mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-29 23:24:11 +08:00
userfaultfd: selftest
This test allocates two virtual areas and bounces the physical memory across the two virtual areas using only userfaultfd. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Shuah Khan <shuah.kh@samsung.com> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrea Arcangeli
Linus Torvalds
parent
2c5b7e1be7
commit
c47174fc36
@ -8,10 +8,13 @@ BINARIES += hugetlbfstest
|
||||
BINARIES += map_hugetlb
|
||||
BINARIES += thuge-gen
|
||||
BINARIES += transhuge-stress
|
||||
BINARIES += userfaultfd
|
||||
|
||||
all: $(BINARIES)
|
||||
%: %.c
|
||||
$(CC) $(CFLAGS) -o $@ $^ -lrt
|
||||
userfaultfd: userfaultfd.c
|
||||
$(CC) $(CFLAGS) -O2 -o $@ $^ -lpthread
|
||||
|
||||
TEST_PROGS := run_vmtests
|
||||
TEST_FILES := $(BINARIES)
|
||||
|
||||
@ -86,6 +86,17 @@ else
|
||||
echo "[PASS]"
|
||||
fi
|
||||
|
||||
echo "--------------------"
|
||||
echo "running userfaultfd"
|
||||
echo "--------------------"
|
||||
./userfaultfd 128 32
|
||||
if [ $? -ne 0 ]; then
|
||||
echo "[FAIL]"
|
||||
exitcode=1
|
||||
else
|
||||
echo "[PASS]"
|
||||
fi
|
||||
|
||||
#cleanup
|
||||
umount $mnt
|
||||
rm -rf $mnt
|
||||
|
||||
636
tools/testing/selftests/vm/userfaultfd.c
Normal file
636
tools/testing/selftests/vm/userfaultfd.c
Normal file
@ -0,0 +1,636 @@
|
||||
/*
|
||||
* Stress userfaultfd syscall.
|
||||
*
|
||||
* Copyright (C) 2015 Red Hat, Inc.
|
||||
*
|
||||
* This work is licensed under the terms of the GNU GPL, version 2. See
|
||||
* the COPYING file in the top-level directory.
|
||||
*
|
||||
* This test allocates two virtual areas and bounces the physical
|
||||
* memory across the two virtual areas (from area_src to area_dst)
|
||||
* using userfaultfd.
|
||||
*
|
||||
* There are three threads running per CPU:
|
||||
*
|
||||
* 1) one per-CPU thread takes a per-page pthread_mutex in a random
|
||||
* page of the area_dst (while the physical page may still be in
|
||||
* area_src), and increments a per-page counter in the same page,
|
||||
* and checks its value against a verification region.
|
||||
*
|
||||
* 2) another per-CPU thread handles the userfaults generated by
|
||||
* thread 1 above. userfaultfd blocking reads or poll() modes are
|
||||
* exercised interleaved.
|
||||
*
|
||||
* 3) one last per-CPU thread transfers the memory in the background
|
||||
* at maximum bandwidth (if not already transferred by thread
|
||||
* 2). Each cpu thread takes cares of transferring a portion of the
|
||||
* area.
|
||||
*
|
||||
* When all threads of type 3 completed the transfer, one bounce is
|
||||
* complete. area_src and area_dst are then swapped. All threads are
|
||||
* respawned and so the bounce is immediately restarted in the
|
||||
* opposite direction.
|
||||
*
|
||||
* per-CPU threads 1 by triggering userfaults inside
|
||||
* pthread_mutex_lock will also verify the atomicity of the memory
|
||||
* transfer (UFFDIO_COPY).
|
||||
*
|
||||
* The program takes two parameters: the amounts of physical memory in
|
||||
* megabytes (MiB) of the area and the number of bounces to execute.
