From: David Hildenbrand <david@redhat.com>
To: James Morse <james.morse@arm.com>,
x86@kernel.org, linux-kernel@vger.kernel.org
Cc: Fenghua Yu <fenghua.yu@intel.com>,
Reinette Chatre <reinette.chatre@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
H Peter Anvin <hpa@zytor.com>, Babu Moger <Babu.Moger@amd.com>,
shameerali.kolothum.thodi@huawei.com,
D Scott Phillips OS <scott@os.amperecomputing.com>,
carl@os.amperecomputing.com, lcherian@marvell.com,
bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com,
baolin.wang@linux.alibaba.com,
Jamie Iles <quic_jiles@quicinc.com>,
Xin Hao <xhao@linux.alibaba.com>,
peternewman@google.com, dfustini@baylibre.com,
amitsinght@marvell.com
Subject: Re: [PATCH v9 09/24] x86/resctrl: Use __set_bit()/__clear_bit() instead of open coding
Date: Tue, 20 Feb 2024 17:00:46 +0100 [thread overview]
Message-ID: <b5bc883a-8a8a-4f07-a6ff-b1bd02ffc99d@redhat.com> (raw)
In-Reply-To: <20240213184438.16675-10-james.morse@arm.com>
On 13.02.24 19:44, James Morse wrote:
> 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 <james.morse@arm.com>
> Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
> Tested-by: Peter Newman <peternewman@google.com>
> Tested-by: Babu Moger <babu.moger@amd.com>
> Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
> Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
> Reviewed-by: Babu Moger <babu.moger@amd.com>
> ---
> 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/resctrl/rdtgroup.c
> index dcffd1c4a476..bc6e0f83c847 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 more
> * limited as the number of resources grows.
> */
That comment talks about "free CLOSIDs in a single integer". Once could
think about rephrasing that to "free CLOSIDs in a simple bitmap."
> -static int closid_free_map;
> +static unsigned long closid_free_map;
> static int closid_free_map_len;
>
> int closids_supported(void)
> @@ -130,8 +130,8 @@ static void closid_init(void)
>
> closid_free_map = BIT_MASK(rdt_min_closid) - 1;
Now that we use "unsigned long", I was wondering for a second if we
should use "proper" bitmap functions here like
bitmap_fill(closid_free_map, rdt_min_closid);
and converting the alloc path (replace ffs() in closid_alloc()):
closid = find_first_bit(closid_free_map, closid_free_map_len);
if (closid == closid_free_map_len)
return -ENOSPC;
__clear_bit(closid, &closid_free_map);
(would get rid of the closid-- in closid_alloc())
Just a thought, so
Reviewed-by: David Hildenbrand <david@redhat.com>
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2024-02-20 16:00 UTC|newest]
Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-13 18:44 [PATCH v9 00/24] x86/resctrl: monitored closid+rmid together, separate arch/fs locking James Morse
2024-02-13 18:44 ` [PATCH v9 01/24] tick/nohz: Move tick_nohz_full_mask declaration outside the #ifdef James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 02/24] x86/resctrl: kfree() rmid_ptrs from resctrl_exit() James Morse
2024-02-13 23:14 ` Reinette Chatre
2024-02-19 16:53 ` James Morse
2024-02-19 18:37 ` [tip: x86/cache] x86/resctrl: Free " tip-bot2 for James Morse
2024-02-20 15:27 ` [PATCH v9 02/24] x86/resctrl: kfree() " David Hildenbrand
2024-02-20 15:46 ` James Morse
2024-02-20 15:54 ` Thomas Gleixner
2024-02-20 16:01 ` James Morse
2024-02-20 16:12 ` Thomas Gleixner
2024-02-13 18:44 ` [PATCH v9 03/24] x86/resctrl: Create helper for RMID allocation and mondata dir creation James Morse
2024-02-19 15:49 ` David Hildenbrand
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 04/24] x86/resctrl: Move rmid allocation out of mkdir_rdt_prepare() James Morse
2024-02-19 18:37 ` [tip: x86/cache] x86/resctrl: Move RMID " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 05/24] x86/resctrl: Track the closid with the rmid James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 06/24] x86/resctrl: Access per-rmid structures by index James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 07/24] x86/resctrl: Allow RMID allocation to be scoped by CLOSID James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 08/24] x86/resctrl: Track the number of dirty RMID a CLOSID has James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 09/24] x86/resctrl: Use __set_bit()/__clear_bit() instead of open coding James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-20 16:00 ` David Hildenbrand [this message]
2024-02-20 16:27 ` [PATCH v9 09/24] " James Morse
2024-02-20 16:44 ` David Hildenbrand
