From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx141.postini.com [74.125.245.141]) by kanga.kvack.org (Postfix) with SMTP id 700046B13F4 for ; Tue, 7 Feb 2012 19:33:48 -0500 (EST) Received: by pbcwz17 with SMTP id wz17so105669pbc.14 for ; Tue, 07 Feb 2012 16:33:47 -0800 (PST) Date: Tue, 7 Feb 2012 16:33:18 -0800 (PST) From: Hugh Dickins Subject: Re: [PATCH] mm: fix UP THP spin_is_locked BUGs In-Reply-To: <20120207161209.52d065e1.akpm@linux-foundation.org> Message-ID: References: <20120207161209.52d065e1.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Andrea Arcangeli , linux-mm@kvack.org On Tue, 7 Feb 2012, Andrew Morton wrote: > On Tue, 7 Feb 2012 16:00:46 -0800 (PST) > Hugh Dickins wrote: > > > +++ linux/mm/huge_memory.c 2012-02-07 15:37:18.581666053 -0800 > > @@ -2083,7 +2083,7 @@ static void collect_mm_slot(struct mm_sl > > { > > struct mm_struct *mm = mm_slot->mm; > > > > - VM_BUG_ON(!spin_is_locked(&khugepaged_mm_lock)); > > + VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); > > We do have assert_spin_locked(), but I couldn't see any way of using it > while observing these laziness constraints ;) ;) I didn't know about assert_spin_locked(). Hmm, fs/dcache.c seems to be using that successfully. We could forget about the VM_ part of it and respin the patch with assert_spin_locked(). I don't really mind either way: but happy to let laziness win the day - I'm back on an SMP kernel by now anyway. > > Should we patch -stable too? People seem to have survived very well without it so far, I think it's an unusual config combination, and quickly obvious if anyone hits it. But I've no objection if you think it deserves -stable. 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org