From: Yicong Yang yangyicong@hisilicon.com
Currently the perf buffer allocation follows the below logic: - if the required AUX buffer size if larger, allocate the buffer with the required size - otherwise allocate the size reference to the sysfs buffer size
This is not useful as we only collect to one AUX data, so just try to allocate the buffer match the AUX buffer size.
Suggested-by: Suzuki K Poulose suzuki.poulose@arm.com Link: https://lore.kernel.org/linux-arm-kernel/df8967cd-2157-46a2-97d9-a1aea883cf6... Signed-off-by: Yicong Yang yangyicong@hisilicon.com Signed-off-by: Junhao He hejunhao3@huawei.com --- .../hwtracing/coresight/coresight-tmc-etr.c | 30 ++++++------------- 1 file changed, 9 insertions(+), 21 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 06c74717be19..af12d6b98030 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1344,9 +1344,7 @@ EXPORT_SYMBOL_GPL(tmc_etr_get_buffer);
/* * alloc_etr_buf: Allocate ETR buffer for use by perf. - * The size of the hardware buffer is dependent on the size configured - * via sysfs and the perf ring buffer size. We prefer to allocate the - * largest possible size, scaling down the size by half until it + * Allocate the largest possible size, scaling down the size by half until it * reaches a minimum limit (1M), beyond which we give up. */ static struct etr_buf * @@ -1355,36 +1353,26 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event, { int node; struct etr_buf *etr_buf; - unsigned long size; + ssize_t size;
node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu); - /* - * Try to match the perf ring buffer size if it is larger - * than the size requested via sysfs. - */ - if ((nr_pages << PAGE_SHIFT) > drvdata->size) { - etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages << PAGE_SHIFT), - 0, node, NULL); - if (!IS_ERR(etr_buf)) - goto done; - } + + /* Use the minimum limit if the required size is smaller */ + size = nr_pages << PAGE_SHIFT; + size = max_t(ssize_t, size, TMC_ETR_PERF_MIN_BUF_SIZE);
/* - * Else switch to configured size for this ETR - * and scale down until we hit the minimum limit. + * Try to allocate the required size for this ETR, if failed scale + * down until we hit the minimum limit. */ - size = drvdata->size; do { etr_buf = tmc_alloc_etr_buf(drvdata, size, 0, node, NULL); if (!IS_ERR(etr_buf)) - goto done; + return etr_buf; size /= 2; } while (size >= TMC_ETR_PERF_MIN_BUF_SIZE);
return ERR_PTR(-ENOMEM); - -done: - return etr_buf; }
static struct etr_buf *