[PATCH v3 00/10] iov_iter: kunit: Cleanup, abstraction and more tests

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David Howells

22 Sep 2023 22 Sep '23

11:30 a.m.

Hi Jens,

Can you consider taking this through the block tree?

These patches make some changes to the kunit tests previously added for iov_iter testing, in particular adding testing of UBUF/IOVEC iterators and some benchmarking:

(1) Clean up a couple of checkpatch style complaints.

(2) Consolidate some repeated bits of code into helper functions and use the same struct to represent straight offset/address ranges and partial page lists.

(3) Add a function to set up a userspace VM, attach the VM to the kunit testing thread, create an anonymous file, stuff some pages into the file and map the file into the VM to act as a buffer that can be used with UBUF/IOVEC iterators.

I map an anonymous file with pages attached rather than using MAP_ANON so that I can check the pages obtained from iov_iter_extract_pages() without worrying about them changing due to swap, migrate, etc..

[?] Is this the best way to do things? Mirroring execve, it requires a number of extra core symbols to be exported. Should this be done in the core code?

(4) Add tests for copying into and out of UBUF and IOVEC iterators.

(5) Add tests for extracting pages from UBUF and IOVEC iterators.

(6) Add tests to benchmark copying 256MiB to UBUF, IOVEC, KVEC, BVEC and XARRAY iterators.

(7) Add a test to bencmark copying 256MiB from an xarray that gets decanted into 256-page BVEC iterators to model batching from the pagecache.

(8) Add a test to benchmark copying 256MiB through dynamically allocated 256-page bvecs to simulate bio construction.

Example benchmarks output:

iov_kunit_benchmark_ubuf: avg 4474 uS, stddev 1340 uS iov_kunit_benchmark_iovec: avg 6619 uS, stddev 23 uS iov_kunit_benchmark_kvec: avg 2672 uS, stddev 14 uS iov_kunit_benchmark_bvec: avg 3189 uS, stddev 19 uS iov_kunit_benchmark_bvec_split: avg 3403 uS, stddev 8 uS iov_kunit_benchmark_xarray: avg 3709 uS, stddev 7 uS

I've pushed the patches here also:

https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h...

David

Changes ======= ver #3) - #include <linux/personality.h> to get READ_IMPLIES_EXEC. - Add a test to benchmark decanting an xarray into bio_vecs.

ver #2) - Use MAP_ANON to make the user buffer if we don't want a list of pages. - KUNIT_ASSERT_NOT_ERR_OR_NULL() doesn't like __user pointers as the condition, so cast. - Make the UBUF benchmark loop, doing an iterator per page so that the overhead from the iterator code is not negligible. - Make the KVEC benchmark use an iovec per page so that the iteration is not not negligible. - Switch the benchmarking to use copy_from_iter() so that only a single page is needed in the userspace buffer (as it can be shared R/O), not 256MiB's worth.

Link: https://lore.kernel.org/r/20230914221526.3153402-1-dhowells@redhat.com/ # v1 Link: https://lore.kernel.org/r/20230920130400.203330-1-dhowells@redhat.com/ # v2

David Howells (10): iov_iter: Fix some checkpatch complaints in kunit tests iov_iter: Consolidate some of the repeated code into helpers iov_iter: Consolidate the test vector struct in the kunit tests iov_iter: Consolidate bvec pattern checking iov_iter: Create a function to prepare userspace VM for UBUF/IOVEC tests iov_iter: Add copy kunit tests for ITER_UBUF and ITER_IOVEC iov_iter: Add extract kunit tests for ITER_UBUF and ITER_IOVEC iov_iter: Add benchmarking kunit tests iov_iter: Add kunit to benchmark decanting of xarray to bvec iov_iter: Add benchmarking kunit tests for UBUF/IOVEC

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David Howells

22 Sep 22 Sep

11:30 a.m.

New subject: [PATCH v3 01/10] iov_iter: Fix some checkpatch complaints in kunit tests

Fix some checkpatch complaints in the new iov_iter kunit tests:

(1) Some lines had eight spaces instead of a tab at the start.

(2) Checkpatch doesn't like (void*)(unsigned long)0xnnnnnULL, so switch to using POISON_POINTER_DELTA plus an offset instead.

Reported-by: Johannes Thumshirn Johannes.Thumshirn@wdc.com Signed-off-by: David Howells dhowells@redhat.com cc: Christoph Hellwig hch@lst.de cc: Christian Brauner brauner@kernel.org cc: Jens Axboe axboe@kernel.dk cc: Al Viro viro@zeniv.linux.org.uk cc: David Hildenbrand david@redhat.com cc: John Hubbard jhubbard@nvidia.com cc: Brendan Higgins brendanhiggins@google.com cc: David Gow davidgow@google.com cc: linux-kselftest@vger.kernel.org cc: kunit-dev@googlegroups.com cc: linux-mm@kvack.org cc: linux-fsdevel@vger.kernel.org --- lib/kunit_iov_iter.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c index 859b67c4d697..4a6c0efd33f5 100644 --- a/lib/kunit_iov_iter.c +++ b/lib/kunit_iov_iter.c @@ -53,7 +53,7 @@ static void *__init iov_kunit_create_buffer(struct kunit *test, void *buffer;

pages = kunit_kcalloc(test, npages, sizeof(struct page *), GFP_KERNEL); - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pages); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pages); *ppages = pages;

got = alloc_pages_bulk_array(GFP_KERNEL, npages, pages); @@ -63,7 +63,7 @@ static void *__init iov_kunit_create_buffer(struct kunit *test, }

buffer = vmap(pages, npages, VM_MAP | VM_MAP_PUT_PAGES, PAGE_KERNEL); - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buffer); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buffer);

kunit_add_action_or_reset(test, iov_kunit_unmap, buffer); return buffer; @@ -548,7 +548,7 @@ static void __init iov_kunit_extract_pages_kvec(struct kunit *test) size_t offset0 = LONG_MAX;

for (i = 0; i < ARRAY_SIZE(pagelist); i++) - pagelist[i] = (void *)(unsigned long)0xaa55aa55aa55aa55ULL; + pagelist[i] = (void *)POISON_POINTER_DELTA + 0x5a;

len = iov_iter_extract_pages(&iter, &pages, 100 * 1024, ARRAY_SIZE(pagelist), 0, &offset0); @@ -626,7 +626,7 @@ static void __init iov_kunit_extract_pages_bvec(struct kunit *test) size_t offset0 = LONG_MAX;

for (i = 0; i < ARRAY_SIZE(pagelist); i++) - pagelist[i] = (void *)(unsigned long)0xaa55aa55aa55aa55ULL; + pagelist[i] = (void *)POISON_POINTER_DELTA + 0x5a;

len = iov_iter_extract_pages(&iter, &pages, 100 * 1024, ARRAY_SIZE(pagelist), 0, &offset0); @@ -709,7 +709,7 @@ static void __init iov_kunit_extract_pages_xarray(struct kunit *test) size_t offset0 = LONG_MAX;

for (i = 0; i < ARRAY_SIZE(pagelist); i++) - pagelist[i] = (void *)(unsigned long)0xaa55aa55aa55aa55ULL; + pagelist[i] = (void *)POISON_POINTER_DELTA + 0x5a;

len = iov_iter_extract_pages(&iter, &pages, 100 * 1024, ARRAY_SIZE(pagelist), 0, &offset0);

David Howells

11:30 a.m.

New subject: [PATCH v3 02/10] iov_iter: Consolidate some of the repeated code into helpers

Consolidate some of the repeated code snippets into helper functions to reduce the line count.

Signed-off-by: David Howells dhowells@redhat.com cc: Christoph Hellwig hch@lst.de cc: Christian Brauner brauner@kernel.org cc: Jens Axboe axboe@kernel.dk cc: Al Viro viro@zeniv.linux.org.uk cc: David Hildenbrand david@redhat.com cc: John Hubbard jhubbard@nvidia.com cc: Brendan Higgins brendanhiggins@google.com cc: David Gow davidgow@google.com cc: linux-kselftest@vger.kernel.org cc: kunit-dev@googlegroups.com cc: linux-mm@kvack.org cc: linux-fsdevel@vger.kernel.org --- lib/kunit_iov_iter.c | 189 +++++++++++++++++++------------------------ 1 file changed, 84 insertions(+), 105 deletions(-)

diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c index 4a6c0efd33f5..ee586eb652b4 100644 --- a/lib/kunit_iov_iter.c +++ b/lib/kunit_iov_iter.c @@ -19,18 +19,18 @@ MODULE_AUTHOR("David Howells dhowells@redhat.com"); MODULE_LICENSE("GPL");

struct kvec_test_range { - int from, to; + int page, from, to; };

static const struct kvec_test_range kvec_test_ranges[] = { - { 0x00002, 0x00002 }, - { 0x00027, 0x03000 }, - { 0x05193, 0x18794 }, - { 0x20000, 0x20000 }, - { 0x20000, 0x24000 }, - { 0x24000, 0x27001 }, - { 0x29000, 0xffffb }, - { 0xffffd, 0xffffe }, + { 0, 0x00002, 0x00002 }, + { 0, 0x00027, 0x03000 }, + { 0, 0x05193, 0x18794 }, + { 0, 0x20000, 0x20000 }, + { 0, 0x20000, 0x24000 }, + { 0, 0x24000, 0x27001 }, + { 0, 0x29000, 0xffffb }, + { 0, 0xffffd, 0xffffe }, { -1 } };

@@ -69,6 +69,57 @@ static void *__init iov_kunit_create_buffer(struct kunit *test, return buffer; }

