From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793907325; b=5VAI1hcISwYQSn0xhd2GKmwAXu9xUBkziybgPXCo7a7VW4LK/K111R7BAjdL9Gtx9oea 5XoypDMp5i6paEDreWaWiw1uqaFGUhG280dyPP/BiqrjK9+CrAu4FugWajWBnZt+Plm56 MY+Fl0lkdyRFsFRAm6C1zyc2AGZdR9CIebK1GDWrzdWyvGea2YFuMpz7E3C20SOFT6TKO yXZKsXDmSnisPCOMrm04Y+02PY/iwmTaps3KwOH5jJAlLKwklhK4n25bJe006s6g3FQp0 Rn4wcGf7vb4emECkAwowIpteTS/KlieeI+E0HU9iG+SC+e0Q+uoVgqhGN5aB3ZpmXlQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793907325; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=KYpEmlst2RMAqFXyOGI9xQrnSxV142QmlHBMWmUsiz8=; b=XorDyrPkinKzoes+AFyv17APeLwCCGG+8jnzurMK9Wnt+z2CPRQ1i3rSZWq2dLV+CCz2 Q2b0OMRM9seqqX/Phvxj8gmYOMQEo8cVtw9ek4vxNfmuVoVvietm13CCDjt7+Qcr1Pt7K YMXGall62Og5IBJf/uFnBWyMuxxKtLU92C9jLdJuF8BnyukrmTpmikEhdivRtbgX0tvV1 RqoMUTbRrc2TOlvDFvuHcDtaavev79A4jq4dReA5e0tnuZLGEIaf8F0dbWC8QzFNH+Qa3 MTLoPz6CCpaXjeWWueyTj2eDwdKHLWRxj9BY61+5MZS0jGLMyHsaZ+2gueDOCAH539A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=D7HKWZpd; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 095796077B4F; Thu, 5 Nov 2026 19:35:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=D7HKWZpd Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1833B1F0089E; Thu, 5 Nov 2026 19:35:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793907324; bh=KYpEmlst2RMAqFXyOGI9xQrnSxV142QmlHBMWmUsiz8=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=D7HKWZpdJlBXoSwsMjTjzNPkVew6KHrh4fawwQ2ulEULxhqG9XivG3Fp1ISuAwQMs Hbq/80xvcy5mK2zclNAv5UeDsWP9xoAeq/jUyUIkH4aln+AG0f8NlrzzD8Lp/NDA2z asdv9M90m9ShsSX4Ou/gTVHerHVAH3lLWi5CocYCqRvM/6bWUqB04QX6LVAK7e1GKK UzVX0OSOF7WsaBpjey4MAjogWboVvhDsYVxoh9AXfTdllPpwKgRpIWe53zpJYPr6YQ eHh6pR2ZAvzxF2Dj6TA9K/8Ca7BrjKlLNX6M0uWnkQFqgU9vYgoQJLLUshku7SS+Fn EUH1IEGMOTXBA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH RESEND v2 05/23] proc: keep the open files of an entry in an open node Reply-To: sashiko-reviews@lists.linux.dev To: "Christian Brauner" Cc: "Linus Torvalds" , "Jann Horn" , "Josef Bacik" , "Chris Mason" , "Jeff Layton" , NeilBrown , "Eric Dumazet" , "Thomas Gleixner" , "Al Viro" , "Jonathan Corbet" , "Christoph Hellwig" , "Greg Kroah-Hartman" , "Joel Granados" , "Kees Cook" , "Jan Kara" , "Jan Kara" , linux-s390@vger.kernel.org, coreteam@netfilter.org, kexec@lists.infradead.org, linux-pci@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-usb@vger.kernel.org, samba-technical@lists.samba.org, linux-m68k@lists.linux-m68k.org, linux-serial@vger.kernel.org, "Takashi Iwai" , linux-ext4@vger.kernel.org, "Chuck Lever" , tytso@mit.edu, "Heiko Carstens" , "Vasily Gorbik" , "Alexander Gordeev" , "Christian Borntraeger" In-Reply-To: <20261104-work-procfs-core-v2-5-76ace653a773@kernel.org> References: <20261104-work-procfs-core-v2-0-76ace653a773@kernel.org> <20261104-work-procfs-core-v2-5-76ace653a773@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 05 Nov 2026 19:35:22 +0000 X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > procfs remembers the open files of an entry that has a ->proc_release(), > so that it can call the release hook when the entry is removed while > files are still open. The list head for that and the lock that protects > it sit in every struct proc_dir_entry, for the few entries that need > them, and the next patches want to keep more there, the vm_operations > of an entry's mappings for a start. >=20 > Move the list into a struct pde_open_node that only those entries get. > It is allocated when the entry is registered, whether an entry needs > one follows from its proc_ops, and freed with the entry. So ->open is > constant for the life of an entry, nothing has to look it up or pin it, > and the removal path stays what it is. kernfs allocates its > kernfs_open_node on the first open instead, but there every attribute > can be polled and so every one of them would need one. In procfs the > entries that need the node are the exception. Permanent entries don't > get one, they are never removed, so their release hook only ever runs > when a file is closed. >=20 > The spinlock stays in the entry and now protects what hangs off ->open. > Moving it behind the gid fills a hole, so struct proc_dir_entry shrinks > from 160 to 144 bytes on x86_64 here, and it ends up at 160 bytes at > the end of this series instead of the 184 it would have grown to with > the read and write limits and the vm_operations of its mappings in it. > That keeps 32 bytes of inline name instead of 8. 34 of the 68 /proc/net > names a network namespace gets are longer than 7 characters. >=20 > No functional changes. >=20 > Signed-off-by: Christian Brauner (Amutable) Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261104-work-procf= s-core-v2-0-76ace653a773@kernel.org?part=3D5