diff options
| -rw-r--r-- | kernel/hw_breakpoint.c | 63 |
1 files changed, 45 insertions, 18 deletions
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c index 8ead134..974498b8 100644 --- a/kernel/hw_breakpoint.c +++ b/kernel/hw_breakpoint.c @@ -77,6 +77,11 @@ struct bp_busy_slots { /* Serialize accesses to the above constraints */ static DEFINE_MUTEX(nr_bp_mutex); +__weak int hw_breakpoint_weight(struct perf_event *bp) +{ + return 1; +} + static inline enum bp_type_idx find_slot_idx(struct perf_event *bp) { if (bp->attr.bp_type & HW_BREAKPOINT_RW) @@ -124,7 +129,7 @@ static int task_bp_pinned(struct task_struct *tsk, enum bp_type_idx type) list_for_each_entry(bp, list, event_entry) { if (bp->attr.type == PERF_TYPE_BREAKPOINT) if (find_slot_idx(bp) == type) - count++; + count += hw_breakpoint_weight(bp); } raw_spin_unlock_irqrestore(&ctx->lock, flags); @@ -174,25 +179,40 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp, } /* + * For now, continue to consider flexible as pinned, until we can + * ensure no flexible event can ever be scheduled before a pinned event + * in a same cpu. + */ +static void +fetch_this_slot(struct bp_busy_slots *slots, int weight) +{ + slots->pinned += weight; +} + +/* * Add a pinned breakpoint for the given task in our constraint table */ static void toggle_bp_task_slot(struct task_struct *tsk, int cpu, bool enable, - enum bp_type_idx type) + enum bp_type_idx type, int weight) { unsigned int *tsk_pinned; - int count = 0; + int old_count = 0; + int old_idx = 0; + int idx = 0; - count = task_bp_pinned(tsk, type); + old_count = task_bp_pinned(tsk, type); + old_idx = old_count - 1; + idx = old_idx + weight; tsk_pinned = per_cpu(nr_task_bp_pinned[type], cpu); if (enable) { - tsk_pinned[count]++; - if (count > 0) - tsk_pinned[count-1]--; + tsk_pinned[idx]++; + if (old_count > 0) + tsk_pinned[old_idx]--; } else { - tsk_pinned[count]--; - if (count > 0) - tsk_pinned[count-1]++; + tsk_pinned[idx]--; + if (old_count > 0) + tsk_pinned[old_idx]++; } } @@ -200,7 +220,8 @@ static void toggle_bp_task_slot(struct task_struct *tsk, int cpu, bool enable, * Add/remove the given breakpoint in our constraint table */ static void -toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type) +toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type, + int weight) { int cpu = bp->cpu; struct task_struct *tsk = bp->ctx->task; @@ -208,20 +229,20 @@ toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type) /* Pinned counter task profiling */ if (tsk) { if (cpu >= 0) { - toggle_bp_task_slot(tsk, cpu, enable, type); + toggle_bp_task_slot(tsk, cpu, enable, type, weight); return; } for_each_online_cpu(cpu) - toggle_bp_task_slot(tsk, cpu, enable, type); + toggle_bp_task_slot(tsk, cpu, enable, type, weight); return; } /* Pinned counter cpu profiling */ if (enable) - per_cpu(nr_cpu_bp_pinned[type], bp->cpu)++; + per_cpu(nr_cpu_bp_pinned[type], bp->cpu) += weight; else - per_cpu(nr_cpu_bp_pinned[type], bp->cpu)--; + per_cpu(nr_cpu_bp_pinned[type], bp->cpu) -= weight; } /* @@ -269,6 +290,7 @@ static int __reserve_bp_slot(struct perf_event *bp) { struct bp_busy_slots slots = {0}; enum bp_type_idx type; + int weight; /* Basic checks */ if (bp->attr.bp_type == HW_BREAKPOINT_EMPTY || @@ -276,13 +298,16 @@ static int __reserve_bp_slot(struct perf_event *bp) return -EINVAL; type = find_slot_idx(bp); + weight = hw_breakpoint_weight(bp); + fetch_bp_busy_slots(&slots, bp, type); + fetch_this_slot(&slots, weight); /* Flexible counters need to keep at least one slot */ - if (slots.pinned + (!!slots.flexible) == HBP_NUM) + if (slots.pinned + (!!slots.flexible) > HBP_NUM) return -ENOSPC; - toggle_bp_slot(bp, true, type); + toggle_bp_slot(bp, true, type, weight); return 0; } @@ -303,9 +328,11 @@ int reserve_bp_slot(struct perf_event *bp) static void __release_bp_slot(struct perf_event *bp) { enum bp_type_idx type; + int weight; type = find_slot_idx(bp); - toggle_bp_slot(bp, false, type); + weight = hw_breakpoint_weight(bp); + toggle_bp_slot(bp, false, type, weight); } void release_bp_slot(struct perf_event *bp) |