From: James Morse <james.morse@arm.com>
To: 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>,
James Morse <james.morse@arm.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, Babu Moger <babu.moger@amd.com>
Subject: [PATCH v8 10/24] x86/resctrl: Allocate the cleanest CLOSID by searching closid_num_dirty_rmid
Date: Fri, 15 Dec 2023 17:43:29 +0000 [thread overview]
Message-ID: <20231215174343.13872-11-james.morse@arm.com> (raw)
In-Reply-To: <20231215174343.13872-1-james.morse@arm.com>
MPAM's PMG bits extend its PARTID space, meaning the same PMG value can be
used for different control groups.
This means once a CLOSID is allocated, all its monitoring ids may still be
dirty, and held in limbo.
Instead of allocating the first free CLOSID, on architectures where
CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID is enabled, search
closid_num_dirty_rmid[] to find the cleanest CLOSID.
The CLOSID found is returned to closid_alloc() for the free list
to be updated.
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>
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 v4:
* Dropped stale section from comment
Changes since v5:
* Renamed some variables.
Changes since v7:
* Made comments over closid_num_dirty_rmid() not a kdoc comment.
---
arch/x86/kernel/cpu/resctrl/internal.h | 2 ++
arch/x86/kernel/cpu/resctrl/monitor.c | 47 +++++++++++++++++++++++++-
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 19 ++++++++---
3 files changed, 62 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 2f1d4f141dab..521afa016b05 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -568,5 +568,7 @@ void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
void __init thread_throttle_mode_init(void);
void __init mbm_config_rftype_init(const char *config);
void rdt_staged_configs_clear(void);
+bool closid_allocated(unsigned int closid);
+int resctrl_find_cleanest_closid(void);
#endif /* _ASM_X86_RESCTRL_INTERNAL_H */
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 6dfc68c800c8..fdbef88ff39b 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -50,7 +50,7 @@ struct rmid_entry {
*/
static LIST_HEAD(rmid_free_lru);
-/**
+/*
* @closid_num_dirty_rmid The number of dirty RMID each CLOSID has.
* Only allocated when CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID is defined.
* Indexed by CLOSID. Protected by rdtgroup_mutex.
@@ -386,6 +386,51 @@ static struct rmid_entry *resctrl_find_free_rmid(u32 closid)
return ERR_PTR(-ENOSPC);
}
+/**
+ * resctrl_find_cleanest_closid() - Find a CLOSID where all the associated
+ * RMID are clean, or the CLOSID that has
+ * the most clean RMID.
+ *
+ * MPAM's equivalent of RMID are per-CLOSID, meaning a freshly allocated CLOSID
+ * may not be able to allocate clean RMID. To avoid this the allocator will
+ * choose the CLOSID with the most clean RMID.
+ *
+ * When the CLOSID and RMID are independent numbers, the first free CLOSID will
+ * be returned.
+ */
+int resctrl_find_cleanest_closid(void)
+{
+ u32 cleanest_closid = ~0;
+ int i = 0;
+
+ lockdep_assert_held(&rdtgroup_mutex);
+
+ if (!IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID))
+ return -EIO;
+
+ for (i = 0; i < closids_supported(); i++) {
+ int num_dirty;
+
+ if (closid_allocated(i))
+ continue;
+
+ num_dirty = closid_num_dirty_rmid[i];
+ if (num_dirty == 0)
+ return i;
+
+ if (cleanest_closid == ~0)
+ cleanest_closid = i;
+
+ if (num_dirty < closid_num_dirty_rmid[cleanest_closid])
+ cleanest_closid = i;
+ }
+
+ if (cleanest_closid == ~0)
+ return -ENOSPC;
+
+ return cleanest_closid;
+}
+
/*
* For MPAM the RMID value is not unique, and has to be considered with
* the CLOSID. The (CLOSID, RMID) pair is allocated on all domains, which
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index f6b52415ca3d..00f830f729b3 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -137,13 +137,22 @@ static void closid_init(void)
static int closid_alloc(void)
{
- u32 closid = ffs(closid_free_map);
+ int cleanest_closid;
+ u32 closid;
lockdep_assert_held(&rdtgroup_mutex);
- if (closid == 0)
- return -ENOSPC;
- closid--;
+ if (IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID)) {
+ cleanest_closid = resctrl_find_cleanest_closid();
+ if (cleanest_closid < 0)
+ return cleanest_closid;
