- Kernel - mailweb.openeuler.org

[PATCH OLK-6.6] sched/fair: Remove spurious shorter slice preemption
by Chen Jinghuang 11 Nov '26

11 Nov '26

From: Vincent Guittot <vincent.guittot(a)linaro.org> mainline inclusion from mainline-v6.17-rc1 commit 9de74a9850b9468ac2f515bfbe0844e0bfae869d category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/8903 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- Even if the waking task can preempt current, it might not be the one selected by pick_task_fair. Check that the waking task will be selected if we cancel the slice protection before doing so. Signed-off-by: Vincent Guittot <vincent.guittot(a)linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Link: https://lkml.kernel.org/r/20250708165630.1948751-4-vincent.guittot@linaro.o… Conflicts: kernel/sched/fair.c [a trival context conflict] Signed-off-by: Zhang Qiao <zhangqiao22(a)huawei.com> Signed-off-by: Chen Jinghuang <chenjinghuang2(a)huawei.com> --- kernel/sched/fair.c | 43 +++++++++++-------------------------------- 1 file changed, 11 insertions(+), 32 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 69176c7134bb..9b2bfa623a49 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1250,7 +1250,7 @@ static inline void cancel_protect_slice(struct sched_entity *se) * * Which allows tree pruning through eligibility. */ -static struct sched_entity *pick_eevdf(struct cfs_rq *cfs_rq, bool wakeup_preempt) +static struct sched_entity *__pick_eevdf(struct cfs_rq *cfs_rq, bool protect) { struct rb_node *node = cfs_rq->tasks_timeline.rb_root.rb_node; struct sched_entity *se = __pick_first_entity(cfs_rq); @@ -1279,11 +1279,11 @@ static struct sched_entity *pick_eevdf(struct cfs_rq *cfs_rq, bool wakeup_preemp * elapsed. */ if (curr && - !(sched_feat(RUN_TO_PARITY_WAKEUP) && wakeup_preempt && curr->vlag == curr->deadline) && + !(sched_feat(RUN_TO_PARITY_WAKEUP) && protect && protect_slice(curr)) && !entity_eligible(cfs_rq, curr)) curr = NULL; - if (curr && protect_slice(curr)) + if (curr && protect && protect_slice(curr)) return curr; /* Pick the leftmost entity if it's eligible */ @@ -1527,27 +1527,6 @@ static inline bool resched_next_slice(struct cfs_rq *cfs_rq, struct sched_entity return !entity_eligible(cfs_rq, curr); } -static inline bool do_preempt_short(struct cfs_rq *cfs_rq, - struct sched_entity *pse, struct sched_entity *se) -{ - if (!sched_feat(PREEMPT_SHORT)) - return false; - - if (pse->slice >= se->slice) - return false; - - if (!entity_eligible(cfs_rq, pse)) - return false; - - if (entity_before(pse, se)) - return true; - - if (!entity_eligible(cfs_rq, se)) - return true; - - return false; -} - /* * Used by other classes to account runtime. */ @@ -5930,7 +5909,7 @@ pick_next_entity(struct cfs_rq *cfs_rq) cfs_rq->next && entity_eligible(cfs_rq, cfs_rq->next)) return cfs_rq->next; - return pick_eevdf(cfs_rq, false); + return __pick_eevdf(cfs_rq, false); } static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq); @@ -9861,6 +9840,7 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int struct cfs_rq *cfs_rq = task_cfs_rq(curr); int next_buddy_marked = 0; int cse_is_idle, pse_is_idle; + bool do_preempt_short = false; bool ret = 0; if (unlikely(se == pse)) @@ -9916,7 +9896,7 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int * When non-idle entity preempt an idle entity, * don't give idle entity slice protection. */ - cancel_protect_slice(se); + do_preempt_short = true; goto preempt; } @@ -9939,22 +9919,21 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int /* * If @p has a shorter slice than current and @p is eligible, override * current's slice protection in order to allow preemption. - * - * Note that even if @p does not turn out to be the most eligible - * task at this moment, current's slice protection will be lost. */ - if (do_preempt_short(cfs_rq, pse, se)) - cancel_protect_slice(se); + do_preempt_short = sched_feat(PREEMPT_SHORT) && (pse->slice < se->slice); /* * If @p has become the most eligible task, force preemption. */ - if (pick_eevdf(cfs_rq, true) == pse) + if (__pick_eevdf(cfs_rq, !do_preempt_short) == pse) goto preempt; return; preempt: + if (do_preempt_short) + cancel_protect_slice(se); + resched_curr(rq); } -- 2.34.1