+/* + * Build the reference pattern in the scratch buffer that we expect to see in + * the iterator buffer (ie. the result of copy *to*). + */ +static void iov_kunit_build_to_reference_pattern(struct kunit *test, u8 *scratch, + size_t bufsize, + const struct kvec_test_range *pr) +{ + int i, patt = 0; + + memset(scratch, 0, bufsize); + for (; pr->page >= 0; pr++) + for (i = pr->from; i < pr->to; i++) + scratch[i] = pattern(patt++); +} + +/* + * Build the reference pattern in the iterator buffer that we expect to see in + * the scratch buffer (ie. the result of copy *from*). + */ +static void iov_kunit_build_from_reference_pattern(struct kunit *test, u8 *buffer, + size_t bufsize, + const struct kvec_test_range *pr) +{ + size_t i = 0, j; + + memset(buffer, 0, bufsize); + for (; pr->page >= 0; pr++) { + for (j = pr->from; j < pr->to; j++) { + buffer[i++] = pattern(j); + if (i >= bufsize) + return; + } + } +} + +/* + * Compare two kernel buffers to see that they're the same. + */ +static void iov_kunit_check_pattern(struct kunit *test, const u8 *buffer, + const u8 *scratch, size_t bufsize) +{ + size_t i; + + for (i = 0; i < bufsize; i++) { + KUNIT_EXPECT_EQ_MSG(test, buffer[i], scratch[i], "at i=%x", i); + if (buffer[i] != scratch[i]) + return; + } +} + static void __init iov_kunit_load_kvec(struct kunit *test, struct iov_iter *iter, int dir, struct kvec *kvec, unsigned int kvmax, @@ -79,7 +130,7 @@ static void __init iov_kunit_load_kvec(struct kunit *test, int i;

for (i = 0; i < kvmax; i++, pr++) { - if (pr->from < 0) + if (pr->page < 0) break; KUNIT_ASSERT_GE(test, pr->to, pr->from); KUNIT_ASSERT_LE(test, pr->to, bufsize); @@ -97,13 +148,12 @@ static void __init iov_kunit_load_kvec(struct kunit *test, */ static void __init iov_kunit_copy_to_kvec(struct kunit *test) { - const struct kvec_test_range *pr; struct iov_iter iter; struct page **spages, **bpages; struct kvec kvec[8]; u8 *scratch, *buffer; size_t bufsize, npages, size, copied; - int i, patt; + int i;

bufsize = 0x100000; npages = bufsize / PAGE_SIZE; @@ -125,20 +175,8 @@ static void __init iov_kunit_copy_to_kvec(struct kunit *test) KUNIT_EXPECT_EQ(test, iter.count, 0); KUNIT_EXPECT_EQ(test, iter.nr_segs, 0);

- /* Build the expected image in the scratch buffer. */ - patt = 0; - memset(scratch, 0, bufsize); - for (pr = kvec_test_ranges; pr->from >= 0; pr++) - for (i = pr->from; i < pr->to; i++) - scratch[i] = pattern(patt++); - - /* Compare the images */ - for (i = 0; i < bufsize; i++) { - KUNIT_EXPECT_EQ_MSG(test, buffer[i], scratch[i], "at i=%x", i); - if (buffer[i] != scratch[i]) - return; - } - + iov_kunit_build_to_reference_pattern(test, scratch, bufsize, kvec_test_ranges); + iov_kunit_check_pattern(test, buffer, scratch, bufsize); KUNIT_SUCCEED(); }

@@ -147,13 +185,12 @@ static void __init iov_kunit_copy_to_kvec(struct kunit *test) */ static void __init iov_kunit_copy_from_kvec(struct kunit *test) { - const struct kvec_test_range *pr; struct iov_iter iter; struct page **spages, **bpages; struct kvec kvec[8]; u8 *scratch, *buffer; size_t bufsize, npages, size, copied; - int i, j; + int i;

bufsize = 0x100000; npages = bufsize / PAGE_SIZE; @@ -175,25 +212,8 @@ static void __init iov_kunit_copy_from_kvec(struct kunit *test) KUNIT_EXPECT_EQ(test, iter.count, 0); KUNIT_EXPECT_EQ(test, iter.nr_segs, 0);

- /* Build the expected image in the main buffer. */ - i = 0; - memset(buffer, 0, bufsize); - for (pr = kvec_test_ranges; pr->from >= 0; pr++) { - for (j = pr->from; j < pr->to; j++) { - buffer[i++] = pattern(j); - if (i >= bufsize) - goto stop; - } - } -stop: - - /* Compare the images */ - for (i = 0; i < bufsize; i++) { - KUNIT_EXPECT_EQ_MSG(test, scratch[i], buffer[i], "at i=%x", i); - if (scratch[i] != buffer[i]) - return; - } - + iov_kunit_build_from_reference_pattern(test, buffer, bufsize, kvec_test_ranges); + iov_kunit_check_pattern(test, buffer, scratch, bufsize); KUNIT_SUCCEED(); }

@@ -210,7 +230,7 @@ static const struct bvec_test_range bvec_test_ranges[] = { { 5, 0x0000, 0x1000 }, { 6, 0x0000, 0x0ffb }, { 6, 0x0ffd, 0x0ffe }, - { -1, -1, -1 } + { -1 } };

static void __init iov_kunit_load_bvec(struct kunit *test, @@ -225,7 +245,7 @@ static void __init iov_kunit_load_bvec(struct kunit *test, int i;

for (i = 0; i < bvmax; i++, pr++) { - if (pr->from < 0) + if (pr->page < 0) break; KUNIT_ASSERT_LT(test, pr->page, npages); KUNIT_ASSERT_LT(test, pr->page * PAGE_SIZE, bufsize); @@ -288,20 +308,14 @@ static void __init iov_kunit_copy_to_bvec(struct kunit *test) b = 0; patt = 0; memset(scratch, 0, bufsize); - for (pr = bvec_test_ranges; pr->from >= 0; pr++, b++) { + for (pr = bvec_test_ranges; pr->page >= 0; pr++, b++) { u8 *p = scratch + pr->page * PAGE_SIZE;

for (i = pr->from; i < pr->to; i++) p[i] = pattern(patt++); }

- /* Compare the images */ - for (i = 0; i < bufsize; i++) { - KUNIT_EXPECT_EQ_MSG(test, buffer[i], scratch[i], "at i=%x", i); - if (buffer[i] != scratch[i]) - return; - } - + iov_kunit_check_pattern(test, buffer, scratch, bufsize); KUNIT_SUCCEED(); }

@@ -341,7 +355,7 @@ static void __init iov_kunit_copy_from_bvec(struct kunit *test) /* Build the expected image in the main buffer. */ i = 0; memset(buffer, 0, bufsize); - for (pr = bvec_test_ranges; pr->from >= 0; pr++) { + for (pr = bvec_test_ranges; pr->page >= 0; pr++) { size_t patt = pr->page * PAGE_SIZE;

for (j = pr->from; j < pr->to; j++) { @@ -352,13 +366,7 @@ static void __init iov_kunit_copy_from_bvec(struct kunit *test) } stop:

- /* Compare the images */ - for (i = 0; i < bufsize; i++) { - KUNIT_EXPECT_EQ_MSG(test, scratch[i], buffer[i], "at i=%x", i); - if (scratch[i] != buffer[i]) - return; - } - + iov_kunit_check_pattern(test, buffer, scratch, bufsize); KUNIT_SUCCEED(); }

@@ -409,7 +417,7 @@ static void __init iov_kunit_copy_to_xarray(struct kunit *test) struct page **spages, **bpages; u8 *scratch, *buffer; size_t bufsize, npages, size, copied; - int i, patt; + int i;

bufsize = 0x100000; npages = bufsize / PAGE_SIZE; @@ -426,7 +434,7 @@ static void __init iov_kunit_copy_to_xarray(struct kunit *test) iov_kunit_load_xarray(test, &iter, READ, xarray, bpages, npages);

i = 0; - for (pr = kvec_test_ranges; pr->from >= 0; pr++) { + for (pr = kvec_test_ranges; pr->page >= 0; pr++) { size = pr->to - pr->from; KUNIT_ASSERT_LE(test, pr->to, bufsize);

@@ -439,20 +447,8 @@ static void __init iov_kunit_copy_to_xarray(struct kunit *test) i += size; }

@@ -467,7 +463,7 @@ static void __init iov_kunit_copy_from_xarray(struct kunit *test) struct page **spages, **bpages; u8 *scratch, *buffer; size_t bufsize, npages, size, copied; - int i, j; + int i;

bufsize = 0x100000; npages = bufsize / PAGE_SIZE; @@ -484,7 +480,7 @@ static void __init iov_kunit_copy_from_xarray(struct kunit *test) iov_kunit_load_xarray(test, &iter, READ, xarray, bpages, npages);

i = 0; - for (pr = kvec_test_ranges; pr->from >= 0; pr++) { + for (pr = kvec_test_ranges; pr->page >= 0; pr++) { size = pr->to - pr->from; KUNIT_ASSERT_LE(test, pr->to, bufsize);

@@ -497,25 +493,8 @@ static void __init iov_kunit_copy_from_xarray(struct kunit *test) i += size; }

@@ -573,7 +552,7 @@ static void __init iov_kunit_extract_pages_kvec(struct kunit *test) while (from == pr->to) { pr++; from = pr->from; - if (from < 0) + if (pr->page < 0) goto stop; } ix = from / PAGE_SIZE; @@ -651,7 +630,7 @@ static void __init iov_kunit_extract_pages_bvec(struct kunit *test) while (from == pr->to) { pr++; from = pr->from; - if (from < 0) + if (pr->page < 0) goto stop; } ix = pr->page + from / PAGE_SIZE; @@ -698,7 +677,7 @@ static void __init iov_kunit_extract_pages_xarray(struct kunit *test) iov_kunit_create_buffer(test, &bpages, npages); iov_kunit_load_xarray(test, &iter, READ, xarray, bpages, npages);

- for (pr = kvec_test_ranges; pr->from >= 0; pr++) { + for (pr = kvec_test_ranges; pr->page >= 0; pr++) { from = pr->from; size = pr->to - from; KUNIT_ASSERT_LE(test, pr->to, bufsize);

David Howells

11:30 a.m.

New subject: [PATCH v3 03/10] iov_iter: Consolidate the test vector struct in the kunit tests

Consolidate the test vector struct in the kunit tests so that the bvec pattern check helpers can share with the kvec check helpers.

