From nobody Sat Dec 27 20:55:29 2025 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A00F147F71 for ; Fri, 15 Dec 2023 17:44:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3D7A4C15; Fri, 15 Dec 2023 09:45:15 -0800 (PST) Received: from merodach.members.linode.com (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4D9783F5A1; Fri, 15 Dec 2023 09:44:27 -0800 (PST) From: James Morse To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: Fenghua Yu , Reinette Chatre , Thomas Gleixner , Ingo Molnar , Borislav Petkov , H Peter Anvin , Babu Moger , James Morse , shameerali.kolothum.thodi@huawei.com, D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, Babu Moger Subject: [PATCH v8 09/24] x86/resctrl: Use __set_bit()/__clear_bit() instead of open coding Date: Fri, 15 Dec 2023 17:43:28 +0000 Message-Id: <20231215174343.13872-10-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20231215174343.13872-1-james.morse@arm.com> References: <20231215174343.13872-1-james.morse@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The resctrl CLOSID allocator uses a single 32bit word to track which CLOSID are free. The setting and clearing of bits is open coded. Convert the existing open coded bit manipulations of closid_free_map to use __set_bit() and friends. These don't need to be atomic as this list is protected by the mutex. Signed-off-by: James Morse Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Babu Moger Reviewed-by: Shaopeng Tan Reviewed-by: Reinette Chatre Reviewed-by: Babu Moger --- Changes since v6: * Use the __ inatomic helpers and add lockdep_assert_held() annotations to document how this is safe. * Fixed a resctrl_closid_is_free()/closid_allocated() rename in the commit message. * Use RESCTRL_RESERVED_CLOSID to improve readability. Changes since v7: * Removed paragraph explaining why this should be done now due to badword 'subsequent'. * Changed a comment to refer to RESCTRL_RESERVED_CLOSID. --- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/r= esctrl/rdtgroup.c index 12a557c96100..f6b52415ca3d 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -111,7 +111,7 @@ void rdt_staged_configs_clear(void) * - Our choices on how to configure each resource become progressively mo= re * limited as the number of resources grows. */ -static int closid_free_map; +static unsigned long closid_free_map; static int closid_free_map_len; =20 int closids_supported(void) @@ -130,8 +130,8 @@ static void closid_init(void) =20 closid_free_map =3D BIT_MASK(rdt_min_closid) - 1; =20 - /* CLOSID 0 is always reserved for the default group */ - closid_free_map &=3D ~1; + /* RESCTRL_RESERVED_CLOSID is always reserved for the default group */ + __clear_bit(RESCTRL_RESERVED_CLOSID, &closid_free_map); closid_free_map_len =3D rdt_min_closid; } =20 @@ -139,17 +139,21 @@ static int closid_alloc(void) { u32 closid =3D ffs(closid_free_map); =20 + lockdep_assert_held(&rdtgroup_mutex); + if (closid =3D=3D 0) return -ENOSPC; closid--; - closid_free_map &=3D ~(1 << closid); + __clear_bit(closid, &closid_free_map); =20 return closid; } =20 void closid_free(int closid) { - closid_free_map |=3D 1 << closid; + lockdep_assert_held(&rdtgroup_mutex); + + __set_bit(closid, &closid_free_map); } =20 /** @@ -161,7 +165,9 @@ void closid_free(int closid) */ static bool closid_allocated(unsigned int closid) { - return (closid_free_map & (1 << closid)) =3D=3D 0; + lockdep_assert_held(&rdtgroup_mutex); + + return !test_bit(closid, &closid_free_map); } =20 /** --=20 2.20.1