s390/pai_ext: Enable per-task and system-wide sampling event

The PMU for PAI NNPA counters enforces the following restriction:

 - No per-task context for PAI sampling event NNPA_ALL
 - No multiple system-wide PAI sampling event NNPA_ALL

Both restrictions are removed. One or more per-task sampling events
are supported. Also one or more system-wide sampling events are
supported.

Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/arch/s390/include/asm/pai.h b/arch/s390/include/asm/pai.h
index 7da1cec42016e10c47b1eae82dcae954d6e1b83d..8e1dd389ae88f687499fea4868ed445a72b95845 100644 (file)
--- a/arch/s390/include/asm/pai.h
+++ b/arch/s390/include/asm/pai.h
@@ -75,12 +75,8 @@ static __always_inline void pai_kernel_exit(struct pt_regs *regs)
        WRITE_ONCE(S390_lowcore.ccd, S390_lowcore.ccd & ~PAI_CRYPTO_KERNEL_OFFSET);
 }
 
-enum paievt_mode {
-       PAI_MODE_NONE,
-       PAI_MODE_SAMPLING,
-       PAI_MODE_COUNTING,
-};
-
 #define PAI_SAVE_AREA(x)       ((x)->hw.event_base)
 #define PAI_CPU_MASK(x)                ((x)->hw.addr_filters)
+#define PAI_SWLIST(x)          (&(x)->hw.tp_list)
+
 #endif

diff --git a/arch/s390/kernel/perf_pai_crypto.c b/arch/s390/kernel/perf_pai_crypto.c
index c0b7f5422e5e766c7272e50ac084fab905b4d5e5..95079a2891098cb739c92e6ce75829c76eec8125 100644 (file)
--- a/arch/s390/kernel/perf_pai_crypto.c
+++ b/arch/s390/kernel/perf_pai_crypto.c
@@ -24,8 +24,6 @@ static debug_info_t *cfm_dbg;
 static unsigned int paicrypt_cnt;      /* Size of the mapped counter sets */
                                        /* extracted with QPACI instruction */
 
-#define PAI_SWLIST(x)          (&(x)->hw.tp_list)
-
 DEFINE_STATIC_KEY_FALSE(pai_key);
 
 struct pai_userdata {

diff --git a/arch/s390/kernel/perf_pai_ext.c b/arch/s390/kernel/perf_pai_ext.c
index 20fc12dd9d0dd7a6a74c0c6c688a0b6fd4cc390b..6040f3c2b94244b336f20b62991d743ff9ca274d 100644 (file)
--- a/arch/s390/kernel/perf_pai_ext.c
+++ b/arch/s390/kernel/perf_pai_ext.c
@@ -47,11 +47,11 @@ struct paiext_cb {          /* PAI extension 1 control block */
 struct paiext_map {
        unsigned long *area;            /* Area for CPU to store counters */
        struct pai_userdata *save;      /* Area to store non-zero counters */
-       enum paievt_mode mode;          /* Type of event */
        unsigned int active_events;     /* # of PAI Extension users */
        refcount_t refcnt;
        struct perf_event *event;       /* Perf event for sampling */
        struct paiext_cb *paiext_cb;    /* PAI extension control block area */
+       struct list_head syswide_list;  /* List system-wide sampling events */
 };
 
 struct paiext_mapptr {
@@ -70,6 +70,8 @@ static void paiext_root_free(void)
                free_percpu(paiext_root.mapptr);
                paiext_root.mapptr = NULL;
        }
+       debug_sprintf_event(paiext_dbg, 5, "%s root.refcount %d\n", __func__,
+                           refcount_read(&paiext_root.refcnt));
 }
 
 /* On initialization of first event also allocate per CPU data dynamically.
@@ -121,8 +123,6 @@ static void paiext_event_destroy_cpu(struct perf_event *event, int cpu)
        struct paiext_map *cpump = mp->mapptr;
 
        mutex_lock(&paiext_reserve_mutex);
-       if (event->attr.sample_period)
-               cpump->mode &= ~PAI_MODE_SAMPLING;
        if (refcount_dec_and_test(&cpump->refcnt))      /* Last reference gone */
                paiext_free(mp);
        paiext_root_free();
@@ -161,7 +161,7 @@ static void paiext_event_destroy(struct perf_event *event)
  *
  * Allocate the memory for the event.
  */
-static int paiext_alloc_cpu(struct perf_event_attr *a, int cpu)
+static int paiext_alloc_cpu(struct perf_event *event, int cpu)
 {
        struct paiext_mapptr *mp;
        struct paiext_map *cpump;
@@ -200,21 +200,12 @@ static int paiext_alloc_cpu(struct perf_event_attr *a, int cpu)
                        paiext_free(mp);
                        goto undo;
                }
+               INIT_LIST_HEAD(&cpump->syswide_list);
                refcount_set(&cpump->refcnt, 1);
+               rc = 0;
        } else {
-               /* Multiple invocation, check what is active.
-                * Supported are multiple counter events and only one sampling
-                * event concurrently at any one time.
-                */
-               if (a->sample_period && (cpump->mode & PAI_MODE_SAMPLING)) {
-                       rc = -EBUSY;
-                       goto undo;
-               }
                refcount_inc(&cpump->refcnt);
        }
-       if (a->sample_period)
-               cpump->mode |= PAI_MODE_SAMPLING;
-       rc = 0;
 
