lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 6 Sep 2018 02:29:17 -0700 From: Eric Dumazet <eric.dumazet@...il.com> To: Vlad Buslov <vladbu@...lanox.com>, Kirill Tkhai <ktkhai@...tuozzo.com> Cc: netdev@...r.kernel.org, jhs@...atatu.com, xiyou.wangcong@...il.com, jiri@...nulli.us, davem@...emloft.net, stephen@...workplumber.org, paulmck@...ux.vnet.ibm.com, nicolas.dichtel@...nd.com, leon@...nel.org, gregkh@...uxfoundation.org, mark.rutland@....com, fw@...len.de, dsahern@...il.com, lucien.xin@...il.com, jakub.kicinski@...ronome.com, christian.brauner@...ntu.com, jbenc@...hat.com Subject: Re: [PATCH net-next 03/13] net: sched: extend Qdisc with rcu On 09/06/2018 02:23 AM, Vlad Buslov wrote: > > On Thu 06 Sep 2018 at 08:39, Kirill Tkhai <ktkhai@...tuozzo.com> wrote: >> On 06.09.2018 11:30, Eric Dumazet wrote: >>> >>> >>> On 09/06/2018 12:58 AM, Vlad Buslov wrote: >>> >>> ... >>> >>>> diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h >>>> index 18e22a5a6550..239c73f29471 100644 >>>> --- a/include/net/sch_generic.h >>>> +++ b/include/net/sch_generic.h >>>> @@ -90,6 +90,7 @@ struct Qdisc { >>>> struct gnet_stats_queue __percpu *cpu_qstats; >>>> int padded; >>>> refcount_t refcnt; >>>> + struct rcu_head rcu; >>>> >>>> /* >>>> * For performance sake on SMP, we put highly modified fields at the end >>> >>> Probably better to move this at the end of struct Qdisc, >>> not risking unexpected performance regressions in fast path. >> >> Do you mean regressions on UP? On SMP it looks like this field >> fits in the unused gap created by: >> >> struct sk_buff_head gso_skb ____cacheline_aligned_in_smp; >> >> Kirill > > Hi Eric, Kirill > > I intentionally put rcu_head here in order for it not to be in same > cache line with "highly modified fields" (according to comment). My personal preference would have been to use the last cache line for a new 'control path field', and leave holes in the first one for future needs in fast path. But this is a minor detail really, either choice is fine.
Powered by blists - more mailing lists