Signed-off-by: David Howells dhowells@redhat.com cc: Christoph Hellwig hch@lst.de cc: Christian Brauner brauner@kernel.org cc: Jens Axboe axboe@kernel.dk cc: Al Viro viro@zeniv.linux.org.uk cc: David Hildenbrand david@redhat.com cc: John Hubbard jhubbard@nvidia.com cc: Brendan Higgins brendanhiggins@google.com cc: David Gow davidgow@google.com cc: linux-kselftest@vger.kernel.org cc: kunit-dev@googlegroups.com cc: linux-mm@kvack.org cc: linux-fsdevel@vger.kernel.org --- lib/kunit_iov_iter.c | 90 ++++++++++++++++++++++++-------------------- 1 file changed, 50 insertions(+), 40 deletions(-)

diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c index ee586eb652b4..4925ca37cde6 100644 --- a/lib/kunit_iov_iter.c +++ b/lib/kunit_iov_iter.c @@ -18,22 +18,46 @@ MODULE_DESCRIPTION("iov_iter testing"); MODULE_AUTHOR("David Howells dhowells@redhat.com"); MODULE_LICENSE("GPL");

-struct kvec_test_range { +struct iov_kunit_range { int page, from, to; };

-static const struct kvec_test_range kvec_test_ranges[] = { - { 0, 0x00002, 0x00002 }, - { 0, 0x00027, 0x03000 }, - { 0, 0x05193, 0x18794 }, - { 0, 0x20000, 0x20000 }, - { 0, 0x20000, 0x24000 }, - { 0, 0x24000, 0x27001 }, - { 0, 0x29000, 0xffffb }, - { 0, 0xffffd, 0xffffe }, +/* + * Ranges that to use in tests where we have address/offset ranges to play + * with (ie. KVEC) or where we have a single blob that we can copy + * arbitrary chunks of (ie. XARRAY). + */ +static const struct iov_kunit_range kvec_test_ranges[] = { + { 0, 0x00002, 0x00002 }, /* Start with an empty range */ + { 0, 0x00027, 0x03000 }, /* Midpage to page end */ + { 0, 0x05193, 0x18794 }, /* Midpage to midpage */ + { 0, 0x20000, 0x20000 }, /* Empty range in the middle */ + { 0, 0x20000, 0x24000 }, /* Page start to page end */ + { 0, 0x24000, 0x27001 }, /* Page end to midpage */ + { 0, 0x29000, 0xffffb }, /* Page start to midpage */ + { 0, 0xffffd, 0xffffe }, /* Almost contig to last, ending in same page */ { -1 } };

+/* + * Ranges that to use in tests where we have a list of partial pages to + * play with (ie. BVEC). + */ +static const struct iov_kunit_range bvec_test_ranges[] = { + { 0, 0x0002, 0x0002 }, /* Start with an empty range */ + { 1, 0x0027, 0x0893 }, /* Random part of page */ + { 2, 0x0193, 0x0794 }, /* Random part of page */ + { 3, 0x0000, 0x1000 }, /* Full page */ + { 4, 0x0000, 0x1000 }, /* Full page logically contig to last */ + { 5, 0x0000, 0x1000 }, /* Full page logically contig to last */ + { 6, 0x0000, 0x0ffb }, /* Part page logically contig to last */ + { 6, 0x0ffd, 0x0ffe }, /* Part of prev page, but not quite contig */ + { -1 } +}; + +/* + * The pattern to fill with. + */ static inline u8 pattern(unsigned long x) { return x & 0xff; @@ -44,6 +68,9 @@ static void iov_kunit_unmap(void *data) vunmap(data); }

+/* + * Create a buffer out of some pages and return a vmap'd pointer to it. + */ static void *__init iov_kunit_create_buffer(struct kunit *test, struct page ***ppages, size_t npages) @@ -75,7 +102,7 @@ static void *__init iov_kunit_create_buffer(struct kunit *test, */ static void iov_kunit_build_to_reference_pattern(struct kunit *test, u8 *scratch, size_t bufsize, - const struct kvec_test_range *pr) + const struct iov_kunit_range *pr) { int i, patt = 0;

@@ -91,7 +118,7 @@ static void iov_kunit_build_to_reference_pattern(struct kunit *test, u8 *scratch */ static void iov_kunit_build_from_reference_pattern(struct kunit *test, u8 *buffer, size_t bufsize, - const struct kvec_test_range *pr) + const struct iov_kunit_range *pr) { size_t i = 0, j;

@@ -124,7 +151,7 @@ static void __init iov_kunit_load_kvec(struct kunit *test, struct iov_iter *iter, int dir, struct kvec *kvec, unsigned int kvmax, void *buffer, size_t bufsize, - const struct kvec_test_range *pr) + const struct iov_kunit_range *pr) { size_t size = 0; int i; @@ -217,28 +244,12 @@ static void __init iov_kunit_copy_from_kvec(struct kunit *test) KUNIT_SUCCEED(); }

-struct bvec_test_range { - int page, from, to; -}; - -static const struct bvec_test_range bvec_test_ranges[] = { - { 0, 0x0002, 0x0002 }, - { 1, 0x0027, 0x0893 }, - { 2, 0x0193, 0x0794 }, - { 3, 0x0000, 0x1000 }, - { 4, 0x0000, 0x1000 }, - { 5, 0x0000, 0x1000 }, - { 6, 0x0000, 0x0ffb }, - { 6, 0x0ffd, 0x0ffe }, - { -1 } -}; - static void __init iov_kunit_load_bvec(struct kunit *test, struct iov_iter *iter, int dir, struct bio_vec *bvec, unsigned int bvmax, struct page **pages, size_t npages, size_t bufsize, - const struct bvec_test_range *pr) + const struct iov_kunit_range *pr) { struct page *can_merge = NULL, *page; size_t size = 0; @@ -276,13 +287,13 @@ static void __init iov_kunit_load_bvec(struct kunit *test, */ static void __init iov_kunit_copy_to_bvec(struct kunit *test) { - const struct bvec_test_range *pr; + const struct iov_kunit_range *pr; struct iov_iter iter; struct bio_vec bvec[8]; struct page **spages, **bpages; u8 *scratch, *buffer; size_t bufsize, npages, size, copied; - int i, b, patt; + int i, patt;

bufsize = 0x100000; npages = bufsize / PAGE_SIZE; @@ -305,10 +316,9 @@ static void __init iov_kunit_copy_to_bvec(struct kunit *test) KUNIT_EXPECT_EQ(test, iter.nr_segs, 0);

/* Build the expected image in the scratch buffer. */ - b = 0; patt = 0; memset(scratch, 0, bufsize); - for (pr = bvec_test_ranges; pr->page >= 0; pr++, b++) { + for (pr = bvec_test_ranges; pr->page >= 0; pr++) { u8 *p = scratch + pr->page * PAGE_SIZE;

for (i = pr->from; i < pr->to; i++) @@ -324,7 +334,7 @@ static void __init iov_kunit_copy_to_bvec(struct kunit *test) */ static void __init iov_kunit_copy_from_bvec(struct kunit *test) { - const struct bvec_test_range *pr; + const struct iov_kunit_range *pr; struct iov_iter iter; struct bio_vec bvec[8]; struct page **spages, **bpages; @@ -411,7 +421,7 @@ static struct xarray *iov_kunit_create_xarray(struct kunit *test) */ static void __init iov_kunit_copy_to_xarray(struct kunit *test) { - const struct kvec_test_range *pr; + const struct iov_kunit_range *pr; struct iov_iter iter; struct xarray *xarray; struct page **spages, **bpages; @@ -457,7 +467,7 @@ static void __init iov_kunit_copy_to_xarray(struct kunit *test) */ static void __init iov_kunit_copy_from_xarray(struct kunit *test) { - const struct kvec_test_range *pr; + const struct iov_kunit_range *pr; struct iov_iter iter; struct xarray *xarray; struct page **spages, **bpages; @@ -503,7 +513,7 @@ static void __init iov_kunit_copy_from_xarray(struct kunit *test) */ static void __init iov_kunit_extract_pages_kvec(struct kunit *test) { - const struct kvec_test_range *pr; + const struct iov_kunit_range *pr; struct iov_iter iter; struct page **bpages, *pagelist[8], **pages = pagelist; struct kvec kvec[8]; @@ -583,7 +593,7 @@ static void __init iov_kunit_extract_pages_kvec(struct kunit *test) */ static void __init iov_kunit_extract_pages_bvec(struct kunit *test) { - const struct bvec_test_range *pr; + const struct iov_kunit_range *pr; struct iov_iter iter; struct page **bpages, *pagelist[8], **pages = pagelist; struct bio_vec bvec[8]; @@ -661,7 +671,7 @@ static void __init iov_kunit_extract_pages_bvec(struct kunit *test) */ static void __init iov_kunit_extract_pages_xarray(struct kunit *test) { - const struct kvec_test_range *pr; + const struct iov_kunit_range *pr; struct iov_iter iter; struct xarray *xarray; struct page **bpages, *pagelist[8], **pages = pagelist;

David Howells

11:30 a.m.

New subject: [PATCH v3 04/10] iov_iter: Consolidate bvec pattern checking

Make the BVEC-testing functions use the consolidated pattern checking functions to reduce the amount of duplicated code.

