On Thu, May 09, 2019 at 11:35:59AM +0100, Sudeep Holla wrote:
> On Thu, May 09, 2019 at 10:28:11AM +0100, Will Deacon wrote:
[...]
> >
> > Since SPE uses virtual addressing, we don't really care about the underlying
> > page layout so there's no need to use higher-order allocations. I suppose we
> > could theoretically map them at the pmd level in some cases, but ignoring
> > them should also be harmless and I suspect you can delete the check.
> >
>
> Yes, I did a quick look to see if we can do that, but couldn't find a clue.
> Not sure if that's any optimisation, we can use order from page_private
> and set the values accordingly ?
>
And I forgot to add the diff that I mentioned above, something like the
patch below.
Regards,
Sudeep
-->8
diff --git i/drivers/perf/arm_spe_pmu.c w/drivers/perf/arm_spe_pmu.c
index 7cb766dafe85..45cd62517080 100644
--- i/drivers/perf/arm_spe_pmu.c
+++ w/drivers/perf/arm_spe_pmu.c
@@ -827,7 +827,7 @@ static void arm_spe_pmu_read(struct perf_event *event)
static void *arm_spe_pmu_setup_aux(struct perf_event *event, void **pages,
int nr_pages, bool snapshot)
{
- int i, cpu = event->cpu;
+ int i, j, cpu = event->cpu;
struct page **pglist;
struct arm_spe_pmu_buf *buf;
@@ -859,11 +859,12 @@ static void *arm_spe_pmu_setup_aux(struct perf_event *event, void **pages,
struct page *page = virt_to_page(pages[i]);
if (PagePrivate(page)) {
- pr_warn("unexpected high-order page for auxbuf!");
- goto out_free_pglist;
+ for (j = 0; j < 1 << page_private(page); j++)
+ pglist[i + j] = page++;
+ i += j - 1;
+ } else {
+ pglist[i] = page;
}
-
- pglist[i] = virt_to_page(pages[i]);
}
buf->base = vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL);
