From 4ff6a8debf48a7bf48e93c01da720785070d3a25 Mon Sep 17 00:00:00 2001 From: David Carrillo-Cisneros Date: Wed, 17 Aug 2016 13:55:05 -0700 Subject: [PATCH] perf/core: Generalize event->group_flags Currently, PERF_GROUP_SOFTWARE is used in the group_flags field of a group's leader to indicate that is_software_event(event) is true for all events in a group. This is the only usage of event->group_flags. This pattern of setting a group level flags when all events in the group share a property is useful for the flag introduced in the next patch and for future CQM/CMT flags. So this patches generalizes group_flags to work as an aggregate of event level flags. PERF_GROUP_SOFTWARE denotes an inmutable event's property. All other flags that I intend to add are also determinable at event initialization. To better convey the above, this patch renames event's group_flags to group_caps and PERF_GROUP_SOFTWARE to PERF_EV_CAP_SOFTWARE. Individual event flags are stored in the new event->event_caps. Since the cap flags do not change after event initialization, there is no need to serialize event_caps. This new field is used when events are added to a context, similarly to how PERF_GROUP_SOFTWARE and is_software_event() worked. Lastly, for consistency, updates is_software_event() to rely in event_cap instead of the context index. Signed-off-by: David Carrillo-Cisneros Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Kan Liang Cc: Linus Torvalds Cc: Paul Turner Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vegard Nossum Cc: Vince Weaver Link: http://lkml.kernel.org/r/1471467307-61171-3-git-send-email-davidcc@google.com Signed-off-by: Ingo Molnar --- include/linux/perf_event.h | 18 +++++++++++++----- kernel/events/core.c | 16 ++++++++-------- 2 files changed, 21 insertions(+), 13 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 529c41fa73c8..6f7459f72dfd 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -510,9 +510,12 @@ typedef void (*perf_overflow_handler_t)(struct perf_event *, struct perf_sample_data *, struct pt_regs *regs); -enum perf_group_flag { - PERF_GROUP_SOFTWARE = 0x1, -}; +/* + * Event capabilities. For event_caps and groups caps. + * + * PERF_EV_CAP_SOFTWARE: Is a software event. + */ +#define PERF_EV_CAP_SOFTWARE BIT(0) #define SWEVENT_HLIST_BITS 8 #define SWEVENT_HLIST_SIZE (1 << SWEVENT_HLIST_BITS) @@ -568,7 +571,12 @@ struct perf_event { struct hlist_node hlist_entry; struct list_head active_entry; int nr_siblings; - int group_flags; + + /* Not serialized. Only written during event initialization. */ + int event_caps; + /* The cumulative AND of all event_caps for events in this group. */ + int group_caps; + struct perf_event *group_leader; struct pmu *pmu; void *pmu_private; @@ -988,7 +996,7 @@ static inline bool is_sampling_event(struct perf_event *event) */ static inline int is_software_event(struct perf_event *event) { - return event->pmu->task_ctx_nr == perf_sw_context; + return event->event_caps & PERF_EV_CAP_SOFTWARE; } extern struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; diff --git a/kernel/events/core.c b/kernel/events/core.c index 849919c2f3d7..8c42a5ae9030 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1475,8 +1475,7 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx) if (event->group_leader == event) { struct list_head *list; - if (is_software_event(event)) - event->group_flags |= PERF_GROUP_SOFTWARE; + event->group_caps = event->event_caps; list = ctx_group_list(event, ctx); list_add_tail(&event->group_entry, list); @@ -1630,9 +1629,7 @@ static void perf_group_attach(struct perf_event *event) WARN_ON_ONCE(group_leader->ctx != event->ctx); - if (group_leader->group_flags & PERF_GROUP_SOFTWARE && - !is_software_event(event)) - group_leader->group_flags &= ~PERF_GROUP_SOFTWARE; + group_leader->group_caps &= event->event_caps; list_add_tail(&event->group_entry, &group_leader->sibling_list); group_leader->nr_siblings++; @@ -1723,7 +1720,7 @@ static void perf_group_detach(struct perf_event *event) sibling->group_leader = sibling; /* Inherit group flags from the previous leader */ - sibling->group_flags = event->group_flags; + sibling->group_caps = event->group_caps; WARN_ON_ONCE(sibling->ctx != event->ctx); } @@ -2149,7 +2146,7 @@ static int group_can_go_on(struct perf_event *event, /* * Groups consisting entirely of software events can always go on. */ - if (event->group_flags & PERF_GROUP_SOFTWARE) + if (event->group_caps & PERF_EV_CAP_SOFTWARE) return 1; /* * If an exclusive group is already on, no other hardware @@ -9490,6 +9487,9 @@ SYSCALL_DEFINE5(perf_event_open, goto err_alloc; } + if (pmu->task_ctx_nr == perf_sw_context) + event->event_caps |= PERF_EV_CAP_SOFTWARE; + if (group_leader && (is_software_event(event) != is_software_event(group_leader))) { if (is_software_event(event)) { @@ -9503,7 +9503,7 @@ SYSCALL_DEFINE5(perf_event_open, */ pmu = group_leader->pmu; } else if (is_software_event(group_leader) && - (group_leader->group_flags & PERF_GROUP_SOFTWARE)) { + (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { /* * In case the group is a pure software group, and we * try to add a hardware event, move the whole group to -- GitLab