|
||||
*
|
||||
* # 100MiB 99999 bounces
|
||||
* ./userfaultfd 100 99999
|
||||
*
|
||||
* # 1GiB 99 bounces
|
||||
* ./userfaultfd 1000 99
|
||||
*
|
||||
* # 10MiB-~6GiB 999 bounces, continue forever unless an error triggers
|
||||
* while ./userfaultfd $[RANDOM % 6000 + 10] 999; do true; done
|
||||
*/
|
||||
|
||||
#define _GNU_SOURCE
|
||||
#include <stdio.h>
|
||||
#include <errno.h>
|
||||
#include <unistd.h>
|
||||
#include <stdlib.h>
|
||||
#include <sys/types.h>
|
||||
#include <sys/stat.h>
|
||||
#include <fcntl.h>
|
||||
#include <time.h>
|
||||
#include <signal.h>
|
||||
#include <poll.h>
|
||||
#include <string.h>
|
||||
#include <sys/mman.h>
|
||||
#include <sys/syscall.h>
|
||||
#include <sys/ioctl.h>
|
||||
#include <pthread.h>
|
||||
#include "../../../../include/uapi/linux/userfaultfd.h"
|
||||
|
||||
#ifdef __x86_64__
|
||||
#define __NR_userfaultfd 323
|
||||
#elif defined(__i386__)
|
||||
#define __NR_userfaultfd 359
|
||||
#elif defined(__powewrpc__)
|
||||
#define __NR_userfaultfd 364
|
||||
#else
|
||||
#error "missing __NR_userfaultfd definition"
|
||||
#endif
|
||||
|
||||
static unsigned long nr_cpus, nr_pages, nr_pages_per_cpu, page_size;
|
||||
|
||||
#define BOUNCE_RANDOM (1<<0)
|
||||
#define BOUNCE_RACINGFAULTS (1<<1)
|
||||
#define BOUNCE_VERIFY (1<<2)
|
||||
#define BOUNCE_POLL (1<<3)
|
||||
static int bounces;
|
||||
|
||||
static unsigned long long *count_verify;
|
||||
static int uffd, finished, *pipefd;
|
||||
static char *area_src, *area_dst;
|
||||
static char *zeropage;
|
||||
pthread_attr_t attr;
|
||||
|
||||
/* pthread_mutex_t starts at page offset 0 */
|
||||
#define area_mutex(___area, ___nr) \
|
||||
((pthread_mutex_t *) ((___area) + (___nr)*page_size))
|
||||
/*
|
||||
* count is placed in the page after pthread_mutex_t naturally aligned
|
||||
* to avoid non alignment faults on non-x86 archs.
|
||||
*/
|
||||
#define area_count(___area, ___nr) \
|
||||
((volatile unsigned long long *) ((unsigned long) \
|
||||
((___area) + (___nr)*page_size + \
|
||||
sizeof(pthread_mutex_t) + \
|
||||
sizeof(unsigned long long) - 1) & \
|
||||
~(unsigned long)(sizeof(unsigned long long) \
|
||||
- 1)))
|
||||
|
||||
static int my_bcmp(char *str1, char *str2, size_t n)
|
||||
{
|
||||
unsigned long i;
|
||||
for (i = 0; i < n; i++)
|
||||
if (str1[i] != str2[i])
|
||||
return 1;
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void *locking_thread(void *arg)
|
||||
{
|
||||
unsigned long cpu = (unsigned long) arg;
|
||||
struct random_data rand;
|
||||
unsigned long page_nr = *(&(page_nr)); /* uninitialized warning */
|
||||
int32_t rand_nr;
|
||||
unsigned long long count;
|
||||
char randstate[64];
|
||||
unsigned int seed;
|
||||
time_t start;
|
||||
|
||||
if (bounces & BOUNCE_RANDOM) {
|
||||
seed = (unsigned int) time(NULL) - bounces;
|
||||
if (!(bounces & BOUNCE_RACINGFAULTS))
|
||||
seed += cpu;
|
||||
bzero(&rand, sizeof(rand));
|
||||
bzero(&randstate, sizeof(randstate));
|
||||
if (initstate_r(seed, randstate, sizeof(randstate), &rand))
|
||||
fprintf(stderr, "srandom_r error\n"), exit(1);
|
||||
} else {
|
||||