2 5

[PATCH OLK-6.6 V3 0/9] P2PDMA PATCHSET PART 1
by Zizhi Wo 09 Nov '26

09 Nov '26

To support iostat statistics of passthrough and support dm/md/nvme-multipath p2pdma. Bart Van Assche (1): block: Fix queue_iostats_passthrough_show() Chaitanya Kulkarni (1): block: clear BLK_FEAT_PCI_P2PDMA in blk_stack_limits() for non-supporting devices Keith Busch (3): block: enable passthrough command statistics block: export passthrough stats enabled nvme: add support multipath passthrough iostats Kiran Kumar Modukuri (2): md: propagate BLK_FEAT_PCI_P2PDMA from member devices to RAID device nvme-multipath: enable PCI P2PDMA for multipath devices Zizhi Wo (1): block: withhold P2PDMA from integrity-bearing stacks hotforest (1): dm: pass PCI P2PDMA through linear and striped targets Documentation/ABI/stable/sysfs-block | 8 ++++++ block/blk-mq-debugfs.c | 1 + block/blk-settings.c | 7 +++++ block/blk-sysfs.c | 26 ++++++++++++++++++ block/blk.h | 4 ++- drivers/md/dm-linear.c | 3 +- drivers/md/dm-stripe.c | 3 +- drivers/md/dm-table.c | 27 ++++++++++++++++++ drivers/md/raid0.c | 2 ++ drivers/md/raid1.c | 1 + drivers/md/raid10.c | 1 + drivers/nvme/host/core.c | 6 ++++ drivers/nvme/host/ioctl.c | 9 ++++++ drivers/nvme/host/multipath.c | 6 +++- include/linux/blk-mq.h | 41 ++++++++++++++++++++++++++++ include/linux/blkdev.h | 3 ++ include/linux/device-mapper.h | 5 ++++ 17 files changed, 149 insertions(+), 4 deletions(-) -- 2.52.0

2 10

[PATCH OLK-6.6 V2 0/9] P2PDMA PATCHSET PART 1
by Zizhi Wo 09 Nov '26

09 Nov '26

To support iostat statistics of passthrough and support dm/md/nvme-multipath p2pdma. Bart Van Assche (1): block: Fix queue_iostats_passthrough_show() Chaitanya Kulkarni (1): block: clear BLK_FEAT_PCI_P2PDMA in blk_stack_limits() for non-supporting devices Keith Busch (3): block: enable passthrough command statistics block: export passthrough stats enabled nvme: add support multipath passthrough iostats Kiran Kumar Modukuri (2): md: propagate BLK_FEAT_PCI_P2PDMA from member devices to RAID device nvme-multipath: enable PCI P2PDMA for multipath devices Zizhi Wo (1): block: withhold P2PDMA from integrity-bearing stacks hotforest (1): dm: pass PCI P2PDMA through linear and striped targets Documentation/ABI/stable/sysfs-block | 8 ++++++ block/blk-mq-debugfs.c | 1 + block/blk-settings.c | 20 ++++++++++++++ block/blk-sysfs.c | 26 ++++++++++++++++++ block/blk.h | 4 ++- drivers/md/dm-linear.c | 3 +- drivers/md/dm-stripe.c | 3 +- drivers/md/dm-table.c | 27 ++++++++++++++++++ drivers/md/raid0.c | 2 ++ drivers/md/raid1.c | 1 + drivers/md/raid10.c | 1 + drivers/nvme/host/core.c | 6 ++++ drivers/nvme/host/ioctl.c | 9 ++++++ drivers/nvme/host/multipath.c | 6 +++- include/linux/blk-mq.h | 41 ++++++++++++++++++++++++++++ include/linux/blkdev.h | 3 ++ include/linux/device-mapper.h | 5 ++++ 17 files changed, 162 insertions(+), 4 deletions(-) -- 2.52.0

