kernel/linux.git/tools/testing/selftests/vm/gup_benchmark.c, branch linux-5.3.y

mm/gup_benchmark: fix MAP_HUGETLB case

2019-12-04T21:33:49+00:00

[ Upstream commit 64801d19eba156170340c76f70ade743defcb8ce ] The MAP_HUGETLB ("-H" option) of gup_benchmark fails: $ sudo ./gup_benchmark -H mmap: Invalid argument This is because gup_benchmark.c is passing in a file descriptor to mmap(), but the fd came from opening up the /dev/zero file. This confuses the mmap syscall implementation, which thinks that, if the caller did not specify MAP_ANONYMOUS, then the file must be a huge page file. So it attempts to verify that the file really is a huge page file, as you can see here: ksys_mmap_pgoff() { if (!(flags & MAP_ANONYMOUS)) { retval = -EINVAL; if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file))) goto out_fput; /* THIS IS WHERE WE END UP */ else if (flags & MAP_HUGETLB) { ...proceed normally, /dev/zero is ok here... ...and of course is_file_hugepages() returns "false" for the /dev/zero file. The problem is that the user space program, gup_benchmark.c, really just wants anonymous memory here. The simplest way to get that is to pass MAP_ANONYMOUS whenever MAP_HUGETLB is specified, so that's what this patch does. Link: http://lkml.kernel.org/r/20191021212435.398153-2-jhubbard@nvidia.com Signed-off-by: John Hubbard Reviewed-by: Andrew Morton Reviewed-by: Jérôme Glisse Cc: Keith Busch Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

selftests/vm/gup_benchmark.c: match gup struct to kernel

2019-01-15T20:48:24+00:00

An expansion field was added to the kernel copy of this structure for future use. See mm/gup_benchmark.c. Add the same expansion field here, so that the IOCTL command decodes correctly. Otherwise, it fails with EINVAL. Signed-off-by: Alison Schofield Acked-by: Kirill A. Shutemov Signed-off-by: Shuah Khan

tools/testing/selftests/vm/gup_benchmark.c: add MAP_HUGETLB option

2018-10-26T23:38:15+00:00

Add a new option '-H' to the gup benchmark to help understand how hugetlb mapping pages compare with the default. Link: http://lkml.kernel.org/r/20181010195605.10689-6-keith.busch@intel.com Signed-off-by: Keith Busch Reviewed-by: Andrew Morton Cc: Kirill Shutemov Cc: Dave Hansen Cc: Dan Williams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

tools/testing/selftests/vm/gup_benchmark.c: add MAP_SHARED option

2018-10-26T23:38:15+00:00

Add a new benchmark option, -S, to request MAP_SHARED. This can be used to compare with MAP_PRIVATE, or for files that require this option, like dax. Link: http://lkml.kernel.org/r/20181010195605.10689-5-keith.busch@intel.com Signed-off-by: Keith Busch Reviewed-by: Andrew Morton Cc: Kirill Shutemov Cc: Dave Hansen Cc: Dan Williams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

tools/testing/selftests/vm/gup_benchmark.c: allow user specified file

2018-10-26T23:38:15+00:00

Allow a user to specify a file to map by adding a new option, '-f', providing a means to test various file backings. If not specified, the benchmark will use a private mapping of /dev/zero, which produces an anonymous mapping as before. [akpm@linux-foundation.org: avoid using comma operator] Link: http://lkml.kernel.org/r/20181010195605.10689-4-keith.busch@intel.com Signed-off-by: Keith Busch Reviewed-by: Andrew Morton Cc: Kirill Shutemov Cc: Dave Hansen Cc: Dan Williams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

tools/testing/selftests/vm/gup_benchmark.c: fix 'write' flag usage

2018-10-26T23:38:15+00:00

If the '-w' parameter was provided, the benchmark would exit due to a mssing 'break'. Link: http://lkml.kernel.org/r/20181010195605.10689-3-keith.busch@intel.com Signed-off-by: Keith Busch Acked-by: Kirill A. Shutemov Reviewed-by: Andrew Morton Cc: Dave Hansen Cc: Dan Williams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/gup_benchmark.c: add additional pinning methods

2018-10-26T23:38:15+00:00

Provide new gup benchmark ioctl commands to run different user page pinning methods, get_user_pages_longterm() and get_user_pages(), in addition to the existing get_user_pages_fast(). Link: http://lkml.kernel.org/r/20181010195605.10689-2-keith.busch@intel.com Signed-off-by: Keith Busch Acked-by: Kirill A. Shutemov Reviewed-by: Andrew Morton Cc: Dave Hansen Cc: Dan Williams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/gup_benchmark.c: time put_page()

2018-10-26T23:38:15+00:00

We'd like to measure time to unpin user pages, so this adds a second benchmark timer on put_page, separate from get_page. Adding the field breaks this ioctl ABI, but should be okay since this an in-tree kernel selftest. [akpm@linux-foundation.org: add expansion to struct gup_benchmark for future use] Link: http://lkml.kernel.org/r/20181010195605.10689-1-keith.busch@intel.com Signed-off-by: Keith Busch Acked-by: Kirill A. Shutemov Reviewed-by: Andrew Morton Cc: Dave Hansen Cc: Dan Williams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: add infrastructure for get_user_pages_fast() benchmarking

2017-11-18T00:10:04+00:00

Performance of get_user_pages_fast() is critical for some workloads, but it's tricky to test it directly. This patch provides /sys/kernel/debug/gup_benchmark that helps with testing performance of it. See tools/testing/selftests/vm/gup_benchmark.c for userspace counterpart. Link: http://lkml.kernel.org/r/20170908215603.9189-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Cc: Shuah Khan Cc: Ingo Molnar Cc: Thorsten Leemhuis Cc: Jonathan Corbet Cc: Huang Ying Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds