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Thu, 17 Jul 2025 17:08:36 -0700 (PDT) Date: Fri, 18 Jul 2025 00:08:35 +0000 From: Wei Yang To: wang lian Cc: akpm@linux-foundation.org, broonie@kernel.org, david@redhat.com, lorenzo.stoakes@oracle.com, sj@kernel.org, ziy@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, brauner@kernel.org, gkwang@linx-info.com, jannh@google.com, Liam.Howlett@oracle.com, ludovico.zy.wu@gmail.com, p1ucky0923@gmail.com, richard.weiyang@gmail.com, ryncsn@gmail.com, shuah@kernel.org, vbabka@suse.cz, zijing.zhang@proton.me Subject: Re: [PATCH 1/2] selftests/mm: reuse FORCE_READ to replace "asm volatile("" : "+r" (XXX));" Message-ID: <20250718000835.65qaxtwfgwborgls@master> Reply-To: Wei Yang References: <20250717131857.59909-1-lianux.mm@gmail.com> <20250717131857.59909-2-lianux.mm@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250717131857.59909-2-lianux.mm@gmail.com> User-Agent: NeoMutt/20170113 (1.7.2) X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 7E37B40006 X-Stat-Signature: iac6iw6k76max8mo8yrqac84xiur3cyp X-HE-Tag: 1752797318-150201 X-HE-Meta: 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 lI7mznr0 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jul 17, 2025 at 09:18:56PM +0800, wang lian wrote: >Several mm selftests use the `asm volatile("" : "+r" (variable));` >construct to force a read of a variable, preventing the compiler from >optimizing away the memory access. This idiom is cryptic and duplicated >across multiple test files. > >Following a suggestion from David[1], this patch refactors this >common pattern into a FORCE_READ() macro > >[1] https://lore.kernel.org/lkml/4a3e0759-caa1-4cfa-bc3f-402593f1eee3@redhat.com/ > >Signed-off-by: wang lian >Reviewed-by: Lorenzo Stoakes Reviewed-by: Wei Yang -- Wei Yang Help you, Help me