2 10

[PATCH OLK-5.10 0/2] checkpatch.pl: minor improvements
by Tengda Wu 09 Nov '26

09 Nov '26

checkpatch.pl: minor improvements. Jeff Layton (1): checkpatch.pl: adapt to new Assisted-by: format Tengda Wu (1): checkpatch: recognize Co-authored-by as a valid signature tag scripts/checkpatch.pl | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) -- 2.34.1

2 3

[PATCH OLK-6.6 0/2] checkpatch.pl: minor improvements
by Tengda Wu 09 Nov '26

09 Nov '26

checkpatch.pl: minor improvements Jeff Layton (1): checkpatch.pl: adapt to new Assisted-by: format Tengda Wu (1): checkpatch: recognize Co-authored-by as a valid signature tag scripts/checkpatch.pl | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) -- 2.34.1

2 3

[PATCH OLK-5.10 0/2] checkpatch.pl: minor improvements
by Tengda Wu 09 Nov '26

09 Nov '26

checkpatch.pl: minor improvements. Jeff Layton (1): checkpatch.pl: adapt to new Assisted-by: format Tengda Wu (1): checkpatch: recognize Co-authored-by as a valid signature tag scripts/checkpatch.pl | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) -- 2.34.1

2 3

[PATCH OLK-6.6 0/2] checkpatch.pl: minor improvements
by Tengda Wu 09 Nov '26

09 Nov '26

checkpatch.pl: minor improvements Jeff Layton (1): checkpatch.pl: adapt to new Assisted-by: format Tengda Wu (1): checkpatch: recognize Co-authored-by as a valid signature tag scripts/checkpatch.pl | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) -- 2.34.1

2 3

[PATCH OLK-6.6 0/9] P2PDMA PATCHSET PART 1
by Zizhi Wo 09 Nov '26

09 Nov '26

To support iostat statistics of passthrough and support dm/md/nvme-multipath p2pdma. Bart Van Assche (1): block: Fix queue_iostats_passthrough_show() Chaitanya Kulkarni (1): block: clear BLK_FEAT_PCI_P2PDMA in blk_stack_limits() for non-supporting devices Keith Busch (3): block: enable passthrough command statistics block: export passthrough stats enabled nvme: add support multipath passthrough iostats Kiran Kumar Modukuri (2): md: propagate BLK_FEAT_PCI_P2PDMA from member devices to RAID device nvme-multipath: enable PCI P2PDMA for multipath devices Zizhi Wo (1): block: withhold P2PDMA from integrity-bearing stacks hotforest (1): dm: pass PCI P2PDMA through linear and striped targets Documentation/ABI/stable/sysfs-block | 8 ++++++ block/blk-mq-debugfs.c | 1 + block/blk-settings.c | 5 ++++ block/blk-sysfs.c | 26 ++++++++++++++++++ block/blk.h | 4 ++- drivers/md/dm-linear.c | 3 +- drivers/md/dm-stripe.c | 3 +- drivers/md/dm-table.c | 27 ++++++++++++++++++ drivers/md/raid0.c | 2 ++ drivers/md/raid1.c | 1 + drivers/md/raid10.c | 1 + drivers/nvme/host/core.c | 6 ++++ drivers/nvme/host/ioctl.c | 9 ++++++ drivers/nvme/host/multipath.c | 6 +++- include/linux/blk-mq.h | 41 ++++++++++++++++++++++++++++ include/linux/blkdev.h | 3 ++ include/linux/device-mapper.h | 5 ++++ 17 files changed, 147 insertions(+), 4 deletions(-) -- 2.52.0

