Messages in this thread Patch in this message | | | From | James Morse <> | Subject | [PATCH v4 15/24] x86/resctrl: Allow arch to allocate memory needed in resctrl_arch_rmid_read() | Date | Thu, 25 May 2023 18:02:00 +0000 |
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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.
add_rmid_to_limbo() calls resctrl_arch_rmid_read() for multiple domains, the allocation should be valid for all domains.
__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().
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.
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com> Signed-off-by: James Morse <james.morse@arm.com> ---- Changes since v3: * Expanded comment. * Removed stray header include. * Reworded commit message. * Made ctx a void * instead of an int. --- arch/x86/include/asm/resctrl.h | 11 ++++++++++ arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 5 +++++ arch/x86/kernel/cpu/resctrl/internal.h | 1 + arch/x86/kernel/cpu/resctrl/monitor.c | 26 +++++++++++++++++++---- include/linux/resctrl.h | 5 ++++- 5 files changed, 43 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/resctrl.h b/arch/x86/include/asm/resctrl.h index 78376c19ee6f..20729364982b 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 6eeccad192ee..280d66fae21c 100644 --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c @@ -546,6 +546,9 @@ 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)) + return; cpu = cpumask_any_housekeeping(&d->cpu_mask); @@ -559,6 +562,8 @@ 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 7960366b9434..a7e025cffdbc 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -136,6 +136,7 @@ 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 fb33100e172b..6d140018358a 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -264,7 +264,7 @@ 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 closid, 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); @@ -331,9 +331,14 @@ 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 (arch_mon_ctx < 0) + 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 @@ -347,7 +352,8 @@ 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); @@ -360,6 +366,8 @@ 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_resource *r, struct rdt_domain *d) @@ -539,7 +547,7 @@ 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; @@ -589,7 +597,6 @@ void mon_event_count(void *info) int ret; rdtgrp = rr->rgrp; - ret = __mon_event_count(rdtgrp->closid, rdtgrp->mon.rmid, rr); /* @@ -749,11 +756,21 @@ 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 (rr.arch_mon_ctx < 0) + 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 (rr.arch_mon_ctx < 0) + return; + __mon_event_count(closid, rmid, &rr); /* @@ -763,6 +780,7 @@ 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 b961936decfa..0dcb5cfde609 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -233,6 +233,9 @@ 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' @@ -246,7 +249,7 @@ 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 -- 2.39.2
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