- Linux-kselftest-mirror - lists.linaro.org

[PATCH v2] kunit: fix checkpatch warning

by Lucas Stankus

Tidy up code by fixing the following checkpatch warnings: CHECK: Alignment should match open parenthesis CHECK: Lines should not end with a '(' Signed-off-by: Lucas Stankus <lucas.p.stankus(a)gmail.com> --- Change log v1 -> v2 fixed signed-off-by tag lib/kunit/assert.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) diff --git a/lib/kunit/assert.c b/lib/kunit/assert.c index e0ec7d6fed6f..acfbf86bddd6 100644 --- a/lib/kunit/assert.c +++ b/lib/kunit/assert.c @@ -25,7 +25,7 @@ void kunit_base_assert_format(const struct kunit_assert *assert, } string_stream_add(stream, "%s FAILED at %s:%d\n", - expect_or_assert, assert->file, assert->line); + expect_or_assert, assert->file, assert->line); } EXPORT_SYMBOL_GPL(kunit_base_assert_format); @@ -48,8 +48,9 @@ EXPORT_SYMBOL_GPL(kunit_fail_assert_format); void kunit_unary_assert_format(const struct kunit_assert *assert, struct string_stream *stream) { - struct kunit_unary_assert *unary_assert = container_of( - assert, struct kunit_unary_assert, assert); + struct kunit_unary_assert *unary_assert; + + unary_assert = container_of(assert, struct kunit_unary_assert, assert); kunit_base_assert_format(assert, stream); if (unary_assert->expected_true) @@ -67,8 +68,10 @@ EXPORT_SYMBOL_GPL(kunit_unary_assert_format); void kunit_ptr_not_err_assert_format(const struct kunit_assert *assert, struct string_stream *stream) { - struct kunit_ptr_not_err_assert *ptr_assert = container_of( - assert, struct kunit_ptr_not_err_assert, assert); + struct kunit_ptr_not_err_assert *ptr_assert; + + ptr_assert = container_of(assert, struct kunit_ptr_not_err_assert, + assert); kunit_base_assert_format(assert, stream); if (!ptr_assert->value) { @@ -111,8 +114,10 @@ static bool is_literal(struct kunit *test, const char *text, long long value, void kunit_binary_assert_format(const struct kunit_assert *assert, struct string_stream *stream) { - struct kunit_binary_assert *binary_assert = container_of( - assert, struct kunit_binary_assert, assert); + struct kunit_binary_assert *binary_assert; + + binary_assert = container_of(assert, struct kunit_binary_assert, + assert); kunit_base_assert_format(assert, stream); string_stream_add(stream, @@ -137,8 +142,10 @@ EXPORT_SYMBOL_GPL(kunit_binary_assert_format); void kunit_binary_ptr_assert_format(const struct kunit_assert *assert, struct string_stream *stream) { - struct kunit_binary_ptr_assert *binary_assert = container_of( - assert, struct kunit_binary_ptr_assert, assert); + struct kunit_binary_ptr_assert *binary_assert; + + binary_assert = container_of(assert, struct kunit_binary_ptr_assert, + assert); kunit_base_assert_format(assert, stream); string_stream_add(stream, @@ -159,8 +166,10 @@ EXPORT_SYMBOL_GPL(kunit_binary_ptr_assert_format); void kunit_binary_str_assert_format(const struct kunit_assert *assert, struct string_stream *stream) { - struct kunit_binary_str_assert *binary_assert = container_of( - assert, struct kunit_binary_str_assert, assert); + struct kunit_binary_str_assert *binary_assert; + + binary_assert = container_of(assert, struct kunit_binary_str_assert, + assert); kunit_base_assert_format(assert, stream); string_stream_add(stream, -- 2.30.1

4 years, 3 months

3
4
0 0

[PATCH] kselftest: arm64: Fix exit code of sve-ptrace

by Mark Brown

We track if sve-ptrace encountered a failure in a variable but don't actually use that value when we exit the program, do so. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- tools/testing/selftests/arm64/fp/sve-ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/arm64/fp/sve-ptrace.c b/tools/testing/selftests/arm64/fp/sve-ptrace.c index b2282be6f938..612d3899614a 100644 --- a/tools/testing/selftests/arm64/fp/sve-ptrace.c +++ b/tools/testing/selftests/arm64/fp/sve-ptrace.c @@ -332,5 +332,5 @@ int main(void) ksft_print_cnts(); - return 0; + return ret; } -- 2.20.1

4 years, 3 months

2
1
0 0

[PATCH v2 0/5] userfaultfd: support minor fault handling for shmem

by Axel Rasmussen

Base ==== This series is based on top of my series which adds minor fault handling for hugetlbfs [1]. (And, therefore, it is based on 5.12-rc1 and Peter Xu's series for disabling huge pmd sharing as well.) [1] https://lore.kernel.org/linux-fsdevel/20210301222728.176417-1-axelrasmussen… Changelog ========= v1->v2: - For UFFDIO_CONTINUE, don't mess with page flags. Just use find_lock_page to get a locked page from the page cache, instead of doing __SetPageLocked. This fixes a VM_BUG_ON v1 hit when handling minor faults for THP-backed shmem (a tmpfs mounted with huge=always). Overview ======== See my original series linked above for a detailed overview of minor fault handling in general. The feature in this series works exactly like the hugetblfs version (from userspace's perspective). I'm sending this as a separate series because: - The original minor fault handling series has a full set of R-Bs, and seems close to being merged. So, it seems reasonable to start looking at this next step, which extends the basic functionality. - shmem is different enough that this series may require some additional work before it's ready, and I don't want to delay the original series unnecessarily by bundling them together. Use Case ======== In some cases it is useful to have VM memory backed by tmpfs instead of hugetlbfs. So, this feature will be used to support the same VM live migration use case described in my original series. Additionally, Android folks (Lokesh Gidra <lokeshgidra(a)google.com>) hope to optimize the Android Runtime garbage collector using this feature: "The plan is to use userfaultfd for concurrently compacting the heap. With this feature, the heap can be shared-mapped at another location where the GC-thread(s) could continue the compaction operation without the need to invoke userfault ioctl(UFFDIO_COPY) each time. OTOH, if and when Java threads get faults on the heap, UFFDIO_CONTINUE can be used to resume execution. Furthermore, this feature enables updating references in the 'non-moving' portion of the heap efficiently. Without this feature, uneccessary page copying (ioctl(UFFDIO_COPY)) would be required." Axel Rasmussen (5): userfaultfd: support minor fault handling for shmem userfaultfd/selftests: use memfd_create for shmem test type userfaultfd/selftests: create alias mappings in the shmem test userfaultfd/selftests: reinitialize test context in each test userfaultfd/selftests: exercise minor fault handling shmem support fs/userfaultfd.c | 6 +- include/linux/shmem_fs.h | 26 +- include/uapi/linux/userfaultfd.h | 4 +- mm/memory.c | 8 +- mm/shmem.c | 92 +++---- mm/userfaultfd.c | 27 +- tools/testing/selftests/vm/userfaultfd.c | 322 +++++++++++++++-------- 7 files changed, 295 insertions(+), 190 deletions(-) -- 2.30.1.766.gb4fecdf3b7-goog

