From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f171.google.com (mail-ig0-f171.google.com [209.85.213.171]) by kanga.kvack.org (Postfix) with ESMTP id D48D16B0038 for ; Tue, 8 Sep 2015 13:32:41 -0400 (EDT) Received: by igxx6 with SMTP id x6so22048629igx.1 for ; Tue, 08 Sep 2015 10:32:41 -0700 (PDT) Received: from resqmta-ch2-06v.sys.comcast.net (resqmta-ch2-06v.sys.comcast.net. [2001:558:fe21:29:69:252:207:38]) by mx.google.com with ESMTPS id e36si3848238ioj.101.2015.09.08.10.32.41 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Tue, 08 Sep 2015 10:32:41 -0700 (PDT) Date: Tue, 8 Sep 2015 12:32:40 -0500 (CDT) From: Christoph Lameter Subject: Re: [RFC PATCH 0/3] Network stack, first user of SLAB/kmem_cache bulk free API. In-Reply-To: <20150905131825.6c04837d@redhat.com> Message-ID: References: <20150824005727.2947.36065.stgit@localhost> <20150904165944.4312.32435.stgit@devil> <55E9DE51.7090109@gmail.com> <55EA0172.2040505@gmail.com> <20150905131825.6c04837d@redhat.com> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Jesper Dangaard Brouer Cc: Alexander Duyck , netdev@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, aravinda@linux.vnet.ibm.com, "Paul E. McKenney" , iamjoonsoo.kim@lge.com On Sat, 5 Sep 2015, Jesper Dangaard Brouer wrote: > The double_cmpxchg without lock prefix still cost 9 cycles, which is > very fast but still a cost (add approx 19 cycles for a lock prefix). > > It is slower than local_irq_disable + local_irq_enable that only cost > 7 cycles, which the bulking call uses. (That is the reason bulk calls > with 1 object can almost compete with fastpath). Hmmm... Guess we need to come up with distinct version of kmalloc() for irq and non irq contexts to take advantage of that . Most at non irq context anyways. -- 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