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[141.239.149.160]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2ccf7b2c5edsm7366670a91.3.2024.07.22.11.15.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jul 2024 11:15:41 -0700 (PDT) Date: Mon, 22 Jul 2024 08:15:40 -1000 From: Tejun Heo To: Boqun Feng Cc: kernel test robot , Suren Baghdasaryan , oe-lkp@lists.linux.dev, lkp@intel.com, linux-kernel@vger.kernel.org, Andrew Morton , Kent Overstreet , Kees Cook , Alexander Viro , Alex Gaynor , Alice Ryhl , Andreas Hindborg , Benno Lossin , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Christoph Lameter , Dennis Zhou , Gary Guo , Miguel Ojeda , Pasha Tatashin , Peter Zijlstra , Vlastimil Babka , Wedson Almeida Filho , linux-mm@kvack.org, lkmm@lists.linux.dev Subject: Re: [linus:master] [mm] 24e44cc22a: BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_block_update_hint_alloc Message-ID: References: <202407191651.f24e499d-oliver.sang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: BB1B1180013 X-Stat-Signature: aehgtp9tk9ehzjrhaemjkj1tjjkr8dtk X-HE-Tag: 1721672143-538963 X-HE-Meta: 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 FWWfg6aQ 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000077, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hello, On Mon, Jul 22, 2024 at 11:03:00AM -0700, Boqun Feng wrote: ... > For READ/WRITE_ONCE(), we will need to replace all write accesses and > all out-of-lock read accesses to pcpu_nr_empty_pop_pages, like below. > It's better in the sense that it doesn't rely on compiler behaviors on > data races, not sure about the performance impact though. The patch looks great and I doubt this would impact performance in any noticeable way. Thanks. -- tejun