4 years, 3 months

2
9
0 0

[PATCH] mm: huge_memory: a new debugfs interface for splitting THP tests.

by Zi Yan

From: Zi Yan <ziy(a)nvidia.com> By writing "<pid>,<vaddr_start>,<vaddr_end>" to <debugfs>/split_huge_pages_in_range_pid, THPs in the process with the given pid and virtual address range are split. It is used to test split_huge_page function. In addition, a selftest program is added to tools/testing/selftests/vm to utilize the interface by splitting PMD THPs and PTE-mapped THPs. Signed-off-by: Zi Yan <ziy(a)nvidia.com> --- mm/huge_memory.c | 98 ++++++ mm/internal.h | 1 + mm/migrate.c | 2 +- tools/testing/selftests/vm/.gitignore | 1 + tools/testing/selftests/vm/Makefile | 1 + .../selftests/vm/split_huge_page_test.c | 318 ++++++++++++++++++ 6 files changed, 420 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/vm/split_huge_page_test.c diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 395c75111d33..818172f887bf 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -7,6 +7,7 @@ #include <linux/mm.h> #include <linux/sched.h> +#include <linux/sched/mm.h> #include <linux/sched/coredump.h> #include <linux/sched/numa_balancing.h> #include <linux/highmem.h> @@ -2971,10 +2972,107 @@ static int split_huge_pages_set(void *data, u64 val) DEFINE_DEBUGFS_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, "%llu\n"); +static ssize_t split_huge_pages_in_range_pid_write(struct file *file, + const char __user *buf, size_t count, loff_t *ppops) +{ + static DEFINE_MUTEX(mutex); + ssize_t ret; + char input_buf[80]; /* hold pid, start_vaddr, end_vaddr */ + int pid; + unsigned long vaddr_start, vaddr_end, addr; + nodemask_t task_nodes; + struct mm_struct *mm; + unsigned long total = 0, split = 0; + + ret = mutex_lock_interruptible(&mutex); + if (ret) + return ret; + + ret = -EFAULT; + + memset(input_buf, 0, 80); + if (copy_from_user(input_buf, buf, min_t(size_t, count, 80))) + goto out; + + input_buf[79] = '\0'; + ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); + if (ret != 3) { + ret = -EINVAL; + goto out; + } + vaddr_start &= PAGE_MASK; + vaddr_end &= PAGE_MASK; + + ret = strlen(input_buf); + pr_debug("split huge pages in pid: %d, vaddr: [%lx - %lx]\n", + pid, vaddr_start, vaddr_end); + + mm = find_mm_struct(pid, &task_nodes); + if (IS_ERR(mm)) { + ret = -EINVAL; + goto out; + } + + mmap_read_lock(mm); + /* + * always increase addr by PAGE_SIZE, since we could have a PTE page + * table filled with PTE-mapped THPs, each of which is distinct. + */ + for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { + struct vm_area_struct *vma = find_vma(mm, addr); + unsigned int follflags; + struct page *page; + + if (!vma || addr < vma->vm_start || !vma_migratable(vma)) + break; + + /* FOLL_DUMP to ignore special (like zero) pages */ + follflags = FOLL_GET | FOLL_DUMP; + page = follow_page(vma, addr, follflags); + + if (IS_ERR(page)) + break; + if (!page) + break; + + if (!is_transparent_hugepage(page)) + continue; + + total++; + if (!can_split_huge_page(compound_head(page), NULL)) + continue; + + if (!trylock_page(page)) + continue; + + if (!split_huge_page(page)) + split++; + + unlock_page(page); + put_page(page); + } + mmap_read_unlock(mm); + mmput(mm); + + pr_debug("%lu of %lu THP split\n", split, total); +out: + mutex_unlock(&mutex); + return ret; + +} + +static const struct file_operations split_huge_pages_in_range_pid_fops = { + .owner = THIS_MODULE, + .write = split_huge_pages_in_range_pid_write, + .llseek = no_llseek, +}; + static int __init split_huge_pages_debugfs(void) { debugfs_create_file("split_huge_pages", 0200, NULL, NULL, &split_huge_pages_fops); + debugfs_create_file("split_huge_pages_in_range_pid", 0200, NULL, NULL, + &split_huge_pages_in_range_pid_fops); return 0; } late_initcall(split_huge_pages_debugfs); diff --git a/mm/internal.h b/mm/internal.h index 9902648f2206..1659d00100ef 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -623,4 +623,5 @@ struct migration_target_control { gfp_t gfp_mask; }; +struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes); #endif /* __MM_INTERNAL_H */ diff --git a/mm/migrate.c b/mm/migrate.c index 62b81d5257aa..ce5f213debb2 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1913,7 +1913,7 @@ static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages, return nr_pages ? -EFAULT : 0; } -static struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes) +struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes) { struct task_struct *task; struct mm_struct *mm; diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore index 9a35c3f6a557..1f651e85ed60 100644 --- a/tools/testing/selftests/vm/.gitignore +++ b/tools/testing/selftests/vm/.gitignore @@ -22,3 +22,4 @@ map_fixed_noreplace write_to_hugetlbfs hmm-tests local_config.* +split_huge_page_test diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile index d42115e4284d..4cbc91d6869f 100644 --- a/tools/testing/selftests/vm/Makefile +++ b/tools/testing/selftests/vm/Makefile @@ -42,6 +42,7 @@ TEST_GEN_FILES += on-fault-limit TEST_GEN_FILES += thuge-gen TEST_GEN_FILES += transhuge-stress TEST_GEN_FILES += userfaultfd +TEST_GEN_FILES += split_huge_page_test ifeq ($(MACHINE),x86_64) CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh $(CC) ../x86/trivial_32bit_program.c -m32) diff --git a/tools/testing/selftests/vm/split_huge_page_test.c b/tools/testing/selftests/vm/split_huge_page_test.c new file mode 100644 index 000000000000..8ea8000fda62 --- /dev/null +++ b/tools/testing/selftests/vm/split_huge_page_test.c @@ -0,0 +1,318 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * A test of splitting PMD THPs and PTE-mapped THPs from a specified virtual + * address range in a process via <debugfs>/split_huge_pages_in_range_pid + * interface. + */ + +#define _GNU_SOURCE +#include <stdio.h> +#include <stdlib.h> +#include "numa.h" +#include <unistd.h> +#include <errno.h> +#include <inttypes.h> +#include <string.