From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 3 Sep 2000 17:47:01 -0300 (BRST) From: Rik van Riel Subject: Re: Rik van Riel's VM patch In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Alan Cox Cc: Bill Huey , John Levon , linux-mm@kvack.org, "Theodore Y. Ts'o" , linux-kernel@vger.kernel.org List-ID: On Sun, 3 Sep 2000, Alan Cox wrote: > > Yes, it kicks butt and it finally (just about) removes the final > > Linux kernel showstopper for recent kernels. ;-) > > Things like random memory corruption from dropping dirty bits, > and some of the others are far more serious showstoppers alas Indeed, there are 4 major issues left in the VM area: 1) system hangs under load with 0 lowmem free (but still some high memory free) [not much details on this one yet] 2) dirty bits can get lost, try_to_swap_out() and other places have a race with the hardware [from mm/vmscan.c, line 60 has a race with the /hardware/] 55 if (pte_young(pte)) { 56 /* 57 * Transfer the "accessed" bit from the page 58 * tables to the global page map. 59 */ 60 set_pte(page_table, pte_mkold(pte)); 61 SetPageReferenced(page); 62 goto out_failed; 63 } 3) it appears something can corrupt page->count or delete a page from the cache while the page is locked [tripped up by my VM patch?] 4) the innd data corruption bug [anybody?] regards, Rik -- "What you're running that piece of shit Gnome?!?!" -- Miguel de Icaza, UKUUG 2000 http://www.conectiva.com/ http://www.surriel.com/ -- 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.eu.org/Linux-MM/