From: Barry Song <song.bao.hua@xxxxxxxxxxxxx> Subject: 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. Link: http://lkml.kernel.org/r/20200815122056.29508-1-song.bao.hua@xxxxxxxxxxxxx Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx> Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx> Cc: Jan Kara <jack@xxxxxxx> Cc: Jérôme Glisse <jglisse@xxxxxxxxxx> Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: Jason Gunthorpe <jgg@xxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Shuah Khan <shuah@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/gup_benchmark.c | 23 +++++++++---------- tools/testing/selftests/vm/gup_benchmark.c | 14 +++++------ 2 files changed, 19 insertions(+), 18 deletions(-) --- a/mm/gup_benchmark.c~mm-gup_benchmark-use-pin_user_pages-for-foll_longterm-flag +++ a/mm/gup_benchmark.c @@ -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 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 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 i 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(unsigne 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(unsigne 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 f 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; --- a/tools/testing/selftests/vm/gup_benchmark.c~mm-gup_benchmark-use-pin_user_pages-for-foll_longterm-flag +++ a/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; _
