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AJvYcCW565+ZHQTy34K7hZ4WVue/g4G0w7JC8AnGN32CUCvuS+0u7rSfDLpgwykSP3ogRJXJ4pBxLiKcxg==@kvack.org X-Gm-Message-State: AOJu0YzO9OKoLcJRhNF1r72fTZxX+Woejqlq2/8OTkb8sxjIbNwE/CTq grjO2jm2R2a05g+WJIifuh/VU6xzbCA7PxVgQBRuWd1CF08aohz2wgmZnKz6pFfgXl5jy3lllPh 9y9ovpWGqNLB4/JeWYhalds2CbdxXGAo= X-Gm-Gg: ASbGnct2VnfSvi88FtJ0tOpmR8XXoJ17pJGsPFwmnq9yYLMy1bS+g7o7W1IS53Hw5eV k04O/aUiu5Bb2E1dp7clH2xgKl5iaIR927yUywt3wMBeHMI4mHCiWaxTuJkLBK2Z1jxE1q5hISw +7GUSn4gi3FgWytf3DYE652icmawHIOSi6ifPZoxPQi/DEesaAOCpXFJy/wADBUbeU8M5nOjgbY qpS5k7hSioeMQRg564bhatgaUOUIPsYihKfZXwewaHaOc9jHX7iiPzFreFkjiP89DqmT6Ax2sfT djd19wyK/g0lOc4vXXf/VmD7QewBr/F0nUas X-Google-Smtp-Source: AGHT+IHZzzEVWO5PSFfDM0hepN4yQvN1y0+nmWEUBQlDiGcXUbGHi5nbA08+gO7LBQf4rthVM0fgKbPH71PBos20E9w= X-Received: by 2002:a17:90b:1c86:b0:32b:8f2a:ae35 with SMTP id 98e67ed59e1d1-32b8f2aaf59mr3254587a91.1.1757023035654; Thu, 04 Sep 2025 14:57:15 -0700 (PDT) MIME-Version: 1.0 References: <20250828-rust-percpu-v3-0-4dd92e1e7904@gmail.com> <20250828-rust-percpu-v3-5-4dd92e1e7904@gmail.com> <68b9f5e2.170a0220.1224d9.5d3d@mx.google.com> <68b9ff1c.050a0220.35de1d.11b7@mx.google.com> In-Reply-To: <68b9ff1c.050a0220.35de1d.11b7@mx.google.com> From: Miguel Ojeda Date: Thu, 4 Sep 2025 23:57:02 +0200 X-Gm-Features: Ac12FXzzgEdE64V3Xyhcttg0HrRdfADWmugK1SarEVytCTaLM5JzuX5Un97wiHw Message-ID: Subject: Re: [PATCH v3 5/7] rust: percpu: Support non-zeroable types for DynamicPerCpu To: Mitchell Levy Cc: Yury Norov , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= , Andreas Hindborg , Alice Ryhl , Trevor Gross , Andrew Morton , Dennis Zhou , Tejun Heo , Christoph Lameter , Danilo Krummrich , Benno Lossin , Viresh Kumar , Tyler Hicks , linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: ECC7B100009 X-Stat-Signature: chrbjoa5p6ogeso5btwhswh7d45gd798 X-Rspam-User: X-HE-Tag: 1757023036-831157 X-HE-Meta: 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 SMNBPJzv 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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, Sep 4, 2025 at 11:05=E2=80=AFPM Mitchell Levy wrote: > > it *might* also be possible to use a macro and dispense with the need for > a closure, though I'm not familiar enough with proc macros to say for > sure. That would probably look like > > for_each_possible_cpu!(cpu) { > let remote_ptr =3D unsafe { ptr.get_remote_ptr(cpu) }; > // ... > } > > though personally I think the first one is better (simpler > implementation without too much syntactic overhead, especially since > closures are already used some within R4L). Yeah, please avoid macros as much as possible. Sometimes macros do have advantages, but if it is just to avoid a closure, then no, please avoid it. Similarly, unless there is a concrete advantage needed with the function, please avoid it too -- the original `for` with the iterator is the normal way of doing it and already used plenty in the kernel. Thanks! Cheers, Miguel