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <sys/mman.h> +#include <sys/time.h> +#include <sys/wait.h> +#include <malloc.h> +#include <stdbool.h> + +uint64_t pagesize; +unsigned int pageshift; +uint64_t pmd_pagesize; + +#define PMD_SIZE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size" +#define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages_in_range_pid" +#define SMAP_PATH "/proc/self/smaps" +#define INPUT_MAX 80 + +#define PFN_MASK ((1UL<<55)-1) +#define KPF_THP (1UL<<22) + +int is_backed_by_thp(char *vaddr, int pagemap_file, int kpageflags_file) +{ + uint64_t paddr; + uint64_t page_flags; + + if (pagemap_file) { + pread(pagemap_file, &paddr, sizeof(paddr), + ((long)vaddr >> pageshift) * sizeof(paddr)); + + if (kpageflags_file) { + pread(kpageflags_file, &page_flags, sizeof(page_flags), + (paddr & PFN_MASK) * sizeof(page_flags)); + + return !!(page_flags & KPF_THP); + } + } + return 0; +} + + +static uint64_t read_pmd_pagesize(void) +{ + int fd; + char buf[20]; + ssize_t num_read; + + fd = open(PMD_SIZE_PATH, O_RDONLY); + if (fd == -1) { + perror("Open hpage_pmd_size failed"); + exit(EXIT_FAILURE); + } + num_read = read(fd, buf, 19); + if (num_read < 1) { + close(fd); + perror("Read hpage_pmd_size failed"); + exit(EXIT_FAILURE); + } + buf[num_read] = '\0'; + close(fd); + + return strtoul(buf, NULL, 10); +} + +static int write_file(const char *path, const char *buf, size_t buflen) +{ + int fd; + ssize_t numwritten; + + fd = open(path, O_WRONLY); + if (fd == -1) + return 0; + + numwritten = write(fd, buf, buflen - 1); + close(fd); + if (numwritten < 1) + return 0; + + return (unsigned int) numwritten; +} + +static void write_debugfs(int pid, uint64_t vaddr_start, uint64_t vaddr_end) +{ + char input[INPUT_MAX]; + int ret; + + ret = snprintf(input, INPUT_MAX, "%d,0x%lx,0x%lx", pid, vaddr_start, + vaddr_end); + if (ret >= INPUT_MAX) { + printf("%s: Debugfs input is too long\n", __func__); + exit(EXIT_FAILURE); + } + + if (!write_file(SPLIT_DEBUGFS, input, ret + 1)) { + perror(SPLIT_DEBUGFS); + exit(EXIT_FAILURE); + } +} + +#define MAX_LINE_LENGTH 500 + +static bool check_for_pattern(FILE *fp, const char *pattern, char *buf) +{ + while (fgets(buf, MAX_LINE_LENGTH, fp) != NULL) { + if (!strncmp(buf, pattern, strlen(pattern))) + return true; + } + return false; +} + +static uint64_t check_huge(void *addr) +{ + uint64_t thp = 0; + int ret; + FILE *fp; + char buffer[MAX_LINE_LENGTH]; + char addr_pattern[MAX_LINE_LENGTH]; + + ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-", + (unsigned long) addr); + if (ret >= MAX_LINE_LENGTH) { + printf("%s: Pattern is too long\n", __func__); + exit(EXIT_FAILURE); + } + + + fp = fopen(SMAP_PATH, "r"); + if (!fp) { + printf("%s: Failed to open file %s\n", __func__, SMAP_PATH); + exit(EXIT_FAILURE); + } + if (!check_for_pattern(fp, addr_pattern, buffer)) + goto err_out; + + /* + * Fetch the AnonHugePages: in the same block and check the number of + * hugepages. + */ + if (!check_for_pattern(fp, "AnonHugePages:", buffer)) + goto err_out; + + if (sscanf(buffer, "AnonHugePages:%10ld kB", &thp) != 1) { + printf("Reading smap error\n"); + exit(EXIT_FAILURE); + } + +err_out: + fclose(fp); + return thp; +} + +void split_pmd_thp(void) +{ + char *one_page; + size_t len = 4 * pmd_pagesize; + uint64_t thp_size; + size_t i; + + one_page = memalign(pmd_pagesize, len); + + madvise(one_page, len, MADV_HUGEPAGE); + + for (i = 0; i < len; i++) + one_page[i] = (char)i; + + thp_size = check_huge(one_page); + if (!thp_size) { + printf("No THP is allocatd"); + exit(EXIT_FAILURE); + } + + /* split all possible huge pages */ + write_debugfs(getpid(), (uint64_t)one_page, (uint64_t)one_page + len); + + for (i = 0; i < len; i++) + if (one_page[i] != (char)i) { + printf("%ld byte corrupted\n", i); + exit(EXIT_FAILURE); + } + + + thp_size = check_huge(one_page); + if (thp_size) { + printf("Still %ld kB AnonHugePages not split\n", thp_size); + exit(EXIT_FAILURE); + } + + printf("Split huge pages successful\n"); + free(one_page); +} + +void split_pte_mapped_thp(void) +{ + char *one_page, *pte_mapped, *pte_mapped2; + size_t len = 4 * pmd_pagesize; + uint64_t thp_size; + size_t i; + const char *pagemap_template = "/proc/%d/pagemap"; + const char *kpageflags_proc = "/proc/kpageflags"; + char pagemap_proc[255]; + int pagemap_fd; + int kpageflags_fd; + + if (snprintf(pagemap_proc, 255, pagemap_template, getpid()) < 0) { + perror("get pagemap proc error"); + exit(EXIT_FAILURE); + } + pagemap_fd = open(pagemap_proc, O_RDONLY); + + if (pagemap_fd == -1) { + perror("read pagemap:"); + exit(EXIT_FAILURE); + } + + kpageflags_fd = open(kpageflags_proc, O_RDONLY); + + if (kpageflags_fd == -1) { + perror("read kpageflags:"); + exit(EXIT_FAILURE); + } + + one_page = mmap((void *)(1UL << 30), len, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + + madvise(one_page, len, MADV_HUGEPAGE); + + for (i = 0; i < len; i++) + one_page[i] = (char)i; + + thp_size = check_huge(one_page); + if (!thp_size) { + printf("No THP is allocatd"); + exit(EXIT_FAILURE); + } + + pte_mapped = mremap(one_page, pagesize, pagesize, MREMAP_MAYMOVE); + + for (i = 1; i < 4; i++) { + pte_mapped2 = mremap(one_page + pmd_pagesize * i + pagesize * i, + pagesize, pagesize, + MREMAP_MAYMOVE|MREMAP_FIXED, + pte_mapped + pagesize * i); + if (pte_mapped2 == (char *)-1) { + perror("mremap failed"); + exit(EXIT_FAILURE); + } + } + + /* smap does not show THPs after mremap, use kpageflags instead */ + thp_size = 0; + for (i = 0; i < pagesize * 4; i++) + if (i % pagesize == 0 && + is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd)) + thp_size++; + + if (thp_size != 4) { + printf("Some THPs are missing during mremap\n"); + exit(EXIT_FAILURE); + } + + /* split all possible huge pages */ + write_debugfs(getpid(), (uint64_t)pte_mapped, + (uint64_t)pte_mapped + pagesize * 4); + + /* smap does not show THPs after mremap, use kpageflags instead */ + thp_size = 0; + for (i = 0; i < pagesize * 4; i++) { + if (pte_mapped[i] != (char)i) { + printf("%ld byte corrupted\n", i); + exit(EXIT_FAILURE); + } + if (i % pagesize == 0 && + is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd)) + thp_size++; + } + + if (thp_size) { + printf("Still %ld THPs not split\n", thp_size); + exit(EXIT_FAILURE); + } + + printf("Split PTE-mapped huge pages successful\n"); + munmap(one_page, len); + close(pagemap_fd); + close(kpageflags_fd); +} + +int main(int argc, char **argv) +{ + if (geteuid() != 0) { + printf("Please run the benchmark as root\n"); + exit(EXIT_FAILURE); + } + + pagesize = getpagesize(); + pageshift = ffs(pagesize) - 1; + pmd_pagesize = read_pmd_pagesize(); + + split_pmd_thp(); + split_pte_mapped_thp(); + + return 0; +} -- 2.30.1

