From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f197.google.com (mail-io0-f197.google.com [209.85.223.197]) by kanga.kvack.org (Postfix) with ESMTP id DFCEC6B035D for ; Fri, 23 Dec 2016 13:30:06 -0500 (EST) Received: by mail-io0-f197.google.com with SMTP id o11so56802946ioo.0 for ; Fri, 23 Dec 2016 10:30:06 -0800 (PST) Received: from resqmta-ch2-10v.sys.comcast.net (resqmta-ch2-10v.sys.comcast.net. [2001:558:fe21:29:69:252:207:42]) by mx.google.com with ESMTPS id 201si22175301ity.115.2016.12.23.10.30.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 23 Dec 2016 10:30:06 -0800 (PST) Date: Fri, 23 Dec 2016 12:30:02 -0600 (CST) From: Christoph Lameter Subject: Re: [PATCH] slub: do not merge cache if slub_debug contains a never-merge flag In-Reply-To: <20161222235959.GC6871@lp-laptop-d> Message-ID: References: <20161222235959.GC6871@lp-laptop-d> Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Grygorii Maistrenko Cc: linux-mm@kvack.org, Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton On Fri, 23 Dec 2016, Grygorii Maistrenko wrote: > In case CONFIG_SLUB_DEBUG_ON=n find_mergeable() gets debug features > from commandline but never checks if there are features from the > SLAB_NEVER_MERGE set. > As a result selected by slub_debug caches are always mergeable if they > have been created without a custom constructor set or without one of the > SLAB_* debug features on. WTF is this nonsense? That check is done a few lines earlier! struct kmem_cache *ind_mergeable(size_t size, size_t align, unsigned long flags, const char *name, void (*ctor)(void *)) { struct kmem_cache *s; if (slab_nomerge || (flags & SLAB_NEVER_MERGE)) <----- !!!!!! return NULL; if (ctor) return NULL; size = ALIGN(size, sizeof(void *)); align = calculate_alignment(flags, > > This adds the necessary check and makes selected slab caches unmergeable > if one of the SLAB_NEVER_MERGE features is set from commandline. > > Signed-off-by: Grygorii Maistrenko > --- > mm/slab_common.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 329b03843863..7341cba8c58b 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -266,6 +266,9 @@ struct kmem_cache *find_mergeable(size_t size, size_t align, > size = ALIGN(size, align); > flags = kmem_cache_flags(size, flags, name, NULL); > > + if (flags & SLAB_NEVER_MERGE) > + return NULL; > + > list_for_each_entry_reverse(s, &slab_caches, list) { > if (slab_unmergeable(s)) > continue; > -- 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