From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f180.google.com (mail-qk0-f180.google.com [209.85.220.180]) by kanga.kvack.org (Postfix) with ESMTP id AF5036B007E for ; Sat, 9 Apr 2016 08:34:42 -0400 (EDT) Received: by mail-qk0-f180.google.com with SMTP id o6so54127212qkc.2 for ; Sat, 09 Apr 2016 05:34:42 -0700 (PDT) Received: from mail-qg0-x230.google.com (mail-qg0-x230.google.com. [2607:f8b0:400d:c04::230]) by mx.google.com with ESMTPS id t26si13547126qki.113.2016.04.09.05.34.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 09 Apr 2016 05:34:41 -0700 (PDT) Received: by mail-qg0-x230.google.com with SMTP id j35so111199521qge.0 for ; Sat, 09 Apr 2016 05:34:41 -0700 (PDT) Message-ID: <1460205278.6473.486.camel@edumazet-glaptop3.roam.corp.google.com> Subject: Re: [Lsf] [LSF/MM TOPIC] Generic page-pool recycle facility? From: Eric Dumazet Date: Sat, 09 Apr 2016 05:34:38 -0700 In-Reply-To: <20160409111132.781a11b6@redhat.com> References: <1460034425.20949.7.camel@HansenPartnership.com> <20160407161715.52635cac@redhat.com> <1460042309.6473.414.camel@edumazet-glaptop3.roam.corp.google.com> <20160409111132.781a11b6@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Jesper Dangaard Brouer Cc: James Bottomley , Tom Herbert , Brenden Blanco , lsf@lists.linux-foundation.org, linux-mm , "netdev@vger.kernel.org" , lsf-pc@lists.linux-foundation.org, Alexei Starovoitov On Sat, 2016-04-09 at 11:11 +0200, Jesper Dangaard Brouer wrote: > Hi Eric, > Above code is okay. But do you think we also can get away with the same > trick we do with the SKB refcnf? Where we avoid an atomic operation if > refcnt==1. > > void kfree_skb(struct sk_buff *skb) > { > if (unlikely(!skb)) > return; > if (likely(atomic_read(&skb->users) == 1)) > smp_rmb(); > else if (likely(!atomic_dec_and_test(&skb->users))) > return; > trace_kfree_skb(skb, __builtin_return_address(0)); > __kfree_skb(skb); > } > EXPORT_SYMBOL(kfree_skb); No we can not use this trick this for pages : https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ec91698360b3818ff426488a1529811f7a7ab87f -- 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