From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758303AbYEEJ1s (ORCPT ); Mon, 5 May 2008 05:27:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754437AbYEEJ1k (ORCPT ); Mon, 5 May 2008 05:27:40 -0400 Received: from ecfrec.frec.bull.fr ([129.183.4.8]:49025 "EHLO ecfrec.frec.bull.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754197AbYEEJ1j (ORCPT ); Mon, 5 May 2008 05:27:39 -0400 Message-ID: <481ED2D9.3040801@bull.net> Date: Mon, 05 May 2008 11:26:49 +0200 From: Nadia Derbey Organization: BULL/DT/OSwR&D/Linux User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040115 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andrew Morton Cc: manfred@colorfullife.com, paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, efault@gmx.de Subject: Re: [PATCH 01/10] Fix idr_remove() References: <20080429143304.741001000@bull.net> <20080429143728.563232000@bull.net> <20080429114425.ea0e2f62.akpm@linux-foundation.org> In-Reply-To: <20080429114425.ea0e2f62.akpm@linux-foundation.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > On Tue, 29 Apr 2008 16:33:05 +0200 > Nadia.Derbey@bull.net wrote: > > >>[PATCH 01/10] >> >>This patch fixes idr_remove(): the return inside the loop makes us free only >>a single layer. >> >>Signed-off-by: Nadia Derbey >> >>--- >> lib/idr.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >>Index: linux-2.6.25-mm1/lib/idr.c >>=================================================================== >>--- linux-2.6.25-mm1.orig/lib/idr.c 2008-04-25 15:29:00.000000000 +0200 >>+++ linux-2.6.25-mm1/lib/idr.c 2008-04-25 15:48:34.000000000 +0200 >>@@ -385,8 +385,8 @@ void idr_remove(struct idr *idp, int id) >> while (idp->id_free_cnt >= IDR_FREE_MAX) { >> p = alloc_layer(idp); >> kmem_cache_free(idr_layer_cache, p); >>- return; >> } >>+ return; >> } >> EXPORT_SYMBOL(idr_remove); > > > erk, ancient bug. > > I _think_ the implications of this are that an idr tree will grow fatter > than it needs to be, but there is no permanent leak: idr_destroy() will > still free everything, yes? Yes, exactly. Actually, I've not checked whether all the kernel components call idr_destroy() when needed. > > And a consequence of the fix is that idr manipulations will now result in > more allocs and frees, Not necessarily more allocs: this loop keeps IDR_FREE_MAX layers in the free list. So idr_pre_get() should be a noop. > but the amount of memory which a tree uses will be > less? > > > Regards, Nadia