2 10

[PATCH 0/9] P2PDMA PATCHSET PART 1
by Zizhi Wo 09 Nov '26

09 Nov '26

To support iostat statistics of passthrough and support dm/md/nvme-multipath p2pdma. Bart Van Assche (1): block: Fix queue_iostats_passthrough_show() Chaitanya Kulkarni (1): block: clear BLK_FEAT_PCI_P2PDMA in blk_stack_limits() for non-supporting devices Keith Busch (3): block: enable passthrough command statistics block: export passthrough stats enabled nvme: add support multipath passthrough iostats Kiran Kumar Modukuri (2): md: propagate BLK_FEAT_PCI_P2PDMA from member devices to RAID device nvme-multipath: enable PCI P2PDMA for multipath devices Zizhi Wo (1): block: withhold P2PDMA from integrity-bearing stacks hotforest (1): dm: pass PCI P2PDMA through linear and striped targets Documentation/ABI/stable/sysfs-block | 8 ++++++ block/blk-mq-debugfs.c | 1 + block/blk-settings.c | 5 ++++ block/blk-sysfs.c | 26 ++++++++++++++++++ block/blk.h | 4 ++- drivers/md/dm-linear.c | 3 +- drivers/md/dm-stripe.c | 3 +- drivers/md/dm-table.c | 27 ++++++++++++++++++ drivers/md/raid0.c | 2 ++ drivers/md/raid1.c | 1 + drivers/md/raid10.c | 1 + drivers/nvme/host/core.c | 6 ++++ drivers/nvme/host/ioctl.c | 9 ++++++ drivers/nvme/host/multipath.c | 6 +++- include/linux/blk-mq.h | 41 ++++++++++++++++++++++++++++ include/linux/blkdev.h | 3 ++ include/linux/device-mapper.h | 5 ++++ 17 files changed, 147 insertions(+), 4 deletions(-) -- 2.52.0

1 9

[PATCH OLK-6.6 1/2] KVM: arm64: Add runtime switch for TLBI DVMBM feature
by lishusen 09 Nov '26

