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mm/gup_benchmark: use pin_user_pages for FOLL_LONGTERM flag

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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.

Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200815122056.29508-1-song.bao.hua@hisilicon.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Barry Song 2020-10-13 16:51:54 -07:00 committed by Linus Torvalds
parent 4c6cd03ed8
commit 657d4f7996
2 changed files with 19 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
mm/gup_benchmark.c
View File

@ -6,10 +6,10 @@
#include <linux/debugfs.h>
#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 PIN_FAST_BENCHMARK _IOWR('g', 4, struct gup_benchmark)
#define PIN_BENCHMARK _IOWR('g', 5, struct gup_benchmark)
#define GUP_BENCHMARK _IOWR('g', 2, 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)
struct gup_benchmark {
__u64 get_delta_usec;
@ -28,7 +28,6 @@ static void put_back_pages(unsigned int cmd, struct page **pages,
switch (cmd) {
case GUP_FAST_BENCHMARK:
case GUP_LONGTERM_BENCHMARK:
case GUP_BENCHMARK:
for (i = 0; i < nr_pages; i++)
put_page(pages[i]);
@ -36,6 +35,7 @@ static void put_back_pages(unsigned int cmd, struct page **pages,
case PIN_FAST_BENCHMARK:
case PIN_BENCHMARK:
case PIN_LONGTERM_BENCHMARK:
unpin_user_pages(pages, nr_pages);
break;
}
@ -50,6 +50,7 @@ static void verify_dma_pinned(unsigned int cmd, struct page **pages,
switch (cmd) {
case PIN_FAST_BENCHMARK:
case PIN_BENCHMARK:
case PIN_LONGTERM_BENCHMARK:
for (i = 0; i < nr_pages; i++) {
page = pages[i];
if (WARN(!page_maybe_dma_pinned(page),
@ -101,11 +102,6 @@ static int __gup_benchmark_ioctl(unsigned int cmd,
nr = get_user_pages_fast(addr, nr, gup->flags,
pages + i);
break;
case GUP_LONGTERM_BENCHMARK:
nr = get_user_pages(addr, nr,
gup->flags | FOLL_LONGTERM,
pages + i, NULL);
break;
case GUP_BENCHMARK:
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;

14
tools/testing/selftests/vm/gup_benchmark.c
View File

@ -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;