From mboxrd@z Thu Jan 1 00:00:00 1970 From: kanoj@google.engr.sgi.com (Kanoj Sarcar) Message-Id: <200004082321.QAA01209@google.engr.sgi.com> Subject: Re: [patch] take 2 Re: PG_swap_entry bug in recent kernels Date: Sat, 8 Apr 2000 16:21:17 -0700 (PDT) In-Reply-To: from "Andrea Arcangeli" at Apr 09, 2000 01:10:19 AM MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrea Arcangeli Cc: Ben LaHaise , riel@nl.linux.org, Linus Torvalds , linux-mm@kvack.org List-ID: > > I was talking about the locking order issue you raised about the necessary > vmlist_*_lock I added in swapoff. > > What I meant is that in 2.2.x there was no need of the > vmlist_*_lock/page_cache_lock in swapoff because we was relying on the big > kernel lock while playing with pagetables and vmas (same in swap_out()). > > In 2.3.x both swap_out and swapoff needs to grab first the tasklist_lock > (as in 2.2.x) and then the vmlist_*_lock (otherwise as first the vma > browsing may happen during a vma list modification). > > Andrea > As I mentioned before, have you stress tested this to make sure grabbing read_lock(tasklist_lock), then spin_lock(vmlist_lock) is not deadlock prone? I _think_ you will run into problems ... and we can then stop discussing this. Kanoj -- 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/