Signed-off-by: David Howells dhowells@redhat.com cc: Christoph Hellwig hch@lst.de cc: Christian Brauner brauner@kernel.org cc: Jens Axboe axboe@kernel.dk cc: Al Viro viro@zeniv.linux.org.uk cc: David Hildenbrand david@redhat.com cc: John Hubbard jhubbard@nvidia.com cc: Brendan Higgins brendanhiggins@google.com cc: David Gow davidgow@google.com cc: linux-kselftest@vger.kernel.org cc: kunit-dev@googlegroups.com cc: linux-mm@kvack.org cc: linux-fsdevel@vger.kernel.org --- lib/kunit_iov_iter.c | 42 +++++++++++------------------------------- 1 file changed, 11 insertions(+), 31 deletions(-)

diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c index 4925ca37cde6..eb86371b67d0 100644 --- a/lib/kunit_iov_iter.c +++ b/lib/kunit_iov_iter.c @@ -107,9 +107,11 @@ static void iov_kunit_build_to_reference_pattern(struct kunit *test, u8 *scratch int i, patt = 0;

memset(scratch, 0, bufsize); - for (; pr->page >= 0; pr++) + for (; pr->page >= 0; pr++) { + u8 *p = scratch + pr->page * PAGE_SIZE; for (i = pr->from; i < pr->to; i++) - scratch[i] = pattern(patt++); + p[i] = pattern(patt++); + } }

/* @@ -124,8 +126,10 @@ static void iov_kunit_build_from_reference_pattern(struct kunit *test, u8 *buffe

memset(buffer, 0, bufsize); for (; pr->page >= 0; pr++) { + size_t patt = pr->page * PAGE_SIZE; + for (j = pr->from; j < pr->to; j++) { - buffer[i++] = pattern(j); + buffer[i++] = pattern(patt + j); if (i >= bufsize) return; } @@ -287,13 +291,12 @@ static void __init iov_kunit_load_bvec(struct kunit *test, */ static void __init iov_kunit_copy_to_bvec(struct kunit *test) { - const struct iov_kunit_range *pr; struct iov_iter iter; struct bio_vec bvec[8]; struct page **spages, **bpages; u8 *scratch, *buffer; size_t bufsize, npages, size, copied; - int i, patt; + int i;

bufsize = 0x100000; npages = bufsize / PAGE_SIZE; @@ -315,16 +318,7 @@ static void __init iov_kunit_copy_to_bvec(struct kunit *test) KUNIT_EXPECT_EQ(test, iter.count, 0); KUNIT_EXPECT_EQ(test, iter.nr_segs, 0);

- /* Build the expected image in the scratch buffer. */ - patt = 0; - memset(scratch, 0, bufsize); - for (pr = bvec_test_ranges; pr->page >= 0; pr++) { - u8 *p = scratch + pr->page * PAGE_SIZE; - - for (i = pr->from; i < pr->to; i++) - p[i] = pattern(patt++); - } - + iov_kunit_build_to_reference_pattern(test, scratch, bufsize, bvec_test_ranges); iov_kunit_check_pattern(test, buffer, scratch, bufsize); KUNIT_SUCCEED(); } @@ -334,13 +328,12 @@ static void __init iov_kunit_copy_to_bvec(struct kunit *test) */ static void __init iov_kunit_copy_from_bvec(struct kunit *test) { - const struct iov_kunit_range *pr; struct iov_iter iter; struct bio_vec bvec[8]; struct page **spages, **bpages; u8 *scratch, *buffer; size_t bufsize, npages, size, copied; - int i, j; + int i;

bufsize = 0x100000; npages = bufsize / PAGE_SIZE; @@ -362,20 +355,7 @@ static void __init iov_kunit_copy_from_bvec(struct kunit *test) KUNIT_EXPECT_EQ(test, iter.count, 0); KUNIT_EXPECT_EQ(test, iter.nr_segs, 0);

- /* Build the expected image in the main buffer. */ - i = 0; - memset(buffer, 0, bufsize); - for (pr = bvec_test_ranges; pr->page >= 0; pr++) { - size_t patt = pr->page * PAGE_SIZE; - - for (j = pr->from; j < pr->to; j++) { - buffer[i++] = pattern(patt + j); - if (i >= bufsize) - goto stop; - } - } -stop: - + iov_kunit_build_from_reference_pattern(test, buffer, bufsize, bvec_test_ranges); iov_kunit_check_pattern(test, buffer, scratch, bufsize); KUNIT_SUCCEED(); }

David Howells

11:30 a.m.

New subject: [PATCH v3 05/10] iov_iter: Create a function to prepare userspace VM for UBUF/IOVEC tests

Create a function to set up a userspace VM for the kunit testing thread and set up a buffer within it such that ITER_UBUF and ITER_IOVEC tests can be performed.

Note that this requires current->mm to point to a sufficiently set up mm_struct. This is done by partially mirroring what execve does.

The following steps are performed:

(1) Allocate an mm_struct and pick an arch layout (required to set mm->get_unmapped_area).

(2) Create an empty "stack" VMA so that the VMA maple tree is set up and won't cause a crash in the maple tree code later. We don't actually care about the stack as we're not going to actually execute userspace.

(3) Create an anon file and attach a bunch of folios to it so that the requested number of pages are accessible.

(4) Make the kthread use the mm. This must be done before mmap is called.

(5) Shared-mmap the anon file into the allocated mm_struct.

This requires access to otherwise unexported core symbols: mm_alloc(), vm_area_alloc(), insert_vm_struct() arch_pick_mmap_layout() and anon_inode_getfile_secure(), which I've exported _GPL.

[?] Would it be better if this were done in core and not in a module?

Signed-off-by: David Howells dhowells@redhat.com cc: Andrew Morton akpm@linux-foundation.org cc: Christoph Hellwig hch@lst.de cc: Christian Brauner brauner@kernel.org cc: Jens Axboe axboe@kernel.dk cc: Al Viro viro@zeniv.linux.org.uk cc: Matthew Wilcox willy@infradead.org cc: David Hildenbrand david@redhat.com cc: John Hubbard jhubbard@nvidia.com cc: Brendan Higgins brendanhiggins@google.com cc: David Gow davidgow@google.com cc: Huacai Chen chenhuacai@kernel.org cc: WANG Xuerui kernel@xen0n.name cc: Heiko Carstens hca@linux.ibm.com cc: Vasily Gorbik gor@linux.ibm.com cc: Alexander Gordeev agordeev@linux.ibm.com cc: Christian Borntraeger borntraeger@linux.ibm.com cc: Sven Schnelle svens@linux.ibm.com cc: linux-mm@kvack.org cc: loongarch@lists.linux.dev cc: linux-s390@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-kselftest@vger.kernel.org cc: kunit-dev@googlegroups.com --- arch/s390/kernel/vdso.c | 1 + fs/anon_inodes.c | 1 + kernel/fork.c | 2 + lib/kunit_iov_iter.c | 143 ++++++++++++++++++++++++++++++++++++++++ mm/mmap.c | 1 + mm/util.c | 3 + 6 files changed, 151 insertions(+)

diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c index bbaefd84f15e..6849eac59129 100644 --- a/arch/s390/kernel/vdso.c +++ b/arch/s390/kernel/vdso.c @@ -223,6 +223,7 @@ unsigned long vdso_size(void) size += vdso64_end - vdso64_start; return PAGE_ALIGN(size); } +EXPORT_SYMBOL_GPL(vdso_size);

int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) { diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c index 24192a7667ed..4190336180ee 100644 --- a/fs/anon_inodes.c +++ b/fs/anon_inodes.c @@ -176,6 +176,7 @@ struct file *anon_inode_getfile_secure(const char *name, return __anon_inode_getfile(name, fops, priv, flags, context_inode, true); } +EXPORT_SYMBOL_GPL(anon_inode_getfile_secure);

static int __anon_inode_getfd(const char *name, const struct file_operations *fops, diff --git a/kernel/fork.c b/kernel/fork.c index 3b6d20dfb9a8..9ab604574400 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -494,6 +494,7 @@ struct vm_area_struct *vm_area_alloc(struct mm_struct *mm)

return vma; } +EXPORT_SYMBOL_GPL(vm_area_alloc);

struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) { @@ -1337,6 +1338,7 @@ struct mm_struct *mm_alloc(void) memset(mm, 0, sizeof(*mm)); return mm_init(mm, current, current_user_ns()); } +EXPORT_SYMBOL_GPL(mm_alloc);

static inline void __mmput(struct mm_struct *mm) { diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c index eb86371b67d0..63e4dd1e7c1b 100644 --- a/lib/kunit_iov_iter.c +++ b/lib/kunit_iov_iter.c @@ -10,6 +10,13 @@ #include <linux/module.h> #include <linux/vmalloc.h> #include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/mman.h> +#include <linux/file.h> +#include <linux/kthread.h> +#include <linux/anon_inodes.h> +#include <linux/writeback.h> +#include <linux/personality.h> #include <linux/uio.h> #include <linux/bvec.h> #include <kunit/test.h> @@ -68,6 +75,20 @@ static void iov_kunit_unmap(void *data) vunmap(data); }

+static void iov_kunit_mmdrop(void *data) +{ + struct mm_struct *mm = data; + + if (current->mm == mm) + kthread_unuse_mm(mm); + mmdrop(mm); +} + +static void iov_kunit_fput(void *data) +{ + fput(data); +} + /* * Create a buffer out of some pages and return a vmap'd pointer to it. */ @@ -151,6 +172,128 @@ static void iov_kunit_check_pattern(struct kunit *test, const u8 *buffer, } }

