From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8A19259C976 for ; Fri, 16 Oct 2026 18:03:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792173801; cv=none; b=W84Z+HAzNL9tGETOydHdHvxyVgMTA/ZMGbUngmfvpMQ3rFVVOqkKdWdWJwjPYYxBKkjeWoSDbajGaUXvOwnqEqixHYf+kxTnvtTDS8lyzK4yYIXHQ+S08FJPjKKMRA2fk0moVuGBx1MxkN3FbW4ccxrQn0K9F6pbTZgjCH3wfL0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792173801; c=relaxed/simple; bh=eM9ao6oAulDPYd6UEPWg93GZGjjztqDBossYWkJDlOs=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=kAh/oHkNHhMgFBbP6Ljc6AAqhhuvnrJj6eyc+RscmBDZCzzSYUQngyCNcEQvOevRtAvVl0yu7+i9YRktGKwXI+Mwo+okPfuS7GZP3FOFcpnqul4GgszLX9CrMzzVEID/LpzqcjMWpBvamuVd+Zs8Cf4R29hsgYrYgkSzY24Vilw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=N4ZYmPtx; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="N4ZYmPtx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 459D41F000C4; Fri, 16 Oct 2026 18:03:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792173800; bh=sY/vzPRyUSmg3b8tgu+9E+2fgPSs9yvbJDS5kTRiN3w=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=N4ZYmPtx87e0hxQTvy+D4P2kH1NpwFHRyec9xKfSxnNZf3//khZBY4xEkRK0DIxI4 g2aEqW1jgZv+e8JIW8PQ7pT1qa0qNcd4sFcdVCA/NE8vuOg0Ylof0NZESaKUIQVHFi jDT2Z+tvYI+b34Q4pcYcG45ugteipWujnt43JeaU6uA4RTVCvFtv4xz5KnTGw5j9BO mt34iej5Iu+Ws5J40TUfGHlUoYBU1WKrINvpUPYR+vOxyinRWVabR7Y+yoPA1ZU5BM fJPb9bSZr1832yOJWlj6aHcSMyfYEx3vGc6kZ10WsQRu6X8ySZX+4TCcazjKFpHUV9 U4zLlXVwbjI1g== Date: Fri, 16 Oct 2026 08:03:19 -1000 Message-ID: <2da5c0871093ae68069e60889a0481ca@kernel.org> From: Tejun Heo To: Marco Crivellari Cc: linux-kernel@vger.kernel.org, Lai Jiangshan , Frederic Weisbecker , Sebastian Andrzej Siewior , Michal Hocko , Breno Leitao Subject: Re: [PATCH v4 0/2] workqueue: Make WQ_UNBOUND the default behavior In-Reply-To: <20261015140148.231126-1-marco.crivellari@suse.com> References: <20261015140148.231126-1-marco.crivellari@suse.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hello, Marco. The following is a Claude-generated review. On Thu, Oct 15, 2026 at 04:01:46PM +0200, Marco Crivellari wrote: > Currently alloc_workqueue() make sure one among WQ_UNBOUND or WQ_PERCPU is > present. This is enforced warning and setting WQ_PERCPU as default when > alloc_workqueue() without WQ_PERCPU or WQ_UNBOUND. - 1/2: The description gives the future removal of WQ_UNBOUND as the only reason. Can it lead with why unbound should be the default, as dadb3ebcf395 ("workqueue: WQ_PERCPU added to alloc_workqueue users") does? Moving the defaulting above the wq_size computation is the one subtle point. Maybe add a sentence on it to the description? The new comment says WQ_UNBOUND is final at that point, but the WQ_POWER_EFFICIENT block right below can still set it. The first two paragraphs restate the if/else. Maybe trim it to the ordering constraint against wq_size? unlikely() on the neither-flag branch now marks the path that's meant to become the default. Maybe drop it? The WQ_POWER_EFFICIENT comment in include/linux/workqueue.h says such workqueues are per-cpu by default. With this patch, one without WQ_PERCPU is unbound regardless of workqueue.power_efficient. All in-tree users pass WQ_PERCPU, so only the text needs updating. Typos: "achive", "alloc_users()" (alloc_workqueue() users), "ensure" -> "ensures", "neither flags are" -> "neither flag is". - 2/2: The description says WQ_PERCPU is set for WQ_BH "regardless of what the caller passes", but WQ_BH | WQ_UNBOUND is rejected by the __WQ_BH_ALLOWS check. "the only permitted flags" dropped "additional", but WQ_BH itself is in __WQ_BH_ALLOWS too. Also, "workqueueus" typo. The new WQ_UNBOUND sentence sits after the "useful for the following cases" bullets and reads as one more case. Maybe move it to the top of the entry? Also, "Workqueue without" -> "Workqueues without". The Guidelines section still says "using a bound wq is usually beneficial", which now contradicts the default. Can that be updated too? Nit: doc patches in this tree usually use the "workqueue: doc:" prefix. Thanks. -- tejun