4 years, 3 months

5
13
0 0

[PATCH bpf-next] selftests/bpf: Fix typo in Makefile

by Jean-Philippe Brucker

The selftest build fails when trying to install the scripts: rsync: [sender] link_stat "tools/testing/selftests/bpf/test_docs_build.sh" failed: No such file or directory (2) Fix the filename. Fixes: a01d935b2e09 ("tools/bpf: Remove bpf-helpers from bpftool docs") Signed-off-by: Jean-Philippe Brucker <jean-philippe(a)linaro.org> --- tools/testing/selftests/bpf/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index b5827464c6b5..c3999587bc23 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -68,7 +68,7 @@ TEST_PROGS := test_kmod.sh \ test_bpftool_build.sh \ test_bpftool.sh \ test_bpftool_metadata.sh \ - test_docs_build.sh \ + test_doc_build.sh \ test_xsk.sh TEST_PROGS_EXTENDED := with_addr.sh \ -- 2.30.1

4 years, 3 months

3
2
0 0

Re: [PATCH] mm: huge_memory: a new debugfs interface for splitting THP tests.

by Zi Yan

+ the rest of cc back and move your reply inline. On 8 Mar 2021, at 12:47, Mika Penttilä wrote: >> >> >> On 8.3.2021 17.22, Zi Yan wrote: >>> From: Zi Yan <ziy(a)nvidia.com> >>> >>> By writing "<pid>,<vaddr_start>,<vaddr_end>" to >>> <debugfs>/split_huge_pages_in_range_pid, THPs in the process with the >>> given pid and virtual address range are split. It is used to test >>> split_huge_page function. In addition, a selftest program is added to >>> tools/testing/selftests/vm to utilize the interface by splitting >>> PMD THPs and PTE-mapped THPs. >>> >>> Signed-off-by: Zi Yan <ziy(a)nvidia.com> >> >> Hi! >> >> I think your test program is not correct. The mremaps shrink to one page, after the first mremap the pointers are bogus. >> Also, mremap splits pmds with split_huge_pmd().. And those you can't split with split_huge_page because it is a normal pmd. >> Maybe you didn't indent to shrink to page size? >> >> >> --Mika > Hi, > > Sorry, wrote too fast.. the splits are okay of course from pte mapped thp to plain pages (mremap -> split pmd -> debugfs write ->split pages). > But the remap offsets are I think maybe not you wanted. You mean I mremap the first PAGESIZE from first THP, second PAGESIZE from second THP and so on to create PTE-mapped THPs? I did it on purpose so split_huge_page can work on different part of THPs. >> >> >>> --- >>> mm/huge_memory.c | 98 ++++++ >>> mm/internal.h | 1 + >>> mm/migrate.c | 2 +- >>> tools/testing/selftests/vm/.gitignore | 1 + >>> tools/testing/selftests/vm/Makefile | 1 + >>> .../selftests/vm/split_huge_page_test.c | 318 ++++++++++++++++++ >>> 6 files changed, 420 insertions(+), 1 deletion(-) >>> create mode 100644 tools/testing/selftests/vm/split_huge_page_test.c >>> >>> diff --git a/mm/huge_memory.c b/mm/huge_memory.c >>> index 395c75111d33..818172f887bf 100644 >>> --- a/mm/huge_memory.c >>> +++ b/mm/huge_memory.c >>> @@ -7,6 +7,7 @@ >>> #include <linux/mm.h> >>> #include <linux/sched.h> >>> +#include <linux/sched/mm.h> >>> #include <linux/sched/coredump.h> >>> #include <linux/sched/numa_balancing.h> >>> #include <linux/highmem.h> >>> @@ -2971,10 +2972,107 @@ static int split_huge_pages_set(void *data, u64 val) >>> DEFINE_DEBUGFS_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, >>> "%llu\n"); >>> +static ssize_t split_huge_pages_in_range_pid_write(struct file *file, >>> + const char __user *buf, size_t count, loff_t *ppops) >>> +{ >>> + static DEFINE_MUTEX(mutex); >>> + ssize_t ret; >>> + char input_buf[80]; /* hold pid, start_vaddr, end_vaddr */ >>> + int pid; >>> + unsigned long vaddr_start, vaddr_end, addr; >>> + nodemask_t task_nodes; >>> + struct mm_struct *mm; >>> + unsigned long total = 0, split = 0; >>> + >>> + ret = mutex_lock_interruptible(&mutex); >>> + if (ret) >>> + return ret; >>> + >>> + ret = -EFAULT; >>> + >>> + memset(input_buf, 0, 80); >>> + if (copy_from_user(input_buf, buf, min_t(size_t, count, 80))) >>> + goto out; >>> + >>> + input_buf[79] = '\0'; >>> + ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); >>> + if (ret != 3) { >>> + ret = -EINVAL; >>> + goto out; >>> + } >>> + vaddr_start &= PAGE_MASK; >>> + vaddr_end &= PAGE_MASK; >>> + >>> + ret = strlen(input_buf); >>> + pr_debug("split huge pages in pid: %d, vaddr: [%lx - %lx]\n", >>> + pid, vaddr_start, vaddr_end); >>> + >>> + mm = find_mm_struct(pid, &task_nodes); >>> + if (IS_ERR(mm)) { >>> + ret = -EINVAL; >>> + goto out; >>> + } >>> + >>> + mmap_read_lock(mm); >>> + /* >>> + * always increase addr by PAGE_SIZE, since we could have a PTE page >>> + * table filled with PTE-mapped THPs, each of which is distinct. >>> + */ >>> + for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { >>> + struct vm_area_struct *vma = find_vma(mm, addr); >>> + unsigned int follflags; >>> + struct page *page; >>> + >>> + if (!vma || addr < vma->vm_start || !vma_migratable(vma)) >>> + break; >>> + >>> + /* FOLL_DUMP to ignore special (like zero) pages */ >>> + follflags = FOLL_GET | FOLL_DUMP; >>> + page = follow_page(vma, addr, follflags); >>> + >>> + if (IS_ERR(page)) >>> + break; >>> + if (!page) >>> + break; >>> + >>> + if (!is_transparent_hugepage(page)) >>> + continue; >>> + >>> + total++; >>> + if (!can_split_huge_page(compound_head(page), NULL)) >>> + continue; >>> + >>> + if (!trylock_page(page)) >>> + continue; >>> + >>> + if (!split_huge_page(page)) >>> + split++; >>> + >>> + unlock_page(page); >>> + put_page(page); >>> + } >>> + mmap_read_unlock(mm); >>> + mmput(mm); >>> + >>> + pr_debug("%lu of %lu THP split\n", split, total); >>> +out: >>> + mutex_unlock(&mutex); >>> + return ret; >>> + >>> +} >>> + >>> +static const struct file_operations split_huge_pages_in_range_pid_fops = { >>> + .owner = THIS_MODULE, >>> + .write = split_huge_pages_in_range_pid_write, >>> + .llseek = no_llseek, >>> +}; >>> + >>> static int __init split_huge_pages_debugfs(void) >>> { >>> debugfs_create_file("split_huge_pages", 0200, NULL, NULL, >>> &split_huge_pages_fops); >>> + debugfs_create_file("split_huge_pages_in_range_pid", 0200, NULL, NULL, >>> + &split_huge_pages_in_range_pid_fops); >>> return 0; >>> } >>> late_initcall(split_huge_pages_debugfs); >>> diff --git a/mm/internal.h b/mm/internal.h >>> index 9902648f2206..1659d00100ef 100644 >>> --- a/mm/internal.h >>> +++ b/mm/internal.h >>> @@ -623,4 +623,5 @@ struct migration_target_control { >>> gfp_t gfp_mask; >>> }; >>> +struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes); >>> #endif /* __MM_INTERNAL_H */ >>> diff --git a/mm/migrate.c b/mm/migrate.c >>> index 62b81d5257aa..ce5f213debb2 100644 >>> --- a/mm/migrate.c >>> +++ b/mm/migrate.c >>> @@ -1913,7 +1913,7 @@ static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages, >>> return nr_pages ? -EFAULT : 0; >>> } >>> -static struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes) >>> +struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes) >>> { >>> struct task_struct *task; >>> struct mm_struct *mm; >>> diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore >>> index 9a35c3f6a557..1f651e85ed60 100644 >>> --- a/tools/testing/selftests/vm/.gitignore >>> +++ b/tools/testing/selftests/vm/.gitignore >>> @@ -22,3 +22,4 @@ map_fixed_noreplace >>> write_to_hugetlbfs >>> hmm-tests >>> local_config.* >>> +split_huge_page_test >>> diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile >>> index d42115e4284d..4cbc91d6869f 100644 >>> --- a/tools/testing/selftests/vm/Makefile >>> +++ b/tools/testing/selftests/vm/Makefile >>> @@ -42,6 +42,7 @@ TEST_GEN_FILES += on-fault-limit >>> TEST_GEN_FILES += thuge-gen >>> TEST_GEN_FILES += transhuge-stress >>> TEST_GEN_FILES += userfaultfd >>> +TEST_GEN_FILES += split_huge_page_test >>> ifeq ($(MACHINE),x86_64) >>> CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh $(CC) ../x86/trivial_32bit_program.c -m32) >>> diff --git a/tools/testing/selftests/vm/split_huge_page_test.c b/tools/testing/selftests/vm/split_huge_page_test.c >>> new file mode 100644 >>> index 000000000000..8ea8000fda62 >>> --- /dev/null >>> +++ b/tools/testing/selftests/vm/split_huge_page_test.c >>> @@ -0,0 +1,318 @@ >>> +// SPDX-License-Identifier: GPL-2.0 >>> +/* >>> + * A test of splitting PMD THPs and PTE-mapped THPs from a specified virtual >>> + * address range in a process via <debugfs>/split_huge_pages_in_range_pid >>> + * interface. >>> + */ >>> + >>> +#define _GNU_SOURCE >>> +#include <stdio.h> >>> +#include <stdlib.h> >>> +#include "numa.h" >>> +#include <unistd.h> >>> +#include <errno.h> >>> +#include <inttypes.h> >>> +#include <string.h> >>> +#include <sys/types.h> >>> +#include <sys/stat.h> >>> +#include <fcntl.h> >>> +#include <sys/mman.h> >>> +#include <sys/time.h> >>> +#include <sys/wait.h> >>> +#include <malloc.h> >>> +#include <stdbool.h> >>> + >>> +uint64_t pagesize; >>> +unsigned int pageshift; >>> +uint64_t pmd_pagesize; >>> + >>> +#define PMD_SIZE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size" >>> +#define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages_in_range_pid" >>> +#define SMAP_PATH "/proc/self/smaps" >>> +#define INPUT_MAX 80 >>> + >>> +#define PFN_MASK ((1UL<<55)-1) >>> +#define KPF_THP (1UL<<22) >>> + >>> +int is_backed_by_thp(char *vaddr, int pagemap_file, int kpageflags_file) >>> +{ >>> + uint64_t paddr; >>> + uint64_t page_flags; >>> + >>> + if (pagemap_file) { >>> + pread(pagemap_file, &paddr, sizeof(paddr), >>> + ((long)vaddr >> pageshift) * sizeof(paddr)); >>> + >>> + if (kpageflags_file) { >>> + pread(kpageflags_file, &page_flags, sizeof(page_flags), >>> + (paddr & PFN_MASK) * sizeof(page_flags)); >>> + >>> + return !!(page_flags & KPF_THP); >>> + } >>> + } >>> + return 0; >>> +} >>> + >>> + >>> +static uint64_t read_pmd_pagesize(void) >>> +{ >>> + int fd; >>> + char buf[20]; >>> + ssize_t num_read; >>> + >>> + fd = open(PMD_SIZE_PATH, O_RDONLY); >>> + if (fd == -1) { >>> + perror("Open hpage_pmd_size failed"); >>> + exit(EXIT_FAILURE); >>> + } >>> + num_read = read(fd, buf, 19); >>> + if (num_read < 1) { >>> + close(fd); >>> + perror("Read hpage_pmd_size failed"); >>> + exit(EXIT_FAILURE); >>> + } >>> + buf[num_read] = '\0'; >>> + close(fd); >>> + >>> + return strtoul(buf, NULL, 10); >>> +} >>> + >>> +static int write_file(const char *path, const char *buf, size_t buflen) >>> +{ >>> + int fd; >>> + ssize_t numwritten; >>> + >>> + fd = open(path, O_WRONLY); >>> + if (fd == -1) >>> + return 0; >>> + >>> + numwritten = write(fd, buf, buflen - 1); >>> + close(fd); >>> + if (numwritten < 1) >>> + return 0; >>> + >>> + return (unsigned int) numwritten; >>> +} >>> + >>> +static void write_debugfs(int pid, uint64_t vaddr_start, uint64_t vaddr_end) >>> +{ >>> + char input[INPUT_MAX]; >>> + int ret; >>> + >>> + ret = snprintf(input, INPUT_MAX, "%d,0x%lx,0x%lx", pid, vaddr_start, >>> + vaddr_end); >>> + if (ret >= INPUT_MAX) { >>> + printf("%s: Debugfs input is too long\n", __func__); >>> + exit(EXIT_FAILURE); >>> + } >>> + >>> + if (!write_file(SPLIT_DEBUGFS, input, ret + 1)) { >>> + perror(SPLIT_DEBUGFS); >>> + exit(EXIT_FAILURE); >>> + } >>> +} >>> + >>> +#define