2024-02-13 18:44 ` [PATCH v9 10/24] x86/resctrl: Allocate the cleanest CLOSID by searching closid_num_dirty_rmid James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 11/24] x86/resctrl: Move CLOSID/RMID matching and setting to use helpers James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 12/24] x86/resctrl: Add cpumask_any_housekeeping() for limbo/overflow James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 13/24] x86/resctrl: Queue mon_event_read() instead of sending an IPI James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 14/24] x86/resctrl: Allow resctrl_arch_rmid_read() to sleep James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 15/24] x86/resctrl: Allow arch to allocate memory needed in resctrl_arch_rmid_read() James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 16/24] x86/resctrl: Make resctrl_mounted checks explicit James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 17/24] x86/resctrl: Move alloc/mon static keys into helpers James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 18/24] x86/resctrl: Make rdt_enable_key the arch's decision to switch James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 19/24] x86/resctrl: Add helpers for system wide mon/alloc capable James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 20/24] x86/resctrl: Add CPU online callback for resctrl work James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 21/24] x86/resctrl: Allow overflow/limbo handlers to be scheduled on any-but cpu James Morse
2024-02-19 18:37 ` [tip: x86/cache] x86/resctrl: Allow overflow/limbo handlers to be scheduled on any-but CPU tip-bot2 for James Morse
2024-03-25 23:14 ` [PATCH v9 21/24] x86/resctrl: Allow overflow/limbo handlers to be scheduled on any-but cpu Tony Luck
2024-02-13 18:44 ` [PATCH v9 22/24] x86/resctrl: Add CPU offline callback for resctrl work James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 23/24] x86/resctrl: Move domain helper migration into resctrl_offline_cpu() James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 18:44 ` [PATCH v9 24/24] x86/resctrl: Separate arch and fs resctrl locks James Morse
2024-02-19 18:37 ` [tip: x86/cache] " tip-bot2 for James Morse
2024-02-13 23:26 ` [PATCH v9 00/24] x86/resctrl: monitored closid+rmid together, separate arch/fs locking Reinette Chatre
2024-02-14 15:01 ` Moger, Babu
2024-02-19 16:53 ` James Morse
2024-02-17 0:28 ` Tony Luck
2024-02-20 18:18 ` Reinette Chatre
2024-02-20 18:48 ` Luck, Tony
2024-02-17 10:55 ` Borislav Petkov
2024-02-19 16:49 ` Thomas Gleixner
2024-02-19 16:53 ` James Morse
2024-02-19 17:51 ` Borislav Petkov
2024-02-19 17:55 ` James Morse
2024-02-20 20:59 ` Tony Luck
2024-02-20 22:58 ` Reinette Chatre
2024-02-20 23:25 ` Luck, Tony
2024-02-21 0:34 ` [PATCH] x86/resctrl: Fix WARN in get_domain_from_cpu() Tony Luck
2024-02-21 5:10 ` Reinette Chatre
2024-02-21 12:06 ` James Morse
2024-02-21 19:31 ` [PATCH v2] " Tony Luck
2024-02-21 22:59 ` Reinette Chatre
2024-02-21 23:56 ` Tony Luck
2024-02-22 18:50 ` [PATCH v3 0/2] x86/resctrl: Pass domain to target CPU Tony Luck
2024-02-22 18:50 ` [PATCH v3 1/2] " Tony Luck
2024-02-27 22:05 ` Reinette Chatre
2024-02-22 18:50 ` [PATCH v3 2/2] x86/resctrl: Simply call convention for MSR update functions Tony Luck
2024-02-27 22:05 ` Reinette Chatre
2024-02-22 23:18 ` [PATCH v3 0/2] x86/resctrl: Pass domain to target CPU Reinette Chatre
2024-02-22 23:26 ` Luck, Tony
2024-03-08 21:38 ` [PATCH v5 " Tony Luck
2024-03-08 21:38 ` [PATCH v5 1/2] " Tony Luck
2024-03-12 20:06 ` Moger, Babu
2024-03-12 20:08 ` Luck, Tony
2024-04-24 12:01 ` [tip: x86/cache] " tip-bot2 for Tony Luck
2024-03-08 21:38 ` [PATCH v5 2/2] x86/resctrl: Simplify call convention for MSR update functions Tony Luck
2024-03-12 20:06 ` Moger, Babu
2024-04-24 12:01 ` [tip: x86/cache] " tip-bot2 for Tony Luck
2024-03-08 23:08 ` [PATCH v5 0/2] x86/resctrl: Pass domain to target CPU Reinette Chatre
2024-03-08 23:26 ` Luck, Tony
2024-03-29 4:55 ` Reinette Chatre
2024-02-21 12:06 ` [PATCH v9 00/24] x86/resctrl: monitored closid+rmid together, separate arch/fs locking James Morse
2024-02-21 16:48 ` Reinette Chatre
2024-02-21 17:30 ` Luck, Tony
2024-02-22 15:26 ` [tip: x86/cache] x86/resctrl: Remove lockdep annotation that triggers false positive tip-bot2 for James Morse
2024-02-19 16:54 ` [PATCH v9 00/24] x86/resctrl: monitored closid+rmid together, separate arch/fs locking James Morse
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