Commit 657d4f79 authored by Barry Song's avatar Barry Song Committed by Linus Torvalds
Browse files

mm/gup_benchmark: use pin_user_pages for FOLL_LONGTERM flag 



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: default avatarBarry Song <song.bao.hua@hisilicon.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarJohn 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: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4c6cd03e

mm/gup_benchmark.c

+12 −11
Original line number Diff line number Diff line
@@ -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;

tools/testing/selftests/vm/gup_benchmark.c

+7 −7
Original line number Diff line number Diff line
@@ -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;

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