On 8/15/20 5:20 AM, Barry Song wrote:
According to Documentation/core-api/pin_user_pages.rst, FOLL_PIN is a
prerequisite to FOLL_LONGTERM. Another way of saying that is,
FOLL_LONGTERM is a specific case, more restrictive case of FOLL_PIN.
Almost all kernel modules are using pin_user_pages() with FOLL_LONGTERM,
mm/gup_benchmark.c seems to the only exception in which FOLL_PIN is not
a prerequisite to FOLL_LONGTERM.
Cc: John Hubbard <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jérôme Glisse <[email protected]>
Cc: "Matthew Wilcox (Oracle)" <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Mike Kravetz <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Barry Song <[email protected]>
---
mm/gup_benchmark.c | 23 +++++++++++-----------
tools/testing/selftests/vm/gup_benchmark.c | 14 ++++++-------
2 files changed, 19 insertions(+), 18 deletions(-)
DKIM-Signature: v a nr = get_user_pages(addr, nr,
gup->flags, pages + i,
NULL);
@@ -118,6 +114,11 @@ static int __gup_benchmark_ioctl(unsigned int cmd,
nr = pin_user_pages(addr, nr, gup->flags, pages + i,
NULL);
break;
+ case PIN_LONGTERM_BENCHMARK:
+ nr = pin_user_pages(addr, nr,
+ gup->flags | FOLL_LONGTERM,
+ pages + i, NULL);
+ break;
default:
kvfree(pages);
ret = -EINVAL;
@@ -162,10 +163,10 @@ static long gup_benchmark_ioctl(struct file *filep,
unsigned int cmd,
switch (cmd) {
case GUP_FAST_BENCHMARK:
- case GUP_LONGTERM_BENCHMARK:
case GUP_BENCHMARK:
case PIN_FAST_BENCHMARK:
case PIN_BENCHMARK:
+ case PIN_LONGTERM_BENCHMARK:
break;
default:
return -EINVAL;
diff --git a/tools/testing/selftests/vm/gup_benchmark.c
b/tools/testing/selftests/vm/gup_benchmark.c
index 43b4dfe161a2..31f8bb086907 100644
--- a/tools/testing/selftests/vm/gup_benchmark.c
+++ b/tools/testing/selftests/vm/gup_benchmark.c
@@ -15,12 +15,12 @@
#define PAGE_SIZE sysconf(_SC_PAGESIZE)
#define GUP_FAST_BENCHMARK _IOWR('g', 1, struct gup_benchmark)
-#define GUP_LONGTERM_BENCHMARK _IOWR('g', 2, struct gup_benchmark)
-#define GUP_BENCHMARK _IOWR('g', 3, struct gup_benchmark)
+#define GUP_BENCHMARK _IOWR('g', 2, struct gup_benchmark)
/* Similar to above, but use FOLL_PIN instead of FOLL_GET. */
-#define PIN_FAST_BENCHMARK _IOWR('g', 4, struct gup_benchmark)
-#define PIN_BENCHMARK _IOWR('g', 5, struct gup_benchmark)
+#define PIN_FAST_BENCHMARK _IOWR('g', 3, struct gup_benchmark)
+#define PIN_BENCHMARK _IOWR('g', 4, struct gup_benchmark)
+#define PIN_LONGTERM_BENCHMARK _IOWR('g', 5, struct gup_benchmark)
/* Just the flags we need, copied from mm.h: */
#define FOLL_WRITE 0x01 /* check pte is writable */
@@ -52,6 +52,9 @@ int main(int argc, char **argv)
case 'b':
cmd = PIN_BENCHMARK;
break;
+ case 'L':
+ cmd = PIN_LONGTERM_BENCHMARK;
+ break;
case 'm':
size = atoi(optarg) * MB;
break;
@@ -67,9 +70,6 @@ int main(int argc, char **argv)
case 'T':
thp = 0;
break;
- case 'L':
- cmd = GUP_LONGTERM_BENCHMARK;
- break;
case 'U':
cmd = GUP_BENCHMARK;
break;