MAX_LINE_LENGTH 500 >>> + >>> +static bool check_for_pattern(FILE *fp, const char *pattern, char *buf) >>> +{ >>> + while (fgets(buf, MAX_LINE_LENGTH, fp) != NULL) { >>> + if (!strncmp(buf, pattern, strlen(pattern))) >>> + return true; >>> + } >>> + return false; >>> +} >>> + >>> +static uint64_t check_huge(void *addr) >>> +{ >>> + uint64_t thp = 0; >>> + int ret; >>> + FILE *fp; >>> + char buffer[MAX_LINE_LENGTH]; >>> + char addr_pattern[MAX_LINE_LENGTH]; >>> + >>> + ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-", >>> + (unsigned long) addr); >>> + if (ret >= MAX_LINE_LENGTH) { >>> + printf("%s: Pattern is too long\n", __func__); >>> + exit(EXIT_FAILURE); >>> + } >>> + >>> + >>> + fp = fopen(SMAP_PATH, "r"); >>> + if (!fp) { >>> + printf("%s: Failed to open file %s\n", __func__, SMAP_PATH); >>> + exit(EXIT_FAILURE); >>> + } >>> + if (!check_for_pattern(fp, addr_pattern, buffer)) >>> + goto err_out; >>> + >>> + /* >>> + * Fetch the AnonHugePages: in the same block and check the number of >>> + * hugepages. >>> + */ >>> + if (!check_for_pattern(fp, "AnonHugePages:", buffer)) >>> + goto err_out; >>> + >>> + if (sscanf(buffer, "AnonHugePages:%10ld kB", &thp) != 1) { >>> + printf("Reading smap error\n"); >>> + exit(EXIT_FAILURE); >>> + } >>> + >>> +err_out: >>> + fclose(fp); >>> + return thp; >>> +} >>> + >>> +void split_pmd_thp(void) >>> +{ >>> + char *one_page; >>> + size_t len = 4 * pmd_pagesize; >>> + uint64_t thp_size; >>> + size_t i; >>> + >>> + one_page = memalign(pmd_pagesize, len); >>> + >>> + madvise(one_page, len, MADV_HUGEPAGE); >>> + >>> + for (i = 0; i < len; i++) >>> + one_page[i] = (char)i; >>> + >>> + thp_size = check_huge(one_page); >>> + if (!thp_size) { >>> + printf("No THP is allocatd"); >>> + exit(EXIT_FAILURE); >>> + } >>> + >>> + /* split all possible huge pages */ >>> + write_debugfs(getpid(), (uint64_t)one_page, (uint64_t)one_page + len); >>> + >>> + for (i = 0; i < len; i++) >>> + if (one_page[i] != (char)i) { >>> + printf("%ld byte corrupted\n", i); >>> + exit(EXIT_FAILURE); >>> + } >>> + >>> + >>> + thp_size = check_huge(one_page); >>> + if (thp_size) { >>> + printf("Still %ld kB AnonHugePages not split\n", thp_size); >>> + exit(EXIT_FAILURE); >>> + } >>> + >>> + printf("Split huge pages successful\n"); >>> + free(one_page); >>> +} >>> + >>> +void split_pte_mapped_thp(void) >>> +{ >>> + char *one_page, *pte_mapped, *pte_mapped2; >>> + size_t len = 4 * pmd_pagesize; >>> + uint64_t thp_size; >>> + size_t i; >>> + const char *pagemap_template = "/proc/%d/pagemap"; >>> + const char *kpageflags_proc = "/proc/kpageflags"; >>> + char pagemap_proc[255]; >>> + int pagemap_fd; >>> + int kpageflags_fd; >>> + >>> + if (snprintf(pagemap_proc, 255, pagemap_template, getpid()) < 0) { >>> + perror("get pagemap proc error"); >>> + exit(EXIT_FAILURE); >>> + } >>> + pagemap_fd = open(pagemap_proc, O_RDONLY); >>> + >>> + if (pagemap_fd == -1) { >>> + perror("read pagemap:"); >>> + exit(EXIT_FAILURE); >>> + } >>> + >>> + kpageflags_fd = open(kpageflags_proc, O_RDONLY); >>> + >>> + if (kpageflags_fd == -1) { >>> + perror("read kpageflags:"); >>> + exit(EXIT_FAILURE); >>> + } >>> + >>> + one_page = mmap((void *)(1UL << 30), len, PROT_READ | PROT_WRITE, >>> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); >>> + >>> + madvise(one_page, len, MADV_HUGEPAGE); >>> + >>> + for (i = 0; i < len; i++) >>> + one_page[i] = (char)i; >>> + >>> + thp_size = check_huge(one_page); >>> + if (!thp_size) { >>> + printf("No THP is allocatd"); >>> + exit(EXIT_FAILURE); >>> + } >>> + >>> + pte_mapped = mremap(one_page, pagesize, pagesize, MREMAP_MAYMOVE); >>> + >>> + for (i = 1; i < 4; i++) { >>> + pte_mapped2 = mremap(one_page + pmd_pagesize * i + pagesize * i, >>> + pagesize, pagesize, >>> + MREMAP_MAYMOVE|MREMAP_FIXED, >>> + pte_mapped + pagesize * i); >>> + if (pte_mapped2 == (char *)-1) { >>> + perror("mremap failed"); >>> + exit(EXIT_FAILURE); >>> + } >>> + } >>> + >>> + /* smap does not show THPs after mremap, use kpageflags instead */ >>> + thp_size = 0; >>> + for (i = 0; i < pagesize * 4; i++) >>> + if (i % pagesize == 0 && >>> + is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd)) >>> + thp_size++; >>> + >>> + if (thp_size != 4) { >>> + printf("Some THPs are missing during mremap\n"); >>> + exit(EXIT_FAILURE); >>> + } >>> + >>> + /* split all possible huge pages */ >>> + write_debugfs(getpid(), (uint64_t)pte_mapped, >>> + (uint64_t)pte_mapped + pagesize * 4); >>> + >>> + /* smap does not show THPs after mremap, use kpageflags instead */ >>> + thp_size = 0; >>> + for (i = 0; i < pagesize * 4; i++) { >>> + if (pte_mapped[i] != (char)i) { >>> + printf("%ld byte corrupted\n", i); >>> + exit(EXIT_FAILURE); >>> + } >>> + if (i % pagesize == 0 && >>> + is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd)) >>> + thp_size++; >>> + } >>> + >>> + if (thp_size) { >>> + printf("Still %ld THPs not split\n", thp_size); >>> + exit(EXIT_FAILURE); >>> + } >>> + >>> + printf("Split PTE-mapped huge pages successful\n"); >>> + munmap(one_page, len); >>> + close(pagemap_fd); >>> + close(kpageflags_fd); >>> +} >>> + >>> +int main(int argc, char **argv) >>> +{ >>> + if (geteuid() != 0) { >>> + printf("Please run the benchmark as root\n"); >>> + exit(EXIT_FAILURE); >>> + } >>> + >>> + pagesize = getpagesize(); >>> + pageshift = ffs(pagesize) - 1; >>> + pmd_pagesize = read_pmd_pagesize(); >>> + >>> + split_pmd_thp(); >>> + split_pte_mapped_thp(); >>> + >>> + return 0; >>> +} >> — Best Regards, Yan Zi

