From e557999f80a5ee4ec812f594ab42bb76c3ec4eb2 Mon Sep 17 00:00:00 2001 From: James Morse Date: Tue, 13 Feb 2024 18:44:29 +0000 Subject: [PATCH] x86/resctrl: Allow arch to allocate memory needed in resctrl_arch_rmid_read() Depending on the number of monitors available, Arm's MPAM may need to allocate a monitor prior to reading the counter value. Allocating a contended resource may involve sleeping. __check_limbo() and mon_event_count() each make multiple calls to resctrl_arch_rmid_read(), to avoid extra work on contended systems, the allocation should be valid for multiple invocations of resctrl_arch_rmid_read(). The memory or hardware allocated is not specific to a domain. Add arch hooks for this allocation, which need calling before resctrl_arch_rmid_read(). The allocated monitor is passed to resctrl_arch_rmid_read(), then freed again afterwards. The helper can be called on any CPU, and can sleep. Signed-off-by: James Morse Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Shaopeng Tan Reviewed-by: Reinette Chatre Reviewed-by: Babu Moger Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Babu Moger Tested-by: Carl Worth # arm64 Link: https://lore.kernel.org/r/20240213184438.16675-16-james.morse@arm.com Signed-off-by: Borislav Petkov (AMD) --- arch/x86/include/asm/resctrl.h | 11 +++++++ arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 7 +++++ arch/x86/kernel/cpu/resctrl/internal.h | 1 + arch/x86/kernel/cpu/resctrl/monitor.c | 35 +++++++++++++++++++++-- include/linux/resctrl.h | 5 +++- 5 files changed, 55 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/resctrl.h b/arch/x86/include/asm/resctrl.h index 1d274dbabc44..29c4cc343787 100644 --- a/arch/x86/include/asm/resctrl.h +++ b/arch/x86/include/asm/resctrl.h @@ -136,6 +136,17 @@ static inline u32 resctrl_arch_rmid_idx_encode(u32 ignored, u32 rmid) return rmid; } +/* x86 can always read an rmid, nothing needs allocating */ +struct rdt_resource; +static inline void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r, int evtid) +{ + might_sleep(); + return NULL; +}; + +static inline void resctrl_arch_mon_ctx_free(struct rdt_resource *r, int evtid, + void *ctx) { }; + void resctrl_cpu_detect(struct cpuinfo_x86 *c); #else diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c index e933e1cdb1c9..52fa0e14cb86 100644 --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c @@ -546,6 +546,11 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, rr->d = d; rr->val = 0; rr->first = first; + rr->arch_mon_ctx = resctrl_arch_mon_ctx_alloc(r, evtid); + if (IS_ERR(rr->arch_mon_ctx)) { + rr->err = -EINVAL; + return; + } cpu = cpumask_any_housekeeping(&d->cpu_mask); @@ -559,6 +564,8 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, smp_call_function_any(&d->cpu_mask, mon_event_count, rr, 1); else smp_call_on_cpu(cpu, smp_mon_event_count, rr, false); + + resctrl_arch_mon_ctx_free(r, evtid, rr->arch_mon_ctx); } int rdtgroup_mondata_show(struct seq_file *m, void *arg) diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index 81f5de916db8..e089d1a1a055 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -137,6 +137,7 @@ struct rmid_read { bool first; int err; u64 val; + void *arch_mon_ctx; }; extern bool rdt_alloc_capable; diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c index e8aeff6673ea..9b503e6ac490 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -269,7 +269,7 @@ static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr, unsigned int width) int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, u32 unused, u32 rmid, enum