Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263097AbTIHRbd (ORCPT ); Mon, 8 Sep 2003 13:31:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263376AbTIHRbd (ORCPT ); Mon, 8 Sep 2003 13:31:33 -0400 Received: from bay-bridge.veritas.com ([143.127.3.10]:54534 "EHLO mtvmime03.VERITAS.COM") by vger.kernel.org with ESMTP id S263097AbTIHRba (ORCPT ); Mon, 8 Sep 2003 13:31:30 -0400 Date: Mon, 8 Sep 2003 18:33:04 +0100 (BST) From: Hugh Dickins X-X-Sender: hugh@localhost.localdomain To: Rusty Russell cc: Ulrich Drepper , Jamie Lokier , Andrew Morton , Stephen Hemminger , Linus Torvalds , Linux Kernel Subject: Re: [PATCH] Re: today's futex changes In-Reply-To: <20030908102309.0AC4E2C013@lists.samba.org> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2088 Lines: 46 On Mon, 8 Sep 2003, Rusty Russell wrote: > OK, I've updated my patch on top of this. Mainly cosmetic, please > review. > > Name: Minor Tweaks To Jamie Lokier's Futex Patch > Author: Rusty Russell > Status: Booted on 2.6.0-test4-bk9 > Depends: Misc/futex-hugh.patch.gz > > D: Minor changes to Jamie's excellent futex patch. > D: 1) Remove obsolete comment above hash array decl. > D: 2) Semantics of futex on read-only pages unclear: require write perm. > D: 3) Clarify comment about TASK_INTERRUPTIBLE. > D: 4) Andrew Morton says spurious wakeup is a bug. Catch it. > D: 5) Use Jenkins hash. Most of it (the futex_wait tweaks) looked fine to me - though I look forward to the first report of that BUG(). Part 2, requiring VM_WRITE and removing the comment on VM_MAYSHARE, seems a regression to me. Perhaps I misinterpreted Linus' action in taking Jamie's patch: I took that to mean he relented a little on his hardline position about VM_SHARED, and now accepts that in this context VM_MAYSHARE is more appropriate (easier to document). I know I argued that readonly futices are pointless, but I thought Jamie gave a good picture of how a readonly view could still be used. I'd rather that part were a separate patch, so Linus can merge or not as he wishes. In part 5, the Jenkins hashing, I was puzzled by the "/4" in + (sizeof(key->both.word)+sizeof(key->both.ptr))/4, both.ptr would be a multiple of 32 (? seems to be that way on PIII and P4, though I gave up trying to work out quite how slab.c aligns), and both.word would be a multiple of 1 in the shared.pgoff case, or a multiple of PAGE_SIZE in the private.uaddr case (private.uaddr = uaddr >> PAGE_SHIFT might make more sense). Whereas both.offset would be a multiple of 4. I don't suppose Mr Jenkins will mind, but I did find the "/4" puzzling in that context. Hugh - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/