4 years, 3 months

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[RFC PATCH v2 00/13] Add futex2 syscall

by André Almeida

Hi, This patch series introduces the futex2 syscalls. * What happened to the current futex()? For some years now, developers have been trying to add new features to futex, but maintainers have been reluctant to accept then, given the multiplexed interface full of legacy features and tricky to do big changes. Some problems that people tried to address with patchsets are: NUMA-awareness[0], smaller sized futexes[1], wait on multiple futexes[2]. NUMA, for instance, just doesn't fit the current API in a reasonable way. Considering that, it's not possible to merge new features into the current futex. ** The NUMA problem At the current implementation, all futex kernel side infrastructure is stored on a single node. Given that, all futex() calls issued by processors that aren't located on that node will have a memory access penalty when doing it. ** The 32bit sized futex problem Embedded systems or anything with memory constrains would benefit of using smaller sizes for the futex userspace integer. Also, a mutex implementation can be done using just three values, so 8 bits is enough for various scenarios. ** The wait on multiple problem The use case lies in the Wine implementation of the Windows NT interface WaitMultipleObjects. This Windows API function allows a thread to sleep waiting on the first of a set of event sources (mutexes, timers, signal, console input, etc) to signal. Considering this is a primitive synchronization operation for Windows applications, being able to quickly signal events on the producer side, and quickly go to sleep on the consumer side is essential for good performance of those running over Wine. [0] https://lore.kernel.org/lkml/20160505204230.932454245@linutronix.de/ [1] https://lore.kernel.org/lkml/20191221155659.3159-2-malteskarupke@web.de/ [2] https://lore.kernel.org/lkml/20200213214525.183689-1-andrealmeid@collabora.… * The solution As proposed by Peter Zijlstra and Florian Weimer[3], a new interface is required to solve this, which must be designed with those features in mind. futex2() is that interface. As opposed to the current multiplexed interface, the new one should have one syscall per operation. This will allow the maintainability of the API if it gets extended, and will help users with type checking of arguments. In particular, the new interface is extended to support the ability to wait on any of a list of futexes at a time, which could be seen as a vectored extension of the FUTEX_WAIT semantics. [3] https://lore.kernel.org/lkml/20200303120050.GC2596@hirez.programming.kicks-… * The interface The new interface can be seen in details in the following patches, but this is a high level summary of what the interface can do: - Supports wake/wait semantics, as in futex() - Supports requeue operations, similarly as FUTEX_CMP_REQUEUE, but with individual flags for each address - Supports waiting for a vector of futexes, using a new syscall named futex_waitv() - Supports variable sized futexes (8bits, 16bits and 32bits) - Supports NUMA-awareness operations, where the user can specify on which memory node would like to operate * Implementation The internal implementation follows a similar design to the original futex. Given that we want to replicate the same external behavior of current futex, this should be somewhat expected. For some functions, like the init and the code to get a shared key, I literally copied code and comments from kernel/futex.c. I decided to do so instead of exposing the original function as a public function since in that way we can freely modify our implementation if required, without any impact on old futex. Also, the comments precisely describes the details and corner cases of the implementation. Each patch contains a brief description of implementation, but patch 6 "docs: locking: futex2: Add documentation" adds a more complete document about it. * The patchset This patchset can be also found at my git tree: https://gitlab.collabora.com/tonyk/linux/-/tree/futex2-dev - Patch 1: Implements wait/wake, and the basics foundations of futex2 - Patches 2-4: Implement the remaining features (shared, waitv, requeue). - Patch 5: Adds the x86_x32 ABI handling. I kept it in a separated patch since I'm not sure if x86_x32 is still a thing, or if it should return -ENOSYS. - Patch 6: Add a documentation file which details the interface and the internal implementation. - Patches 7-13: Selftests for all operations along with perf support for futex2. - Patch 14: While working on porting glibc for futex2, I found out that there's a futex_wake() call at the user thread exit path, if that thread was created with clone(..., CLONE_CHILD_SETTID, ...). In order to make pthreads work with futex2, it was required to add this patch. Note that this is more a proof-of-concept of what we will need to do in future, rather than part of the interface and shouldn't be merged as it is. * Testing: This patchset provides selftests for each operation and their flags. Along with that, the following work was done: ** Stability To stress the interface in "real world scenarios": - glibc[4]: nptl's low level locking was modified to use futex2 API (except for robust and PI things). All relevant nptl/ tests passed. - Wine[5]: Proton/Wine was modified in order to use futex2() for the emulation of Windows NT sync mechanisms based on futex, called "fsync". Triple-A games with huge CPU's loads and tons of parallel jobs worked as expected when compared with the previous FUTEX_WAIT_MULTIPLE implementation at futex(). Some games issue 42k futex2() calls per second. - Full GNU/Linux distro: I installed the modified glibc in my host machine, so all pthread's programs would use futex2(). After tweaking systemd[6] to allow futex2() calls at seccomp, everything worked as expected (web browsers do some syscall sandboxing and need some configuration as well). - perf: The perf benchmarks tests can also be used to stress the interface, and they can be found in this patchset. ** Performance - For comparing futex() and futex2() performance, I used the artificial benchmarks implemented at perf (wake, wake-parallel, hash and requeue). The setup was 200 runs for each test and using 8, 80, 800, 8000 for the number of threads, Note that for this test, I'm not using patch 14 ("kernel: Enable waitpid() for futex2") , for reasons explained at "The patchset" section. - For the first three ones, I measured an average of 4% gain in performance. This is not a big step, but it shows that the new interface is at least comparable in performance with the current one. - For requeue, I measured an average of 21% decrease in performance compared to the original futex implementation. This is expected given the new design with individual flags. The performance trade-offs are explained at patch 4 ("futex2: Implement requeue operation"). [4] https://gitlab.collabora.com/tonyk/glibc/-/tree/futex2 [5] https://gitlab.collabora.com/tonyk/wine/-/tree/proton_5.13 [6] https://gitlab.collabora.com/tonyk/systemd * FAQ ** "Where's the code for NUMA and FUTEX_8/16?" The current code is already complex enough to take some time for review, so I believe it's better to split that work out to a future iteration of this patchset. Besides that, this RFC is the core part of the infrastructure, and the following features will not pose big design changes to it, the work will be more about wiring up the flags and modifying some functions. ** "And what's about FUTEX_64?" By supporting 64 bit futexes, the kernel structure for futex would need to have a 64 bit field for the value, and that could defeat one of the purposes of having different sized futexes in the first place: supporting smaller ones to decrease memory usage. This might be something that could be disabled for 32bit archs (and even for CONFIG_BASE_SMALL). Which use case would benefit for FUTEX_64? Does it worth the trade-offs? ** "Where's the PI/robust stuff?" As said by Peter Zijlstra at [3], all those new features are related to the "simple" futex interface, that doesn't use PI or robust. Do we want to have this complexity at futex2() and if so, should it be part of this patchset or can it be future work? Thanks, André * Changelog Changes from v1: - Unified futex_set_timer_and_wait and __futex_wait code - Dropped _carefull from linked list function calls - Fixed typos on docs patch - uAPI flags are now added as features are introduced, instead of all flags in patch 1 - Removed struct futex_single_waiter in favor of an anon struct v1: https://lore.kernel.org/lkml/20210215152404.250281-1-andrealmeid@collabora.… André Almeida (13): futex2: Implement wait and wake functions futex2: Add support for shared futexes futex2: Implement vectorized wait futex2: Implement requeue operation futex2: Add compatibility entry point for x86_x32 ABI docs: locking: futex2: Add documentation selftests: futex2: Add wake/wait test selftests: futex2: Add timeout test selftests: futex2: Add wouldblock test selftests: futex2: Add waitv test selftests: futex2: Add requeue test perf bench: Add futex2 benchmark tests kernel: Enable waitpid() for futex2 Documentation/locking/futex2.rst | 198 +++ Documentation/locking/index.rst | 1 + MAINTAINERS | 2 +- arch/arm/tools/syscall.tbl | 4 + arch/arm64/include/asm/unistd.h | 2 +- arch/arm64/include/asm/unistd32.h | 8 + arch/x86/entry/syscalls/syscall_32.tbl | 4 + arch/x86/entry/syscalls/syscall_64.tbl | 4 + fs/inode.c | 1 + include/linux/compat.h | 23 + include/linux/fs.h | 1 + include/linux/syscalls.h | 18 + include/uapi/asm-generic/unistd.h | 14 +- include/uapi/linux/futex.h | 31 + init/Kconfig | 7 + kernel/Makefile | 1 + kernel/fork.c | 2 + kernel/futex2.c | 1239 +++++++++++++++++ kernel/sys_ni.c | 6 + tools/arch/x86/include/asm/unistd_64.h | 12 + tools/include/uapi/asm-generic/unistd.h | 11 +- .../arch/x86/entry/syscalls/syscall_64.tbl | 4 + tools/perf/bench/bench.h | 4 + tools/perf/bench/futex-hash.c | 24 +- tools/perf/bench/futex-requeue.c | 57 +- tools/perf/bench/futex-wake-parallel.c | 41 +- tools/perf/bench/futex-wake.c | 37 +- tools/perf/bench/futex.h | 47 + tools/perf/builtin-bench.c | 18 +- .../selftests/futex/functional/.gitignore | 3 + .../selftests/futex/functional/Makefile | 8 +- .../futex/functional/futex2_requeue.c | 164 +++ .../selftests/futex/functional/futex2_wait.c | 209 +++ .../selftests/futex/functional/futex2_waitv.c | 157 +++ .../futex/functional/futex_wait_timeout.c | 58 +- .../futex/functional/futex_wait_wouldblock.c | 33 +- .../testing/selftests/futex/functional/run.sh | 6 + .../selftests/futex/include/futex2test.h | 121 ++ 38 files changed, 2527 insertions(+), 53 deletions(-) create mode 100644 Documentation/locking/futex2.rst create mode 100644 kernel/futex2.c create mode 100644 tools/testing/selftests/futex/functional/futex2_requeue.c create mode 100644 tools/testing/selftests/futex/functional/futex2_wait.c create mode 100644 tools/testing/selftests/futex/functional/futex2_waitv.c create mode 100644 tools/testing/selftests/futex/include/futex2test.h -- 2.30.1

