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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Shaokun Zhang <zhangshaokun@hisilicon.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	David Miller <davem@davemloft.net>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	jinyuqi@huawei.com, kuznet@ms2.inr.ac.ru,
	yoshfuji@linux-ipv6.org, edumazet@google.com,
	guoyang2@huawei.com, Will Deacon <will@kernel.org>
Subject: Re: [PATCH] net: optimize cmpxchg in ip_idents_reserve
Date: Fri, 17 Jan 2020 08:35:07 -0800	[thread overview]
Message-ID: <7e6c6202-24bb-a532-adde-d53dd6fb14c3@gmail.com> (raw)
In-Reply-To: <20200117123253.GC14879@hirez.programming.kicks-ass.net>



On 1/17/20 4:32 AM, Peter Zijlstra wrote:

> 
> That's crazy, just accept that UBSAN is taking bonghits and ignore it.
> Use atomic_add_return() unconditionally.
> 

Yes, we might simply add a comment so that people do not bug us if
their compiler is too old.

/* If UBSAN reports an error there, please make sure your compiler
 * supports -fno-strict-overflow before reporting it.
 */
return atomic_add_return(segs + delta, p_id) - segs;


  reply	other threads:[~2020-01-17 16:35 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-15  3:23 [PATCH] net: optimize cmpxchg in ip_idents_reserve Shaokun Zhang
2020-01-16 12:27 ` David Miller
2020-01-16 14:05   ` Shaokun Zhang
2020-01-16 15:12   ` Eric Dumazet
2020-01-16 15:19     ` Eric Dumazet
2020-01-17  6:54       ` Shaokun Zhang
2020-01-17 12:32         ` Peter Zijlstra
2020-01-17 16:35           ` Eric Dumazet [this message]
2020-01-17 18:03             ` Arvind Sankar
2020-01-17 18:16               ` Eric Dumazet
2020-01-17 18:38                 ` Arvind Sankar
2020-01-17 18:48                   ` Eric Dumazet
2020-01-20  8:18                     ` Peter Zijlstra
2020-05-07  9:12                       ` Shaokun Zhang
2020-05-07 13:49                         ` Eric Dumazet
2020-01-19  3:46           ` Shaokun Zhang
2020-01-19  4:12             ` Eric Dumazet
2020-01-21  2:40               ` Shaokun Zhang
2020-01-22  8:49               ` Peter Zijlstra

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