09 Nov '26

From: lishusen <lishusen2(a)h-partners.com> Unify the two DVMBM control switches so that tlbi_dvmbm_enable is the single runtime switch, initialized from the cmdline parameter kvm-arm.dvmbm_enabled at KVM init time. With this change, kvm-arm.dvmbm_enabled=1 automatically sets tlbi_dvmbm_enable=1, and the DVMBM feature state is consistent with tlbi_dvmbm_enable (/sys/module/kvm/parameters/tlbi_dvmbm_enable). --- arch/arm64/kvm/arm.c | 12 +++++++++- arch/arm64/kvm/hisilicon/hisi_virt.c | 36 ++++++++++++++++++++++++---- arch/arm64/kvm/hisilicon/hisi_virt.h | 16 +++++++++++++ 3 files changed, 59 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 9319d1b72239..921a0a9150a1 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -105,6 +105,16 @@ static const struct kernel_param_ops force_wfi_trap_ops = { bool force_wfi_trap; module_param_cb(force_wfi_trap, &force_wfi_trap_ops, &force_wfi_trap, 0644); +static const struct kernel_param_ops tlbi_dvmbm_enable_ops = { + .set = dvmbm_enable_update, + .get = param_get_bool, +}; + +bool tlbi_dvmbm_enable = false; +MODULE_PARM_DESC(tlbi_dvmbm_enable, "bool"); +module_param_cb(tlbi_dvmbm_enable, &tlbi_dvmbm_enable_ops, &tlbi_dvmbm_enable, + 0644); + static int vcpu_req_reload_wfi_traps(const char *val, const struct kernel_param *kp) { struct kvm *kvm; @@ -3569,7 +3579,7 @@ static __init int kvm_arm_init(void) kvm_ncsnp_support = hisi_ncsnp_supported(); kvm_dvmbm_support = hisi_dvmbm_supported(); kvm_info("KVM ncsnp %s\n", kvm_ncsnp_support ? "enabled" : "disabled"); - kvm_info("KVM dvmbm %s\n", kvm_dvmbm_support ? "enabled" : "disabled"); + kvm_info("KVM dvmbm %s\n", kvm_dvmbm_enabled() ? "enabled" : "disabled"); if (kvm_dvmbm_support) kvm_get_pg_cfg(); diff --git a/arch/arm64/kvm/hisilicon/hisi_virt.c b/arch/arm64/kvm/hisilicon/hisi_virt.c index 0be4ebbc540d..e92661f201a4 100644 --- a/arch/arm64/kvm/hisilicon/hisi_virt.c +++ b/arch/arm64/kvm/hisilicon/hisi_virt.c @@ -146,7 +146,7 @@ static int __init early_dvmbm_enable(char *buf) } early_param("kvm-arm.dvmbm_enabled", early_dvmbm_enable); -static void hardware_enable_dvmbm(void) +static void hardware_enable_dvmbm(void *data) { u64 val; @@ -259,7 +259,9 @@ bool hisi_dvmbm_supported(void) /* reset */ on_each_cpu(hardware_disable_dvmbm, NULL, 1); - return dvmbm_enabled; + tlbi_dvmbm_enable = dvmbm_enabled; + + return true; } int kvm_sched_affinity_vcpu_init(struct kvm_vcpu *vcpu) @@ -558,7 +560,8 @@ void kvm_tlbi_dvmbm_vcpu_load(struct kvm_vcpu *vcpu) if (!kvm_dvmbm_support) return; - hardware_enable_dvmbm(); + if (kvm_dvmbm_enabled()) + hardware_enable_dvmbm(NULL); cpumask_copy(vcpu->arch.sched_cpus, current->cpus_ptr); if (likely(cpumask_equal(vcpu->arch.sched_cpus, @@ -609,7 +612,32 @@ void kvm_tlbi_dvmbm_vcpu_put(struct kvm_vcpu *vcpu) return; cpumask_copy(vcpu->arch.pre_sched_cpus, vcpu->arch.sched_cpus); - hardware_disable_dvmbm(NULL); + if (kvm_dvmbm_enabled()) + hardware_disable_dvmbm(NULL); +} + +int dvmbm_enable_update(const char *val, const struct kernel_param *kp) +{ + int err = param_set_bool(val, kp); + + if (err) + return err; + + if (!kvm_dvmbm_support) { + kvm_info("TLBI dvmbm not supported by this hardware. " + "Config ignored!\n"); + return err; + } + + if (kvm_dvmbm_enabled()) { + on_each_cpu(hardware_enable_dvmbm, NULL, 1); + kvm_info("KVM dvmbm enabled\n"); + } else { + on_each_cpu(hardware_disable_dvmbm, NULL, 1); + kvm_info("KVM dvmbm disabled\n"); + } + + return err; } void kvm_get_pg_cfg(void) diff --git a/arch/arm64/kvm/hisilicon/hisi_virt.h b/arch/arm64/kvm/hisilicon/hisi_virt.h index 8e7a88a267c8..0dfcbd81e1fc 100644 --- a/arch/arm64/kvm/hisilicon/hisi_virt.h +++ b/arch/arm64/kvm/hisilicon/hisi_virt.h @@ -95,6 +95,13 @@ enum hisi_cpu_type { void probe_hisi_cpu_type(void); bool hisi_ncsnp_supported(void); bool hisi_dvmbm_supported(void); + +extern bool tlbi_dvmbm_enable; +static inline bool kvm_dvmbm_enabled(void) +{ + return kvm_dvmbm_support && tlbi_dvmbm_enable; +} +int dvmbm_enable_update(const char *val, const struct kernel_param *kp); #ifdef CONFIG_ARM64_HISI_IPIV bool hisi_ipiv_supported(void); bool hisi_ipiv_supported_per_vm(struct kvm *kvm); @@ -120,6 +127,15 @@ static inline bool hisi_dvmbm_supported(void) { return false; } +static inline bool kvm_dvmbm_enabled(void) +{ + return false; +} +static inline int dvmbm_enable_update(const char *val, + const struct kernel_param *kp) +{ + return 0; +} #ifdef CONFIG_ARM64_HISI_IPIV static inline bool hisi_ipiv_supported(void) { -- 2.33.0

2 2