4 years, 3 months

7
26
0 0

[PATCH AUTOSEL 5.11 04/12] selftests: kvm: Mmap the entire vcpu mmap area

by Sasha Levin

From: Aaron Lewis <aaronlewis(a)google.com> [ Upstream commit 6528fc0a11de3d16339cf17639e2f69a68fcaf4d ] The vcpu mmap area may consist of more than just the kvm_run struct. Allocate enough space for the entire vcpu mmap area. Without this, on x86, the PIO page, for example, will be missing. This is problematic when dealing with an unhandled exception from the guest as the exception vector will be incorrectly reported as 0x0. Message-Id: <20210210165035.3712489-1-aaronlewis(a)google.com> Reviewed-by: Andrew Jones <drjones(a)redhat.com> Co-developed-by: Steve Rutherford <srutherford(a)google.com> Signed-off-by: Aaron Lewis <aaronlewis(a)google.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/kvm/lib/kvm_util.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index fa5a90e6c6f0..859a0b57c683 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -21,6 +21,8 @@ #define KVM_UTIL_PGS_PER_HUGEPG 512 #define KVM_UTIL_MIN_PFN 2 +static int vcpu_mmap_sz(void); + /* Aligns x up to the next multiple of size. Size must be a power of 2. */ static void *align(void *x, size_t size) { @@ -509,7 +511,7 @@ static void vm_vcpu_rm(struct kvm_vm *vm, struct vcpu *vcpu) vcpu->dirty_gfns = NULL; } - ret = munmap(vcpu->state, sizeof(*vcpu->state)); + ret = munmap(vcpu->state, vcpu_mmap_sz()); TEST_ASSERT(ret == 0, "munmap of VCPU fd failed, rc: %i " "errno: %i", ret, errno); close(vcpu->fd); @@ -978,7 +980,7 @@ void vm_vcpu_add(struct kvm_vm *vm, uint32_t vcpuid) TEST_ASSERT(vcpu_mmap_sz() >= sizeof(*vcpu->state), "vcpu mmap size " "smaller than expected, vcpu_mmap_sz: %i expected_min: %zi", vcpu_mmap_sz(), sizeof(*vcpu->state)); - vcpu->state = (struct kvm_run *) mmap(NULL, sizeof(*vcpu->state), + vcpu->state = (struct kvm_run *) mmap(NULL, vcpu_mmap_sz(), PROT_READ | PROT_WRITE, MAP_SHARED, vcpu->fd, 0); TEST_ASSERT(vcpu->state != MAP_FAILED, "mmap vcpu_state failed, " "vcpu id: %u errno: %i", vcpuid, errno); -- 2.30.1

4 years, 3 months

1
0
0 0

[PATCH] selftest/net/ipsec.c: Remove unneeded semicolon

by Xu Wang

fix semicolon.cocci warning: tools/testing/selftests/net/ipsec.c:1788:2-3: Unneeded semicolon Signed-off-by: Xu Wang <vulab(a)iscas.ac.cn> --- tools/testing/selftests/net/ipsec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/net/ipsec.c b/tools/testing/selftests/net/ipsec.c index 17ced7d6ce25..f23438d512c5 100644 --- a/tools/testing/selftests/net/ipsec.c +++ b/tools/testing/selftests/net/ipsec.c @@ -1785,7 +1785,7 @@ static void grand_child_serv(unsigned int nr, int cmd_fd, void *buf, break; default: printk("got unknown msg type %d", msg->type); - }; + } } static int grand_child_f(unsigned int nr, int cmd_fd, void *buf) -- 2.17.1

4 years, 3 months

2
1
0 0

[PATCH] selftests: timers: set-timer-lat: remove unneeded semicolon

by Jiapeng Chong

Fix the following coccicheck warnings: ./tools/testing/selftests/timers/set-timer-lat.c:83:2-3: Unneeded semicolon. Reported-by: Abaci Robot <abaci(a)linux.alibaba.com> Signed-off-by: Jiapeng Chong <jiapeng.chong(a)linux.alibaba.com> --- tools/testing/selftests/timers/set-timer-lat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/timers/set-timer-lat.c b/tools/testing/selftests/timers/set-timer-lat.c index 50da454..d60bbca 100644 --- a/tools/testing/selftests/timers/set-timer-lat.c +++ b/tools/testing/selftests/timers/set-timer-lat.c @@ -80,7 +80,7 @@ char *clockstring(int clockid) return "CLOCK_BOOTTIME_ALARM"; case CLOCK_TAI: return "CLOCK_TAI"; - }; + } return "UNKNOWN_CLOCKID"; } -- 1.8.3.1

4 years, 3 months

1
0
0 0

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