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Howlett" , linux-block@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 15/79] block: rnull: add `use_per_node_hctx` config option In-Reply-To: References: <20260216-rnull-v6-19-rc5-send-v1-0-de9a7af4b469@kernel.org> <20260216-rnull-v6-19-rc5-send-v1-15-de9a7af4b469@kernel.org> Date: Mon, 16 Mar 2026 14:57:47 +0100 Message-ID: <87cy13swpw.fsf@t14s.mail-host-address-is-not-set> MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Queue-Id: 3BAAA4000A X-Stat-Signature: wmc47s9xmmgxccswdeda348md6mg63c3 X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1773669480-931421 X-HE-Meta: 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 FJ1FNG+1 A14fUhd4xBMi+amFE16Ov1uQH3pMqtG1O/DxuWCm4lMT97vrTviBVE+Fy+qZKTYE1pIFftsl1L07f7i90dQx3LPSnE3PLD4Mbni25GryjwvOKMG84AZVOwPBJwVFXcVzg7gZl8YyLT3QHgWjCnG2avlDHpBLsIqTCTR1WPPiVO+/0EQX3ojL44pAPm8ZVAHYxKkaSHAEUXpAaozchmjbQ/x0rdXOppxIvFLCYCToyFkGSwvSxj/px32DniBd/JpgxsNgPq3A275NiVil3cBvag3hJtzN1T0KQ4QpZjNAk+riaEUOUMuxCeyv7+G+aIN3bOMI0UwGUV9Y8xV8= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: "Alice Ryhl" writes: > On Mon, Feb 16, 2026 at 12:35:02AM +0100, Andreas Hindborg wrote: >> Add a configfs attribute to enable per-NUMA-node hardware contexts. >> When enabled, the driver creates one hardware queue per NUMA node >> instead of the default configuration. >> >> Signed-off-by: Andreas Hindborg > > This and other patches make me think that module parameters should have > value() return a copy of the value (and require Copy). For non-copy > types, there can be a separate value_ref() method. You would avoid *so* > many asterisks by doing that. Makes sense, I'll send a patch. > >> +configfs_attribute!(DeviceConfig, 8, >> + show: |this, page| show_field( >> + this.data.lock().submit_queues == kernel::num_online_nodes(), page >> + ), >> + store: |this, page| store_with_power_check(this, page, |this, page| { >> + let value = core::str::from_utf8(page)? >> + .trim() >> + .parse::() >> + .map_err(|_| kernel::error::code::EINVAL)? >> + != 0; >> + >> + if value { >> + this.data.lock().submit_queues *= kernel::num_online_nodes(); >> + } > > kstrtobool again. Also, this is *multiplying* the existing submit_queues > value by the number of NUMA nodes? Yea, that is not right. Astrisk should be deref on the other side of the left hand expression. > >> + use_per_node_hctx: u8 { >> + default: 0, >> + description: >> + "Use per-node allocation for hardware context queues, 0-false, 1-true. Default: 0-false", >> + }, > > formatting (rustfmt ignores macros) This is intentional. The line gets too long if I pull it up, and I don't think I can break the string in any way. I think it would require changes to the module parameter macro. Best regards, Andreas Hindborg