this even in places such as the loop driver :-) grep b_data fs/*/*.c All of them ;) It's possible to mmap /dev/hda, but it's a rather odd thing to do (INND can do it, but not a live filesystem). -- 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