+static const struct file_operations iov_kunit_user_file_fops = { + .mmap = generic_file_mmap, +}; + +static int iov_kunit_user_file_read_folio(struct file *file, struct folio *folio) +{ + folio_mark_uptodate(folio); + folio_unlock(folio); + return 0; +} + +static const struct address_space_operations iov_kunit_user_file_aops = { + .read_folio = iov_kunit_user_file_read_folio, + .dirty_folio = filemap_dirty_folio, +}; + +/* + * Create an anonymous file and attach a bunch of pages to it. We can then use + * this in mmap() and check the pages against it when doing extraction tests. + */ +static struct file *iov_kunit_create_file(struct kunit *test, size_t npages, + struct page ***ppages) +{ + struct folio *folio; + struct file *file; + struct page **pages = NULL; + size_t i; + + if (ppages) { + pages = kunit_kcalloc(test, npages, sizeof(struct page *), GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pages); + *ppages = pages; + } + + file = anon_inode_getfile_secure("kunit-iov-test", + &iov_kunit_user_file_fops, + NULL, O_RDWR, NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, file); + kunit_add_action_or_reset(test, iov_kunit_fput, file); + file->f_mapping->a_ops = &iov_kunit_user_file_aops; + + i_size_write(file_inode(file), npages * PAGE_SIZE); + for (i = 0; i < npages; i++) { + folio = filemap_grab_folio(file->f_mapping, i); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, folio); + if (pages) + *pages++ = folio_page(folio, 0); + folio_unlock(folio); + folio_put(folio); + } + + return file; +} + +/* + * Attach a userspace buffer to a kernel thread by adding an mm_struct to it + * and mmapping the buffer. If the caller requires a list of pages for + * checking, then an anon_inode file is created, populated with pages and + * mmapped otherwise an anonymous mapping is used. + */ +static u8 __user *__init iov_kunit_create_user_buf(struct kunit *test, + size_t npages, + struct page ***ppages) +{ + struct rlimit rlim_stack = { + .rlim_cur = LONG_MAX, + .rlim_max = LONG_MAX, + }; + struct vm_area_struct *vma; + struct mm_struct *mm; + struct file *file; + u8 __user *buffer; + int ret; + + KUNIT_ASSERT_NULL(test, current->mm); + + mm = mm_alloc(); + KUNIT_ASSERT_NOT_NULL(test, mm); + kunit_add_action_or_reset(test, iov_kunit_mmdrop, mm); + arch_pick_mmap_layout(mm, &rlim_stack); + + vma = vm_area_alloc(mm); + KUNIT_ASSERT_NOT_NULL(test, vma); + vma_set_anonymous(vma); + + /* + * Place the stack at the largest stack address the architecture + * supports. Later, we'll move this to an appropriate place. We don't + * use STACK_TOP because that can depend on attributes which aren't + * configured yet. + */ + vma->vm_end = STACK_TOP_MAX; + vma->vm_start = vma->vm_end - PAGE_SIZE; + vm_flags_init(vma, VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP); + vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); + + ret = insert_vm_struct(mm, vma); + KUNIT_ASSERT_EQ(test, ret, 0); + + mm->stack_vm = mm->total_vm = 1; + + /* + * If we want the pages, attach the pages to a file to prevent swap + * interfering, otherwise use an anonymous mapping. + */ + if (ppages) { + file = iov_kunit_create_file(test, npages, ppages); + + kthread_use_mm(mm); + buffer = (u8 __user *)vm_mmap(file, 0, PAGE_SIZE * npages, + PROT_READ | PROT_WRITE, + MAP_SHARED, 0); + } else { + kthread_use_mm(mm); + buffer = (u8 __user *)vm_mmap(NULL, 0, PAGE_SIZE * npages, + PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, 0); + } + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, (void __force *)buffer); + return buffer; +} + static void __init iov_kunit_load_kvec(struct kunit *test, struct iov_iter *iter, int dir, struct kvec *kvec, unsigned int kvmax, diff --git a/mm/mmap.c b/mm/mmap.c index b56a7f0c9f85..2ea4a98a2cab 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -3284,6 +3284,7 @@ int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)

return 0; } +EXPORT_SYMBOL_GPL(insert_vm_struct);

/* * Copy the vma structure to a new location in the same mm, diff --git a/mm/util.c b/mm/util.c index 8cbbfd3a3d59..09895358f067 100644 --- a/mm/util.c +++ b/mm/util.c @@ -455,6 +455,9 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) mm->get_unmapped_area = arch_get_unmapped_area; } #endif +#ifdef CONFIG_MMU +EXPORT_SYMBOL_GPL(arch_pick_mmap_layout); +#endif

/** * __account_locked_vm - account locked pages to an mm's locked_vm

David Howells

11:30 a.m.

New subject: [PATCH v3 06/10] iov_iter: Add copy kunit tests for ITER_UBUF and ITER_IOVEC

Add copy kunit tests for ITER_UBUF- and ITER_IOVEC-type iterators. This attaches a userspace VM with a mapped file in it temporarily to the test thread.

diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c index 63e4dd1e7c1b..34f0d82674ee 100644 --- a/lib/kunit_iov_iter.c +++ b/lib/kunit_iov_iter.c @@ -117,6 +117,23 @@ static void *__init iov_kunit_create_buffer(struct kunit *test, return buffer; }

+/* + * Fill a user buffer with a recognisable pattern. + */ +static void iov_kunit_fill_user_buf(struct kunit *test, + u8 __user *buffer, size_t bufsize) +{ + size_t i; + int err; + + for (i = 0; i < bufsize; i++) { + err = put_user(pattern(i), &buffer[i]); + KUNIT_EXPECT_EQ(test, err, 0); + if (test->status == KUNIT_FAILURE) + return; + } +} + /* * Build the reference pattern in the scratch buffer that we expect to see in * the iterator buffer (ie. the result of copy *to*). @@ -172,6 +189,25 @@ static void iov_kunit_check_pattern(struct kunit *test, const u8 *buffer, } }

+/* + * Compare a user and a scratch buffer to see that they're the same. + */ +static void iov_kunit_check_user_pattern(struct kunit *test, const u8 __user *buffer, + const u8 *scratch, size_t bufsize) +{ + size_t i; + int err; + u8 c; + + for (i = 0; i < bufsize; i++) { + err = get_user(c, &buffer[i]); + KUNIT_EXPECT_EQ(test, err, 0); + KUNIT_EXPECT_EQ_MSG(test, c, scratch[i], "at i=%x", i); + if (c != scratch[i]) + return; + } +} + static const struct file_operations iov_kunit_user_file_fops = { .mmap = generic_file_mmap, }; @@ -294,6 +330,202 @@ static u8 __user *__init iov_kunit_create_user_buf(struct kunit *test, return buffer; }

+/* + * Test copying to an ITER_UBUF-type iterator. + */ +static void __init iov_kunit_copy_to_ubuf(struct kunit *test) +{ + const struct iov_kunit_range *pr; + struct iov_iter iter; + struct page **spages; + u8 __user *buffer; + u8 *scratch; + ssize_t uncleared; + size_t bufsize, npages, size, copied; + int i; + + bufsize = 0x100000; + npages = bufsize / PAGE_SIZE; + + scratch = iov_kunit_create_buffer(test, &spages, npages); + for (i = 0; i < bufsize; i++) + scratch[i] = pattern(i); + + buffer = iov_kunit_create_user_buf(test, npages, NULL); + uncleared = clear_user(buffer, bufsize); + KUNIT_EXPECT_EQ(test, uncleared, 0); + if (uncleared) + return; + + i = 0; + for (pr = kvec_test_ranges; pr->page >= 0; pr++) { + size = pr->to - pr->from; + KUNIT_ASSERT_LE(test, pr->to, bufsize); + + iov_iter_ubuf(&iter, ITER_DEST, buffer + pr->from, size); + copied = copy_to_iter(scratch + i, size, &iter); + + KUNIT_EXPECT_EQ(test, copied, size); + KUNIT_EXPECT_EQ(test, iter.count, 0); + KUNIT_EXPECT_EQ(test, iter.iov_offset, size); + if (test->status == KUNIT_FAILURE) + break; + i += size; + } + + iov_kunit_build_to_reference_pattern(test, scratch, bufsize, kvec_test_ranges); + iov_kunit_check_user_pattern(test, buffer, scratch, bufsize); + KUNIT_SUCCEED(); +} + +/* + * Test copying from an ITER_UBUF-type iterator. + */ +static void __init iov_kunit_copy_from_ubuf(struct kunit *test) +{ + const struct iov_kunit_range *pr; + struct iov_iter iter; + struct page **spages; + u8 __user *buffer; + u8 *scratch, *reference; + size_t bufsize, npages, size, copied; + int i; + + bufsize = 0x100000; + npages = bufsize / PAGE_SIZE; + + buffer = iov_kunit_create_user_buf(test, npages, NULL); + iov_kunit_fill_user_buf(test, buffer, bufsize); + + scratch = iov_kunit_create_buffer(test, &spages, npages); + memset(scratch, 0, bufsize); + + reference = iov_kunit_create_buffer(test, &spages, npages); + + i = 0; + for (pr = kvec_test_ranges; pr->page >= 0; pr++) { + size = pr->to - pr->from; + KUNIT_ASSERT_LE(test, pr->to, bufsize); + + iov_iter_ubuf(&iter, ITER_SOURCE, buffer + pr->from, size); + copied = copy_from_iter(scratch + i, size, &iter); + + KUNIT_EXPECT_EQ(test, copied, size); + KUNIT_EXPECT_EQ(test, iter.count, 0); + KUNIT_EXPECT_EQ(test, iter.iov_offset, size); + if (test->status == KUNIT_FAILURE) + break; + i += size; + } + + iov_kunit_build_from_reference_pattern(test, reference, bufsize, kvec_test_ranges); + iov_kunit_check_pattern(test, scratch, reference, bufsize); + KUNIT_SUCCEED(); +} + +static void __init iov_kunit_load_iovec(struct kunit *test, + struct iov_iter *iter, int dir, + struct iovec *iov, unsigned int iovmax, + u8 __user *buffer, size_t bufsize, + const struct iov_kunit_range *pr) +{ + size_t size = 0; + int i; + + for (i = 0; i < iovmax; i++, pr++) { + if (pr->page < 0) + break; + KUNIT_ASSERT_GE(test, pr->to, pr->from); + KUNIT_ASSERT_LE(test, pr->to, bufsize); + iov[i].iov_base = buffer + pr->from; + iov[i].iov_len = pr->to - pr->from; + size += pr->to - pr->from; + } + KUNIT_ASSERT_LE(test, size, bufsize); + + iov_iter_init(iter, dir, iov, i, size); +} + +/* + * Test copying to an ITER_IOVEC-type iterator. + */ +static void __init iov_kunit_copy_to_iovec(struct kunit *test) +{ + struct iov_iter iter; + struct page **spages; + struct iovec iov[8]; + u8 __user *buffer; + u8 *scratch; + ssize_t uncleared; + size_t bufsize, npages, size, copied; + int i; + + bufsize = 0x100000; + npages = bufsize / PAGE_SIZE; + + scratch = iov_kunit_create_buffer(test, &spages, npages); + for (i = 0; i < bufsize; i++) + scratch[i] = pattern(i); + + buffer = iov_kunit_create_user_buf(test, npages, NULL); + uncleared = clear_user(buffer, bufsize); + KUNIT_EXPECT_EQ(test, uncleared, 0); + if (uncleared) + return; + + iov_kunit_load_iovec(test, &iter, ITER_DEST, iov, ARRAY_SIZE(iov), + buffer, bufsize, kvec_test_ranges); + size = iter.count; + + copied = copy_to_iter(scratch, size, &iter); + + KUNIT_EXPECT_EQ(test, copied, size); + KUNIT_EXPECT_EQ(test, iter.count, 0); + KUNIT_EXPECT_EQ(test, iter.nr_segs, 0); + + iov_kunit_build_to_reference_pattern(test, scratch, bufsize, kvec_test_ranges); + iov_kunit_check_user_pattern(test, buffer, scratch, bufsize); + KUNIT_SUCCEED(); +} + +/* + * Test copying from an ITER_IOVEC-type iterator. + */ +static void __init iov_kunit_copy_from_iovec(struct kunit *test) +{ + struct iov_iter iter; + struct page **spages; + struct iovec iov[8]; + u8 __user *buffer; + u8 *scratch, *reference; + size_t bufsize, npages, size, copied; + + bufsize = 0x100000; + npages = bufsize / PAGE_SIZE; + + buffer = iov_kunit_create_user_buf(test, npages, NULL); + iov_kunit_fill_user_buf(test, buffer, bufsize); + + scratch = iov_kunit_create_buffer(test, &spages, npages); + memset(scratch, 0, bufsize); + + reference = iov_kunit_create_buffer(test, &spages, npages); + + iov_kunit_load_iovec(test, &iter, ITER_SOURCE, iov, ARRAY_SIZE(iov), + buffer, bufsize, kvec_test_ranges); + size = iter.count; + + copied = copy_from_iter(scratch, size, &iter); + + KUNIT_EXPECT_EQ(test, copied, size); + KUNIT_EXPECT_EQ(test, iter.count, 0); + KUNIT_EXPECT_EQ(test, iter.nr_segs, 0); + + iov_kunit_build_from_reference_pattern(test, reference, bufsize, kvec_test_ranges); + iov_kunit_check_pattern(test, reference, scratch, bufsize); + KUNIT_SUCCEED(); +} + static void __init iov_kunit_load_kvec(struct kunit *test, struct iov_iter *iter, int dir, struct kvec *kvec, unsigned int kvmax, @@ -869,6 +1101,10 @@ static void __init iov_kunit_extract_pages_xarray(struct kunit *test) }