+ closid = cleanest_closid;
+ } else {
+ closid = ffs(closid_free_map);
+ if (closid == 0)
+ return -ENOSPC;
+ closid--;
+ }
__clear_bit(closid, &closid_free_map);
return closid;
@@ -163,7 +172,7 @@ void closid_free(int closid)
* Return: true if @closid is currently associated with a resource group,
* false if @closid is free
*/
-static bool closid_allocated(unsigned int closid)
+bool closid_allocated(unsigned int closid)
{
lockdep_assert_held(&rdtgroup_mutex);
--
2.20.1
next prev parent reply other threads:[~2023-12-15 17:44 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-15 17:43 [PATCH v8 00/24] x86/resctrl: monitored closid+rmid together, separate arch/fs locking James Morse
2023-12-15 17:43 ` [PATCH v8 01/24] tick/nohz: Move tick_nohz_full_mask declaration outside the #ifdef James Morse
2023-12-15 20:31 ` Thomas Gleixner
2024-01-22 18:05 ` James Morse
2023-12-15 17:43 ` [PATCH v8 02/24] x86/resctrl: kfree() rmid_ptrs from resctrl_exit() James Morse
2023-12-16 4:57 ` Reinette Chatre
2023-12-15 17:43 ` [PATCH v8 03/24] x86/resctrl: Create helper for RMID allocation and mondata dir creation James Morse
2023-12-15 17:43 ` [PATCH v8 04/24] x86/resctrl: Move rmid allocation out of mkdir_rdt_prepare() James Morse
2023-12-15 17:43 ` [PATCH v8 05/24] x86/resctrl: Track the closid with the rmid James Morse
2023-12-16 4:58 ` Reinette Chatre
2024-01-22 18:05 ` James Morse
2023-12-15 17:43 ` [PATCH v8 06/24] x86/resctrl: Access per-rmid structures by index James Morse
2023-12-16 4:58 ` Reinette Chatre
2024-01-22 18:05 ` James Morse
2023-12-15 17:43 ` [PATCH v8 07/24] x86/resctrl: Allow RMID allocation to be scoped by CLOSID James Morse
2023-12-15 17:43 ` [PATCH v8 08/24] x86/resctrl: Track the number of dirty RMID a CLOSID has James Morse
2024-01-03 19:43 ` Moger, Babu
2024-01-22 18:05 ` James Morse
2024-01-04 19:13 ` Peter Newman
2024-01-22 18:05 ` James Morse
2023-12-15 17:43 ` [PATCH v8 09/24] x86/resctrl: Use __set_bit()/__clear_bit() instead of open coding James Morse
2023-12-15 17:43 ` James Morse [this message]
2023-12-16 5:01 ` [PATCH v8 10/24] x86/resctrl: Allocate the cleanest CLOSID by searching closid_num_dirty_rmid Reinette Chatre
2024-01-22 18:06 ` James Morse
2023-12-15 17:43 ` [PATCH v8 11/24] x86/resctrl: Move CLOSID/RMID matching and setting to use helpers James Morse
2023-12-15 17:43 ` [PATCH v8 12/24] x86/resctrl: Add cpumask_any_housekeeping() for limbo/overflow James Morse
2023-12-15 17:43 ` [PATCH v8 13/24] x86/resctrl: Queue mon_event_read() instead of sending an IPI James Morse
2024-01-03 19:43 ` Moger, Babu
2024-01-22 18:06 ` James Morse
2023-12-15 17:43 ` [PATCH v8 14/24] x86/resctrl: Allow resctrl_arch_rmid_read() to sleep James Morse
2024-01-03 19:43 ` Moger, Babu
2024-01-22 18:06 ` James Morse
2023-12-15 17:43 ` [PATCH v8 15/24] x86/resctrl: Allow arch to allocate memory needed in resctrl_arch_rmid_read() James Morse
2023-12-15 17:43 ` [PATCH v8 16/24] x86/resctrl: Make resctrl_mounted checks explicit James Morse
2023-12-15 17:43 ` [PATCH v8 17/24] x86/resctrl: Move alloc/mon static keys into helpers James Morse
2023-12-15 17:43 ` [PATCH v8 18/24] x86/resctrl: Make rdt_enable_key the arch's decision to switch James Morse
2023-12-15 17:43 ` [PATCH v8 19/24] x86/resctrl: Add helpers for system wide mon/alloc capable James Morse
2024-01-03 19:43 ` Moger, Babu
2024-01-22 18:06 ` James Morse
2023-12-15 17:43 ` [PATCH v8 20/24] x86/resctrl: Add CPU online callback for resctrl work James Morse
2023-12-15 17:43 ` [PATCH v8 21/24] x86/resctrl: Allow overflow/limbo handlers to be scheduled on any-but cpu James Morse
2023-12-16 5:02 ` Reinette Chatre
2024-01-22 18:06 ` James Morse
2023-12-15 17:43 ` [PATCH v8 22/24] x86/resctrl: Add CPU offline callback for resctrl work James Morse
2023-12-15 17:43 ` [PATCH v8 23/24] x86/resctrl: Move domain helper migration into resctrl_offline_cpu() James Morse
2023-12-15 17:43 ` [PATCH v8 24/24] x86/resctrl: Separate arch and fs resctrl locks James Morse
2023-12-22 22:43 ` [PATCH v8 00/24] x86/resctrl: monitored closid+rmid together, separate arch/fs locking Carl Worth
2024-01-22 18:06 ` James Morse
2024-01-03 19:42 ` Moger, Babu
2024-01-22 18:06 ` James Morse
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