From: Srikar Dronamraju <srikar@linux.ibm.com>
To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
Peter Zijlstra <peterz@infradead.org>
Cc: Ben Segall <bsegall@google.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Ingo Molnar <mingo@kernel.org>,
Juri Lelli <juri.lelli@redhat.com>,
K Prateek Nayak <kprateek.nayak@amd.com>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Mel Gorman <mgorman@suse.de>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Shrikanth Hegde <sshegde@linux.ibm.com>,
Srikar Dronamraju <srikar@linux.ibm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Swapnil Sapkal <swapnil.sapkal@amd.com>,
Thomas Huth <thuth@redhat.com>,
Valentin Schneider <vschneid@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
virtualization@lists.linux.dev,
Yicong Yang <yangyicong@hisilicon.com>,
Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH 15/17] pseries/hotplug: Update available_cores on a dlpar event
Date: Thu, 4 Dec 2025 23:24:03 +0530 [thread overview]
Message-ID: <20251204175405.1511340-16-srikar@linux.ibm.com> (raw)
In-Reply-To: <20251204175405.1511340-1-srikar@linux.ibm.com>
Everytime, a DLPAR CPU event happens on a shared LPAR, the number of
entitled_cores, and virtual processors allotted to the LPAR can change.
Hence available_cores has to be updated to be in sync.
Signed-off-by: Srikar Dronamraju <srikar@linux.ibm.com>
---
arch/powerpc/platforms/pseries/hotplug-cpu.c | 6 ++++++
arch/powerpc/platforms/pseries/pseries.h | 1 +
arch/powerpc/platforms/pseries/smp.c | 2 +-
3 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index bc6926dbf148..4ba8cc049b5b 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -284,6 +284,9 @@ static int pseries_add_processor(struct device_node *np)
out:
cpu_maps_update_done();
+#ifdef CONFIG_PPC_SPLPAR
+ pseries_num_available_cores();
+#endif
free_cpumask_var(cpu_mask);
return rc;
}
@@ -323,6 +326,9 @@ static void pseries_remove_processor(struct device_node *np)
"with physical id 0x%x\n", thread);
}
cpu_maps_update_done();
+#ifdef CONFIG_PPC_SPLPAR
+ pseries_num_available_cores();
+#endif
}
static int dlpar_offline_cpu(struct device_node *dn)
diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h
index 2527c2049e74..1eed08752a03 100644
--- a/arch/powerpc/platforms/pseries/pseries.h
+++ b/arch/powerpc/platforms/pseries/pseries.h
@@ -121,6 +121,7 @@ extern u32 pseries_security_flavor;
void pseries_setup_security_mitigations(void);
#ifdef CONFIG_PPC_SPLPAR
void trigger_softoffline(unsigned long steal_ratio);
+unsigned int pseries_num_available_cores(void);
#endif
#ifdef CONFIG_PPC_64S_HASH_MMU
diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
index 69e209880b6f..a3daac4c3e1e 100644
--- a/arch/powerpc/platforms/pseries/smp.c
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -293,7 +293,7 @@ static unsigned int entitled_cores __read_mostly;
static unsigned int available_cores;
/* Get pseries soft entitlement limit */
-static unsigned int pseries_num_available_cores(void)
+unsigned int pseries_num_available_cores(void)
{
unsigned int present_cores = num_present_cpus() / threads_per_core;
unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
--
2.43.7
next prev parent reply other threads:[~2025-12-04 17:56 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-04 17:53 [PATCH 00/17] Steal time based dynamic CPU resource management Srikar Dronamraju
2025-12-04 17:53 ` [PATCH 01/17] sched/fair: Enable group_asym_packing in find_idlest_group Srikar Dronamraju
2025-12-04 17:53 ` [PATCH 02/17] powerpc/lpar: Reorder steal accounting calculation Srikar Dronamraju
2025-12-04 17:53 ` [PATCH 03/17] pseries/lpar: Process steal metrics Srikar Dronamraju
2025-12-04 17:53 ` [PATCH 04/17] powerpc/smp: Add num_available_cores callback for smp_ops Srikar Dronamraju
2025-12-04 17:53 ` [PATCH 05/17] pseries/smp: Query and set entitlements Srikar Dronamraju
2025-12-04 17:53 ` [PATCH 06/17] powerpc/smp: Delay processing steal time at boot Srikar Dronamraju
2025-12-04 17:53 ` [PATCH 07/17] sched/core: Set balance_callback only if CPU is dying Srikar Dronamraju
2025-12-04 17:53 ` [PATCH 08/17] sched/core: Implement CPU soft offline/online Srikar Dronamraju
2025-12-05 16:03 ` Peter Zijlstra
2025-12-05 18:54 ` Srikar Dronamraju
2025-12-05 16:07 ` Peter Zijlstra
2025-12-05 18:57 ` Srikar Dronamraju
2025-12-04 17:53 ` [PATCH 09/17] powerpc/smp: Implement arch_scale_cpu_capacity for shared LPARs Srikar Dronamraju
2025-12-04 17:53 ` [PATCH 10/17] powerpc/smp: Define arch_update_cpu_topology " Srikar Dronamraju
2025-12-04 17:53 ` [PATCH 11/17] pseries/smp: Create soft offline infrastructure for Powerpc " Srikar Dronamraju
2025-12-04 17:54 ` [PATCH 12/17] pseries/smp: Trigger softoffline based on steal metrics Srikar Dronamraju
2025-12-04 17:54 ` [PATCH 13/17] pseries/smp: Account cores when triggering softoffline Srikar Dronamraju
2025-12-04 17:54 ` [PATCH 14/17] powerpc/smp: Assume preempt if CPU is inactive Srikar Dronamraju
2025-12-04 17:54 ` Srikar Dronamraju [this message]
2025-12-04 17:54 ` [PATCH 16/17] pseries/smp: Allow users to override steal thresholds Srikar Dronamraju
2025-12-04 17:54 ` [PATCH 17/17] pseries/lpar: Add debug interface to set steal interval Srikar Dronamraju
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