static struct kunit_case __refdata iov_kunit_cases[] = { + KUNIT_CASE(iov_kunit_copy_to_ubuf), + KUNIT_CASE(iov_kunit_copy_from_ubuf), + KUNIT_CASE(iov_kunit_copy_to_iovec), + KUNIT_CASE(iov_kunit_copy_from_iovec), KUNIT_CASE(iov_kunit_copy_to_kvec), KUNIT_CASE(iov_kunit_copy_from_kvec), KUNIT_CASE(iov_kunit_copy_to_bvec),

David Howells

11:30 a.m.

New subject: [PATCH v3 07/10] iov_iter: Add extract kunit tests for ITER_UBUF and ITER_IOVEC

Add extraction kunit tests for ITER_UBUF- and ITER_IOVEC-type iterators. This attaches a userspace VM with a mapped file in it temporarily to the test thread.

[!] Note that this requires the kernel thread running the test to obtain and deploy an mm_struct so that a user-side buffer can be created with mmap - basically it has to emulated part of execve(). Doing so requires access to additional core symbols: mm_alloc(), vm_area_alloc(), insert_vm_struct() and arch_pick_mmap_layout(). See the iov_kunit_create_user_buf() function added in the patch.

diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c index 34f0d82674ee..fdf598e49c0b 100644 --- a/lib/kunit_iov_iter.c +++ b/lib/kunit_iov_iter.c @@ -863,6 +863,168 @@ static void __init iov_kunit_copy_from_xarray(struct kunit *test) KUNIT_SUCCEED(); }

+/* + * Test the extraction of ITER_UBUF-type iterators. + */ +static void __init iov_kunit_extract_pages_ubuf(struct kunit *test) +{ + const struct iov_kunit_range *pr; + struct iov_iter iter; + struct page **bpages, *pagelist[8], **pages = pagelist; + ssize_t len; + size_t bufsize, size = 0, npages; + int i, from; + u8 __user *buffer; + + bufsize = 0x100000; + npages = bufsize / PAGE_SIZE; + + buffer = iov_kunit_create_user_buf(test, npages, &bpages); + + for (pr = kvec_test_ranges; pr->page >= 0; pr++) { + from = pr->from; + size = pr->to - from; + KUNIT_ASSERT_LE(test, pr->to, bufsize); + + iov_iter_ubuf(&iter, ITER_SOURCE, buffer + pr->from, size); + + do { + size_t offset0 = LONG_MAX; + + for (i = 0; i < ARRAY_SIZE(pagelist); i++) + pagelist[i] = (void *)POISON_POINTER_DELTA + 0x5a; + + len = iov_iter_extract_pages(&iter, &pages, 100 * 1024, + ARRAY_SIZE(pagelist), 0, &offset0); + KUNIT_EXPECT_GE(test, len, 0); + if (len < 0) + break; + KUNIT_EXPECT_LE(test, len, size); + KUNIT_EXPECT_EQ(test, iter.count, size - len); + if (len == 0) + break; + size -= len; + KUNIT_EXPECT_GE(test, (ssize_t)offset0, 0); + KUNIT_EXPECT_LT(test, offset0, PAGE_SIZE); + + /* We're only checking the page pointers */ + unpin_user_pages(pages, (offset0 + len) / PAGE_SIZE); + + for (i = 0; i < ARRAY_SIZE(pagelist); i++) { + struct page *p; + ssize_t part = min_t(ssize_t, len, PAGE_SIZE - offset0); + int ix; + + KUNIT_ASSERT_GE(test, part, 0); + ix = from / PAGE_SIZE; + KUNIT_ASSERT_LT(test, ix, npages); + p = bpages[ix]; + KUNIT_EXPECT_PTR_EQ(test, pagelist[i], p); + KUNIT_EXPECT_EQ(test, offset0, from % PAGE_SIZE); + from += part; + len -= part; + KUNIT_ASSERT_GE(test, len, 0); + if (len == 0) + break; + offset0 = 0; + } + + if (test->status == KUNIT_FAILURE) + goto stop; + } while (iov_iter_count(&iter) > 0); + + KUNIT_EXPECT_EQ(test, size, 0); + KUNIT_EXPECT_EQ(test, iter.count, 0); + KUNIT_EXPECT_EQ(test, iter.iov_offset, pr->to - pr->from); + } + +stop: + KUNIT_SUCCEED(); +} + +/* + * Test the extraction of ITER_IOVEC-type iterators. + */ +static void __init iov_kunit_extract_pages_iovec(struct kunit *test) +{ + const struct iov_kunit_range *pr; + struct iov_iter iter; + struct iovec iov[8]; + struct page **bpages, *pagelist[8], **pages = pagelist; + ssize_t len; + size_t bufsize, size = 0, npages; + int i, from; + u8 __user *buffer; + + bufsize = 0x100000; + npages = bufsize / PAGE_SIZE; + + buffer = iov_kunit_create_user_buf(test, npages, &bpages); + + iov_kunit_load_iovec(test, &iter, ITER_SOURCE, iov, ARRAY_SIZE(iov), + buffer, bufsize, kvec_test_ranges); + size = iter.count; + + pr = kvec_test_ranges; + from = pr->from; + do { + size_t offset0 = LONG_MAX; + + for (i = 0; i < ARRAY_SIZE(pagelist); i++) + pagelist[i] = (void *)POISON_POINTER_DELTA + 0x5a; + + len = iov_iter_extract_pages(&iter, &pages, 100 * 1024, + ARRAY_SIZE(pagelist), 0, &offset0); + KUNIT_EXPECT_GE(test, len, 0); + if (len < 0) + break; + KUNIT_EXPECT_LE(test, len, size); + KUNIT_EXPECT_EQ(test, iter.count, size - len); + if (len == 0) + break; + size -= len; + KUNIT_EXPECT_GE(test, (ssize_t)offset0, 0); + KUNIT_EXPECT_LT(test, offset0, PAGE_SIZE); + + /* We're only checking the page pointers */ + unpin_user_pages(pages, (offset0 + len) / PAGE_SIZE); + + for (i = 0; i < ARRAY_SIZE(pagelist); i++) { + struct page *p; + ssize_t part = min_t(ssize_t, len, PAGE_SIZE - offset0); + int ix; + + KUNIT_ASSERT_GE(test, part, 0); + while (from == pr->to) { + pr++; + from = pr->from; + if (pr->page < 0) + goto stop; + } + + ix = from / PAGE_SIZE; + KUNIT_ASSERT_LT(test, ix, npages); + p = bpages[ix]; + KUNIT_EXPECT_PTR_EQ(test, pagelist[i], p); + KUNIT_EXPECT_EQ(test, offset0, from % PAGE_SIZE); + from += part; + len -= part; + KUNIT_ASSERT_GE(test, len, 0); + if (len == 0) + break; + offset0 = 0; + } + + if (test->status == KUNIT_FAILURE) + break; + } while (iov_iter_count(&iter) > 0); + +stop: + KUNIT_EXPECT_EQ(test, size, 0); + KUNIT_EXPECT_EQ(test, iter.count, 0); + KUNIT_SUCCEED(); +} + /* * Test the extraction of ITER_KVEC-type iterators. */ @@ -1111,6 +1273,8 @@ static struct kunit_case __refdata iov_kunit_cases[] = { KUNIT_CASE(iov_kunit_copy_from_bvec), KUNIT_CASE(iov_kunit_copy_to_xarray), KUNIT_CASE(iov_kunit_copy_from_xarray), + KUNIT_CASE(iov_kunit_extract_pages_ubuf), + KUNIT_CASE(iov_kunit_extract_pages_iovec), KUNIT_CASE(iov_kunit_extract_pages_kvec), KUNIT_CASE(iov_kunit_extract_pages_bvec), KUNIT_CASE(iov_kunit_extract_pages_xarray),

David Howells

11:30 a.m.

