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 SMTP id AFD316B00AB for ; Mon, 28 Sep 2009 12:42:34 -0400 (EDT) Date: Sun, 27 Sep 2009 22:57:29 +0100 (BST) From: Hugh Dickins Subject: Re: [RFC][PATCH] HWPOISON: remove the unsafe __set_page_locked() In-Reply-To: <20090927192251.GB6327@wotan.suse.de> Message-ID: References: <20090926031537.GA10176@localhost> <20090926190645.GB14368@wotan.suse.de> <20090926213204.GX30185@one.firstfloor.org> <20090927192251.GB6327@wotan.suse.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Nick Piggin Cc: Andi Kleen , Wu Fengguang , Andrew Morton , linux-mm@kvack.org, LKML List-ID: On Sun, 27 Sep 2009, Nick Piggin wrote: > On Sun, Sep 27, 2009 at 05:26:25PM +0100, Hugh Dickins wrote: > > > > I don't particularly like adding a GFP_LOCKED just for this, and I > > don't particularly like having to remember to unlock the thing on the > > various(?) error paths between getting the page and adding it to cache. > > God no, please no more crazy branches in the page allocator. > > I'm going to resubmit my patches to allow 0-ref page allocations, > so the pagecache will be able to work with those to do what we > want here. > > > But it is a good idea, and if doing it that way would really close a > > race window which checking page->mapping (or whatever) cannot (I'm > > simply not sure about that), then it would seem the best way to go. > > Yep, seems reasonable: the ordering is no technical burden, and a > simple comment pointing to hwpoison will keep it maintainable. You move from "God no" to "Yep, seems reasonable"! I think perhaps you couldn't bring yourself to believe that I was giving any support to Andi's GFP_LOCKED idea. Pretend I did not! I'll assume we stick with the "God no", and we'll see how what you come up with affects what they want. Hugh -- 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