resctrl_event_id eventid, - u64 *val) + u64 *val, void *ignored) { struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r); struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d); @@ -324,9 +324,17 @@ void __check_limbo(struct rdt_domain *d, bool force_free) u32 idx_limit = resctrl_arch_system_num_rmid_idx(); struct rmid_entry *entry; u32 idx, cur_idx = 1; + void *arch_mon_ctx; bool rmid_dirty; u64 val = 0; + arch_mon_ctx = resctrl_arch_mon_ctx_alloc(r, QOS_L3_OCCUP_EVENT_ID); + if (IS_ERR(arch_mon_ctx)) { + pr_warn_ratelimited("Failed to allocate monitor context: %ld", + PTR_ERR(arch_mon_ctx)); + return; + } + /* * Skip RMID 0 and start from RMID 1 and check all the RMIDs that * are marked as busy for occupancy < threshold. If the occupancy @@ -340,7 +348,8 @@ void __check_limbo(struct rdt_domain *d, bool force_free) entry = __rmid_entry(idx); if (resctrl_arch_rmid_read(r, d, entry->closid, entry->rmid, - QOS_L3_OCCUP_EVENT_ID, &val)) { + QOS_L3_OCCUP_EVENT_ID, &val, + arch_mon_ctx)) { rmid_dirty = true; } else { rmid_dirty = (val >= resctrl_rmid_realloc_threshold); @@ -353,6 +362,8 @@ void __check_limbo(struct rdt_domain *d, bool force_free) } cur_idx = idx + 1; } + + resctrl_arch_mon_ctx_free(r, QOS_L3_OCCUP_EVENT_ID, arch_mon_ctx); } bool has_busy_rmid(struct rdt_domain *d) @@ -533,7 +544,7 @@ static int __mon_event_count(u32 closid, u32 rmid, struct rmid_read *rr) } rr->err = resctrl_arch_rmid_read(rr->r, rr->d, closid, rmid, rr->evtid, - &tval); + &tval, rr->arch_mon_ctx); if (rr->err) return rr->err; @@ -722,11 +733,27 @@ static void mbm_update(struct rdt_resource *r, struct rdt_domain *d, if (is_mbm_total_enabled()) { rr.evtid = QOS_L3_MBM_TOTAL_EVENT_ID; rr.val = 0; + rr.arch_mon_ctx = resctrl_arch_mon_ctx_alloc(rr.r, rr.evtid); + if (IS_ERR(rr.arch_mon_ctx)) { + pr_warn_ratelimited("Failed to allocate monitor context: %ld", + PTR_ERR(rr.arch_mon_ctx)); + return; + } + __mon_event_count(closid, rmid, &rr); + + resctrl_arch_mon_ctx_free(rr.r, rr.evtid, rr.arch_mon_ctx); } if (is_mbm_local_enabled()) { rr.evtid = QOS_L3_MBM_LOCAL_EVENT_ID; rr.val = 0; + rr.arch_mon_ctx = resctrl_arch_mon_ctx_alloc(rr.r, rr.evtid); + if (IS_ERR(rr.arch_mon_ctx)) { + pr_warn_ratelimited("Failed to allocate monitor context: %ld", + PTR_ERR(rr.arch_mon_ctx)); + return; + } + __mon_event_count(closid, rmid, &rr); /* @@ -736,6 +763,8 @@ static void mbm_update(struct rdt_resource *r, struct rdt_domain *d, */ if (is_mba_sc(NULL)) mbm_bw_count(closid, rmid, &rr); + + resctrl_arch_mon_ctx_free(rr.r, rr.evtid, rr.arch_mon_ctx); } } diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index 8649fc84aac2..bf460c912bf5 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -235,6 +235,9 @@ void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d); * @rmid: rmid of the counter to read. * @eventid: eventid to read, e.g. L3 occupancy. * @val: result of the counter read in bytes. + * @arch_mon_ctx: An architecture specific value from + * resctrl_arch_mon_ctx_alloc(), for MPAM this identifies + * the hardware monitor allocated for this read request. * * Some architectures need to sleep when first programming some of the counters. * (specifically: arm64's MPAM cache occupancy counters can return 'not ready' @@ -248,7 +251,7 @@ void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d); */ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, u32 closid, u32 rmid, enum resctrl_event_id eventid, - u64 *val); + u64 *val, void *arch_mon_ctx); /** * resctrl_arch_rmid_read_context_check() - warn about invalid contexts