New subject: [PATCH v3 08/10] iov_iter: Add benchmarking kunit tests

Add kunit tests to benchmark 256MiB copies to a KVEC iterator, a BVEC iterator, an XARRAY iterator and to a loop that allocates 256-page BVECs and fills them in (similar to a maximal bio struct being set up).

Signed-off-by: David Howells dhowells@redhat.com cc: Christoph Hellwig hch@lst.de cc: Christian Brauner brauner@kernel.org cc: Jens Axboe axboe@kernel.dk cc: Al Viro viro@zeniv.linux.org.uk cc: David Hildenbrand david@redhat.com cc: John Hubbard jhubbard@nvidia.com cc: Brendan Higgins brendanhiggins@google.com cc: David Gow davidgow@google.com cc: linux-kselftest@vger.kernel.org cc: kunit-dev@googlegroups.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- lib/kunit_iov_iter.c | 251 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 251 insertions(+)

diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c index fdf598e49c0b..1a43e9518a63 100644 --- a/lib/kunit_iov_iter.c +++ b/lib/kunit_iov_iter.c @@ -1262,6 +1262,253 @@ static void __init iov_kunit_extract_pages_xarray(struct kunit *test) KUNIT_SUCCEED(); }

+static void iov_kunit_free_page(void *data) +{ + __free_page(data); +} + +#define IOV_KUNIT_NR_SAMPLES 16 +static void __init iov_kunit_benchmark_print_stats(struct kunit *test, + unsigned int *samples) +{ + unsigned long long sumsq = 0; + unsigned long total = 0, mean, stddev; + unsigned int n = IOV_KUNIT_NR_SAMPLES; + int i; + + //for (i = 0; i < n; i++) + // kunit_info(test, "run %x: %u uS\n", i, samples[i]); + + /* Ignore the 0th sample as that may include extra overhead such as + * setting up PTEs. + */ + samples++; + n--; + for (i = 0; i < n; i++) + total += samples[i]; + mean = total / n; + + for (i = 0; i < n; i++) { + long s = samples[i] - mean; + + sumsq += s * s; + } + stddev = int_sqrt64(sumsq); + + kunit_info(test, "avg %lu uS, stddev %lu uS\n", mean, stddev); +} + +/* + * Create a source buffer for benchmarking. + */ +static void *__init iov_kunit_create_source(struct kunit *test, size_t npages) +{ + struct page *page, **pages; + void *scratch; + size_t i; + + /* Allocate a page and tile it repeatedly in the buffer. */ + page = alloc_page(GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, page); + kunit_add_action_or_reset(test, iov_kunit_free_page, page); + + pages = kunit_kmalloc_array(test, npages, sizeof(pages[0]), GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, pages); + for (i = 0; i < npages; i++) { + pages[i] = page; + get_page(page); + } + + scratch = vmap(pages, npages, VM_MAP | VM_MAP_PUT_PAGES, PAGE_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, scratch); + kunit_add_action_or_reset(test, iov_kunit_unmap, scratch); + return scratch; +} + +/* + * Time copying 256MiB through an ITER_KVEC. + */ +static void __init iov_kunit_benchmark_kvec(struct kunit *test) +{ + struct iov_iter iter; + struct kvec kvec[8]; + unsigned int samples[IOV_KUNIT_NR_SAMPLES]; + ktime_t a, b; + ssize_t copied; + size_t size = 256 * 1024 * 1024, npages = size / PAGE_SIZE, part; + void *scratch, *buffer; + int i; + + /* Allocate a huge buffer and populate it with pages. */ + buffer = iov_kunit_create_source(test, npages); + + /* Create a single large buffer to copy to/from. */ + scratch = iov_kunit_create_source(test, npages); + + /* Split the target over a number of kvecs */ + copied = 0; + for (i = 0; i < ARRAY_SIZE(kvec); i++) { + part = size / ARRAY_SIZE(kvec); + kvec[i].iov_base = buffer + copied; + kvec[i].iov_len = part; + copied += part; + } + kvec[i - 1].iov_len += size - part; + + /* Perform and time a bunch of copies. */ + kunit_info(test, "Benchmarking copy_to_iter() over KVEC:\n"); + for (i = 0; i < IOV_KUNIT_NR_SAMPLES; i++) { + iov_iter_kvec(&iter, ITER_SOURCE, kvec, ARRAY_SIZE(kvec), size); + + a = ktime_get_real(); + copied = copy_from_iter(scratch, size, &iter); + b = ktime_get_real(); + KUNIT_EXPECT_EQ(test, copied, size); + samples[i] = ktime_to_us(ktime_sub(b, a)); + } + + iov_kunit_benchmark_print_stats(test, samples); + KUNIT_SUCCEED(); +} + +/* + * Time copying 256MiB through an ITER_BVEC. + */ +static void __init iov_kunit_benchmark_bvec(struct kunit *test) +{ + struct iov_iter iter; + struct bio_vec *bvec; + struct page *page; + unsigned int samples[IOV_KUNIT_NR_SAMPLES]; + ktime_t a, b; + ssize_t copied; + size_t size = 256 * 1024 * 1024, npages = size / PAGE_SIZE; + void *scratch; + int i; + + /* Allocate a page and tile it repeatedly in the buffer. */ + page = alloc_page(GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, page); + kunit_add_action_or_reset(test, iov_kunit_free_page, page); + + bvec = kunit_kmalloc_array(test, npages, sizeof(bvec[0]), GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, bvec); + for (i = 0; i < npages; i++) + bvec_set_page(&bvec[i], page, PAGE_SIZE, 0); + + /* Create a single large buffer to copy to/from. */ + scratch = iov_kunit_create_source(test, npages); + + /* Perform and time a bunch of copies. */ + kunit_info(test, "Benchmarking copy_to_iter() over BVEC:\n"); + for (i = 0; i < IOV_KUNIT_NR_SAMPLES; i++) { + iov_iter_bvec(&iter, ITER_SOURCE, bvec, npages, size); + a = ktime_get_real(); + copied = copy_from_iter(scratch, size, &iter); + b = ktime_get_real(); + KUNIT_EXPECT_EQ(test, copied, size); + samples[i] = ktime_to_us(ktime_sub(b, a)); + } + + iov_kunit_benchmark_print_stats(test, samples); + KUNIT_SUCCEED(); +} + +/* + * Time copying 256MiB through an ITER_BVEC in 256 page chunks. + */ +static void __init iov_kunit_benchmark_bvec_split(struct kunit *test) +{ + struct iov_iter iter; + struct bio_vec *bvec; + struct page *page; + unsigned int samples[IOV_KUNIT_NR_SAMPLES]; + ktime_t a, b; + ssize_t copied; + size_t size, npages = 64; + void *scratch; + int i, j; + + /* Allocate a page and tile it repeatedly in the buffer. */ + page = alloc_page(GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, page); + kunit_add_action_or_reset(test, iov_kunit_free_page, page); + + /* Create a single large buffer to copy to/from. */ + scratch = iov_kunit_create_source(test, npages); + + /* Perform and time a bunch of copies. */ + kunit_info(test, "Benchmarking copy_to_iter() over BVEC:\n"); + for (i = 0; i < IOV_KUNIT_NR_SAMPLES; i++) { + size = 256 * 1024 * 1024; + a = ktime_get_real(); + do { + size_t part = min_t(size_t, size, npages * PAGE_SIZE); + + bvec = kunit_kmalloc_array(test, npages, sizeof(bvec[0]), GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, bvec); + for (j = 0; j < npages; j++) + bvec_set_page(&bvec[j], page, PAGE_SIZE, 0); + + iov_iter_bvec(&iter, ITER_SOURCE, bvec, npages, part); + copied = copy_from_iter(scratch, part, &iter); + KUNIT_EXPECT_EQ(test, copied, part); + size -= part; + } while (size > 0); + b = ktime_get_real(); + samples[i] = ktime_to_us(ktime_sub(b, a)); + } + + iov_kunit_benchmark_print_stats(test, samples); + KUNIT_SUCCEED(); +} + +/* + * Time copying 256MiB through an ITER_XARRAY. + */ +static void __init iov_kunit_benchmark_xarray(struct kunit *test) +{ + struct iov_iter iter; + struct xarray *xarray; + struct page *page; + unsigned int samples[IOV_KUNIT_NR_SAMPLES]; + ktime_t a, b; + ssize_t copied; + size_t size = 256 * 1024 * 1024, npages = size / PAGE_SIZE; + void *scratch; + int i; + + /* Allocate a page and tile it repeatedly in the buffer. */ + page = alloc_page(GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, page); + kunit_add_action_or_reset(test, iov_kunit_free_page, page); + + xarray = iov_kunit_create_xarray(test); + + for (i = 0; i < npages; i++) { + void *x = xa_store(xarray, i, page, GFP_KERNEL); + + KUNIT_ASSERT_FALSE(test, xa_is_err(x)); + } + + /* Create a single large buffer to copy to/from. */ + scratch = iov_kunit_create_source(test, npages); + + /* Perform and time a bunch of copies. */ + kunit_info(test, "Benchmarking copy_to_iter() over XARRAY:\n"); + for (i = 0; i < IOV_KUNIT_NR_SAMPLES; i++) { + iov_iter_xarray(&iter, ITER_SOURCE, xarray, 0, size); + a = ktime_get_real(); + copied = copy_from_iter(scratch, size, &iter); + b = ktime_get_real(); + KUNIT_EXPECT_EQ(test, copied, size); + samples[i] = ktime_to_us(ktime_sub(b, a)); + } + + iov_kunit_benchmark_print_stats(test, samples); + KUNIT_SUCCEED(); +} + static struct kunit_case __refdata iov_kunit_cases[] = { KUNIT_CASE(iov_kunit_copy_to_ubuf), KUNIT_CASE(iov_kunit_copy_from_ubuf), @@ -1278,6 +1525,10 @@ static struct kunit_case __refdata iov_kunit_cases[] = { KUNIT_CASE(iov_kunit_extract_pages_kvec), KUNIT_CASE(iov_kunit_extract_pages_bvec), KUNIT_CASE(iov_kunit_extract_pages_xarray), + KUNIT_CASE(iov_kunit_benchmark_kvec), + KUNIT_CASE(iov_kunit_benchmark_bvec), + KUNIT_CASE(iov_kunit_benchmark_bvec_split), + KUNIT_CASE(iov_kunit_benchmark_xarray), {} };

David Howells

11:30 a.m.

