diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-06-02 16:16:02 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-06-02 21:45:32 +0200 |
| commit | 8e3747c13c39246c7e46def7cf495d9d21d4c5f9 (patch) | |
| tree | 6a57736dd784947dbd40b75674effcb63e6696a1 | |
| parent | e4abb5d4f7ddabc1fc7c392cf0a10d8e5868c9ca (diff) | |
perf_counter: Change data head from u32 to u64
Since some people worried that 4G might not be a large enough
as an mmap data window, extend it to 64 bit for capable
platforms.
Reported-by: Stephane Eranian <eranian@googlemail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | include/linux/perf_counter.h | 7 | ||||
| -rw-r--r-- | kernel/perf_counter.c | 15 |
2 files changed, 12 insertions, 10 deletions
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index cef9931793f..c046f7d97cf 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -212,7 +212,7 @@ struct perf_counter_mmap_page { * User-space reading this value should issue an rmb(), on SMP capable * platforms, after reading this value -- see perf_counter_wakeup(). */ - __u32 data_head; /* head in the data section */ + __u64 data_head; /* head in the data section */ }; #define PERF_EVENT_MISC_CPUMODE_MASK (3 << 0) @@ -397,10 +397,11 @@ struct perf_mmap_data { int nr_locked; /* nr pages mlocked */ atomic_t poll; /* POLL_ for wakeups */ - atomic_t head; /* write position */ atomic_t events; /* event limit */ - atomic_t done_head; /* completed head */ + atomic_long_t head; /* write position */ + atomic_long_t done_head; /* completed head */ + atomic_t lock; /* concurrent writes */ atomic_t wakeup; /* needs a wakeup */ diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 5ecd9981c03..3f11a2bc6c7 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -2067,8 +2067,8 @@ __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) struct perf_output_handle { struct perf_counter *counter; struct perf_mmap_data *data; - unsigned int offset; - unsigned int head; + unsigned long head; + unsigned long offset; int nmi; int overflow; int locked; @@ -2122,7 +2122,8 @@ static void perf_output_lock(struct perf_output_handle *handle) static void perf_output_unlock(struct perf_output_handle *handle) { struct perf_mmap_data *data = handle->data; - int head, cpu; + unsigned long head; + int cpu; data->done_head = data->head; @@ -2135,7 +2136,7 @@ again: * before we publish the new head, matched by a rmb() in userspace when * reading this position. */ - while ((head = atomic_xchg(&data->done_head, 0))) + while ((head = atomic_long_xchg(&data->done_head, 0))) data->user_page->data_head = head; /* @@ -2148,7 +2149,7 @@ again: /* * Therefore we have to validate we did not indeed do so. */ - if (unlikely(atomic_read(&data->done_head))) { + if (unlikely(atomic_long_read(&data->done_head))) { /* * Since we had it locked, we can lock it again. */ @@ -2195,7 +2196,7 @@ static int perf_output_begin(struct perf_output_handle *handle, do { offset = head = atomic_read(&data->head); head += size; - } while (atomic_cmpxchg(&data->head, offset, head) != offset); + } while (atomic_long_cmpxchg(&data->head, offset, head) != offset); handle->offset = offset; handle->head = head; @@ -2246,7 +2247,7 @@ static void perf_output_copy(struct perf_output_handle *handle, * Check we didn't copy past our reservation window, taking the * possible unsigned int wrap into account. */ - WARN_ON_ONCE(((int)(handle->head - handle->offset)) < 0); + WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0); } #define perf_output_put(handle, x) \ |