 undo:
        if (rc) {
@@ -240,7 +231,7 @@ static int paiext_alloc(struct perf_event *event)
                goto out;
 
        for_each_online_cpu(cpu) {
-               rc = paiext_alloc_cpu(&event->attr, cpu);
+               rc = paiext_alloc_cpu(event, cpu);
                if (rc) {
                        for_each_cpu(cpu, maskptr)
                                paiext_event_destroy_cpu(event, cpu);
@@ -259,8 +250,6 @@ static int paiext_alloc(struct perf_event *event)
        PAI_CPU_MASK(event) = maskptr;
        rc = 0;
 out:
-       debug_sprintf_event(paiext_dbg, 5, "%s cpu %u rc %d\n", __func__,
-                           cpu, rc);
        return rc;
 }
 
@@ -293,10 +282,6 @@ static int paiext_event_init(struct perf_event *event)
        rc = paiext_event_valid(event);
        if (rc)
                return rc;
-       /* Allow only CPU wide operation for sampling */
-       if (a->sample_period &&
-           ((event->attach_state & PERF_ATTACH_TASK) || event->cpu == -1))
-               return -ENOENT;
        /* Allow only event NNPA_ALL for sampling. */
        if (a->sample_period && a->config != PAI_NNPA_BASE)
                return -EINVAL;
@@ -311,7 +296,7 @@ static int paiext_event_init(struct perf_event *event)
        }
 
        if (event->cpu >= 0)
-               rc = paiext_alloc_cpu(a, event->cpu);
+               rc = paiext_alloc_cpu(event, event->cpu);
        else
                rc = paiext_alloc(event);
        if (rc) {
@@ -385,10 +370,15 @@ static void paiext_start(struct perf_event *event, int flags)
                sum = paiext_getall(event);     /* Get current value */
                local64_set(&event->hw.prev_count, sum);
        } else {                                /* Sampling */
-               cpump->event = event;
                memcpy((void *)PAI_SAVE_AREA(event), cpump->area,
                       PAIE1_CTRBLOCK_SZ);
-               perf_sched_cb_inc(event->pmu);
+               /* Enable context switch callback for system-wide sampling */
+               if (!(event->attach_state & PERF_ATTACH_TASK)) {
+                       list_add_tail(PAI_SWLIST(event), &cpump->syswide_list);
+                       perf_sched_cb_inc(event->pmu);
+               } else {
+                       cpump->event = event;
+               }
        }
 }
 
@@ -410,6 +400,7 @@ static int paiext_add(struct perf_event *event, int flags)
        return 0;
 }
 
+static void paiext_have_sample(struct perf_event *, struct paiext_map *);
 static void paiext_stop(struct perf_event *event, int flags)
 {
        struct paiext_mapptr *mp = this_cpu_ptr(paiext_root.mapptr);
@@ -418,8 +409,13 @@ static void paiext_stop(struct perf_event *event, int flags)
        if (!event->attr.sample_period) {       /* Counting */
                paiext_read(event);
        } else {                                /* Sampling */
-               perf_sched_cb_dec(event->pmu);
-               cpump->event = NULL;
+               if (!(event->attach_state & PERF_ATTACH_TASK)) {
+                       list_del(PAI_SWLIST(event));
+                       perf_sched_cb_dec(event->pmu);
+               } else {
+                       paiext_have_sample(event, cpump);
+                       cpump->event = NULL;
+               }
        }
        event->hw.state = PERF_HES_STOPPED;
 }
@@ -519,21 +515,28 @@ static int paiext_push_sample(size_t rawsize, struct paiext_map *cpump,
 }
 
 /* Check if there is data to be saved on schedule out of a task. */
-static int paiext_have_sample(void)
+static void paiext_have_sample(struct perf_event *event,
+                              struct paiext_map *cpump)
 {
-       struct paiext_mapptr *mp = this_cpu_ptr(paiext_root.mapptr);
-       struct paiext_map *cpump = mp->mapptr;
-       struct perf_event *event = cpump->event;
        size_t rawsize;
-       int rc = 0;
 
        if (!event)
-               return 0;
+               return;
        rawsize = paiext_copy(cpump->save, cpump->area,
                              (unsigned long *)PAI_SAVE_AREA(event));
        if (rawsize)                    /* Incremented counters */
-               rc = paiext_push_sample(rawsize, cpump, event);
-       return rc;
+               paiext_push_sample(rawsize, cpump, event);
+}
+
+/* Check if there is data to be saved on schedule out of a task. */
+static void paiext_have_samples(void)
+{
+       struct paiext_mapptr *mp = this_cpu_ptr(paiext_root.mapptr);
+       struct paiext_map *cpump = mp->mapptr;
+       struct perf_event *event;
+
+       list_for_each_entry(event, &cpump->syswide_list, hw.tp_list)
+               paiext_have_sample(event, cpump);
 }
 
 /* Called on schedule-in and schedule-out. No access to event structure,
@@ -545,7 +548,7 @@ static void paiext_sched_task(struct perf_event_pmu_context *pmu_ctx, bool sched
         * results on schedule_out and if page was dirty, save old values.
         */
        if (!sched_in)
-               paiext_have_sample();
+               paiext_have_samples();
 }
 
 /* Attribute definitions for pai extension1 interface. As with other CPU