New subject: [PATCH v3 09/10] iov_iter: Add kunit to benchmark decanting of xarray to bvec

Add a kunit test to benchmark an xarray containing 256MiB of data getting decanted into 256-page BVEC iterators that get copied from - modelling bufferage being drawn from the pagecache and batched up for I/O.

Signed-off-by: David Howells dhowells@redhat.com cc: Christoph Hellwig hch@lst.de cc: Christian Brauner brauner@kernel.org cc: Jens Axboe axboe@kernel.dk cc: Al Viro viro@zeniv.linux.org.uk cc: David Hildenbrand david@redhat.com cc: John Hubbard jhubbard@nvidia.com cc: Brendan Higgins brendanhiggins@google.com cc: David Gow davidgow@google.com cc: linux-kselftest@vger.kernel.org cc: kunit-dev@googlegroups.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- lib/kunit_iov_iter.c | 87 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+)

diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c index 1a43e9518a63..2fbe6f2afb26 100644 --- a/lib/kunit_iov_iter.c +++ b/lib/kunit_iov_iter.c @@ -1509,6 +1509,92 @@ static void __init iov_kunit_benchmark_xarray(struct kunit *test) KUNIT_SUCCEED(); }

+/* + * Time copying 256MiB through an ITER_XARRAY, decanting it to ITER_BVECs. + */ +static void __init iov_kunit_benchmark_xarray_to_bvec(struct kunit *test) +{ + struct iov_iter xiter; + struct xarray *xarray; + struct page *page; + unsigned int samples[IOV_KUNIT_NR_SAMPLES]; + ktime_t a, b; + ssize_t copied; + size_t size = 256 * 1024 * 1024, npages = size / PAGE_SIZE; + void *scratch; + int i; + + /* Allocate a page and tile it repeatedly in the buffer. */ + page = alloc_page(GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, page); + kunit_add_action_or_reset(test, iov_kunit_free_page, page); + + xarray = iov_kunit_create_xarray(test); + + for (i = 0; i < npages; i++) { + void *x = xa_store(xarray, i, page, GFP_KERNEL); + + KUNIT_ASSERT_FALSE(test, xa_is_err(x)); + } + + /* Create a single large buffer to copy to/from. */ + scratch = iov_kunit_create_source(test, npages); + + /* Perform and time a bunch of copies. */ + kunit_info(test, "Benchmarking copy_to_iter() over BVECs decanted from an XARRAY:\n"); + for (i = 0; i < IOV_KUNIT_NR_SAMPLES; i++) { + size = 256 * 1024 * 1024; + iov_iter_xarray(&xiter, ITER_SOURCE, xarray, 0, size); + a = ktime_get_real(); + + do { + struct iov_iter biter; + struct bio_vec *bvec; + struct page **pages; + size_t req, part, offset0, got; + int j; + + npages = 256; + req = min_t(size_t, size, npages * PAGE_SIZE); + bvec = kunit_kmalloc_array(test, npages, sizeof(bvec[0]), GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, bvec); + + pages = (void *)bvec + array_size(npages, sizeof(bvec[0])) - + array_size(npages, sizeof(*pages)); + + part = iov_iter_extract_pages(&xiter, &pages, req, + npages, 0, &offset0); + KUNIT_EXPECT_NE(test, part, 0); + KUNIT_EXPECT_GT(test, part, 0); + + j = 0; + got = part; + do { + size_t chunk = min_t(size_t, got, PAGE_SIZE - offset0); + + bvec_set_page(&bvec[j++], page, chunk, offset0); + offset0 = 0; + got -= chunk; + } while (got > 0); + + iov_iter_bvec(&biter, ITER_SOURCE, bvec, j, part); + copied = copy_from_iter(scratch, part, &biter); + KUNIT_EXPECT_EQ(test, copied, part); + size -= copied; + if (test->status == KUNIT_FAILURE) + break; + } while (size > 0); + + b = ktime_get_real(); + samples[i] = ktime_to_us(ktime_sub(b, a)); + if (test->status == KUNIT_FAILURE) + break; + } + + iov_kunit_benchmark_print_stats(test, samples); + KUNIT_SUCCEED(); +} + static struct kunit_case __refdata iov_kunit_cases[] = { KUNIT_CASE(iov_kunit_copy_to_ubuf), KUNIT_CASE(iov_kunit_copy_from_ubuf), @@ -1529,6 +1615,7 @@ static struct kunit_case __refdata iov_kunit_cases[] = { KUNIT_CASE(iov_kunit_benchmark_bvec), KUNIT_CASE(iov_kunit_benchmark_bvec_split), KUNIT_CASE(iov_kunit_benchmark_xarray), + KUNIT_CASE(iov_kunit_benchmark_xarray_to_bvec), {} };

David Howells

11:30 a.m.

New subject: [PATCH v3 10/10] iov_iter: Add benchmarking kunit tests for UBUF/IOVEC

Add kunit tests to benchmark 256MiB copies to a UBUF iterator and an IOVEC iterator. This attaches a userspace VM with a mapped file in it temporarily to the test thread.

diff --git a/lib/kunit_iov_iter.c b/lib/kunit_iov_iter.c index 2fbe6f2afb26..d5b7517f4f47 100644 --- a/lib/kunit_iov_iter.c +++ b/lib/kunit_iov_iter.c @@ -1325,6 +1325,99 @@ static void *__init iov_kunit_create_source(struct kunit *test, size_t npages) return scratch; }

+/* + * Time copying 256MiB through an ITER_UBUF. + */ +static void __init iov_kunit_benchmark_ubuf(struct kunit *test) +{ + struct iov_iter iter; + unsigned int samples[IOV_KUNIT_NR_SAMPLES]; + ktime_t a, b; + ssize_t copied; + size_t size = 256 * 1024 * 1024, npages = size / PAGE_SIZE; + void *scratch; + int i; + u8 __user *buffer; + + /* Allocate a huge buffer and populate it with pages. */ + buffer = iov_kunit_create_user_buf(test, npages, NULL); + + /* Create a single large buffer to copy to/from. */ + scratch = iov_kunit_create_source(test, npages); + + /* Perform and time a bunch of copies. */ + kunit_info(test, "Benchmarking copy_to_iter() over UBUF:\n"); + for (i = 0; i < IOV_KUNIT_NR_SAMPLES; i++) { + size_t remain = size; + + a = ktime_get_real(); + do { + size_t part = min(remain, PAGE_SIZE); + + iov_iter_ubuf(&iter, ITER_SOURCE, buffer, part); + copied = copy_from_iter(scratch, part, &iter); + KUNIT_EXPECT_EQ(test, copied, part); + remain -= part; + } while (remain > 0); + b = ktime_get_real(); + samples[i] = ktime_to_us(ktime_sub(b, a)); + } + + iov_kunit_benchmark_print_stats(test, samples); + KUNIT_SUCCEED(); +} + +/* + * Time copying 256MiB through an ITER_IOVEC. + */ +static void __init iov_kunit_benchmark_iovec(struct kunit *test) +{ + struct iov_iter iter; + struct iovec *iov; + unsigned int samples[IOV_KUNIT_NR_SAMPLES]; + ktime_t a, b; + ssize_t copied; + size_t size = 256 * 1024 * 1024, npages = size / PAGE_SIZE, part; + size_t ioc = size / PAGE_SIZE; + void *scratch; + int i; + u8 __user *buffer; + + iov = kunit_kmalloc_array(test, ioc, sizeof(*iov), GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, iov); + + /* Allocate a huge buffer and populate it with pages. */ + buffer = iov_kunit_create_user_buf(test, npages, NULL); + + /* Create a single large buffer to copy to/from. */ + scratch = iov_kunit_create_source(test, npages); + + /* Split the target over a number of iovecs */ + copied = 0; + for (i = 0; i < ioc; i++) { + part = size / ioc; + iov[i].iov_base = buffer + copied; + iov[i].iov_len = part; + copied += part; + } + iov[i - 1].iov_len += size - part; + + /* Perform and time a bunch of copies. */ + kunit_info(test, "Benchmarking copy_to_iter() over IOVEC:\n"); + for (i = 0; i < IOV_KUNIT_NR_SAMPLES; i++) { + iov_iter_init(&iter, ITER_SOURCE, iov, npages, size); + + a = ktime_get_real(); + copied = copy_from_iter(scratch, size, &iter); + b = ktime_get_real(); + KUNIT_EXPECT_EQ(test, copied, size); + samples[i] = ktime_to_us(ktime_sub(b, a)); + } + + iov_kunit_benchmark_print_stats(test, samples); + KUNIT_SUCCEED(); +} + /* * Time copying 256MiB through an ITER_KVEC. */ @@ -1611,6 +1704,8 @@ static struct kunit_case __refdata iov_kunit_cases[] = { KUNIT_CASE(iov_kunit_extract_pages_kvec), KUNIT_CASE(iov_kunit_extract_pages_bvec), KUNIT_CASE(iov_kunit_extract_pages_xarray), + KUNIT_CASE(iov_kunit_benchmark_ubuf), + KUNIT_CASE(iov_kunit_benchmark_iovec), KUNIT_CASE(iov_kunit_benchmark_kvec), KUNIT_CASE(iov_kunit_benchmark_bvec), KUNIT_CASE(iov_kunit_benchmark_bvec_split),

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David Howells