page_nr = -bounces;
|
||||
if (!(bounces & BOUNCE_RACINGFAULTS))
|
||||
page_nr += cpu * nr_pages_per_cpu;
|
||||
}
|
||||
|
||||
while (!finished) {
|
||||
if (bounces & BOUNCE_RANDOM) {
|
||||
if (random_r(&rand, &rand_nr))
|
||||
fprintf(stderr, "random_r 1 error\n"), exit(1);
|
||||
page_nr = rand_nr;
|
||||
if (sizeof(page_nr) > sizeof(rand_nr)) {
|
||||
if (random_r(&rand, &rand_nr))
|
||||
fprintf(stderr, "random_r 2 error\n"), exit(1);
|
||||
page_nr |= ((unsigned long) rand_nr) << 32;
|
||||
}
|
||||
} else
|
||||
page_nr += 1;
|
||||
page_nr %= nr_pages;
|
||||
|
||||
start = time(NULL);
|
||||
if (bounces & BOUNCE_VERIFY) {
|
||||
count = *area_count(area_dst, page_nr);
|
||||
if (!count)
|
||||
fprintf(stderr,
|
||||
"page_nr %lu wrong count %Lu %Lu\n",
|
||||
page_nr, count,
|
||||
count_verify[page_nr]), exit(1);
|
||||
|
||||
|
||||
/*
|
||||
* We can't use bcmp (or memcmp) because that
|
||||
* returns 0 erroneously if the memory is
|
||||
* changing under it (even if the end of the
|
||||
* page is never changing and always
|
||||
* different).
|
||||
*/
|
||||
#if 1
|
||||
if (!my_bcmp(area_dst + page_nr * page_size, zeropage,
|
||||
page_size))
|
||||
fprintf(stderr,
|
||||
"my_bcmp page_nr %lu wrong count %Lu %Lu\n",
|
||||
page_nr, count,
|
||||
count_verify[page_nr]), exit(1);
|
||||
#else
|
||||
unsigned long loops;
|
||||
|
||||
loops = 0;
|
||||
/* uncomment the below line to test with mutex */
|
||||
/* pthread_mutex_lock(area_mutex(area_dst, page_nr)); */
|
||||
while (!bcmp(area_dst + page_nr * page_size, zeropage,
|
||||
page_size)) {
|
||||
loops += 1;
|
||||
if (loops > 10)
|
||||
break;
|
||||
}
|
||||
/* uncomment below line to test with mutex */
|
||||
/* pthread_mutex_unlock(area_mutex(area_dst, page_nr)); */
|
||||
if (loops) {
|
||||
fprintf(stderr,
|
||||
"page_nr %lu all zero thread %lu %p %lu\n",
|
||||
page_nr, cpu, area_dst + page_nr * page_size,
|
||||
loops);
|
||||
if (loops > 10)
|
||||
exit(1);
|
||||
}
|
||||
#endif
|
||||
}
|
||||
|
||||
pthread_mutex_lock(area_mutex(area_dst, page_nr));
|
||||
count = *area_count(area_dst, page_nr);
|
||||
if (count != count_verify[page_nr]) {
|
||||
fprintf(stderr,
|
||||
"page_nr %lu memory corruption %Lu %Lu\n",
|
||||
page_nr, count,
|
||||
count_verify[page_nr]), exit(1);
|
||||
}
|
||||
count++;
|
||||
*area_count(area_dst, page_nr) = count_verify[page_nr] = count;
|
||||
pthread_mutex_unlock(area_mutex(area_dst, page_nr));
|
||||
|
||||
if (time(NULL) - start > 1)
|
||||
fprintf(stderr,
|
||||
"userfault too slow %ld "
|
||||
"possible false positive with overcommit\n",
|
||||
time(NULL) - start);
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static int copy_page(unsigned long offset)
|
||||
{
|
||||
struct uffdio_copy uffdio_copy;
|
||||
|
||||
if (offset >= nr_pages * page_size)
|
||||
fprintf(stderr, "unexpected offset %lu\n",
|
||||
offset), exit(1);
|
||||
uffdio_copy.dst = (unsigned long) area_dst + offset;
|
||||
uffdio_copy.src = (unsigned long) area_src + offset;
|
||||
uffdio_copy.len = page_size;
|
||||
uffdio_copy.mode = 0;
|
||||
uffdio_copy.copy = 0;
|
||||
if (ioctl(uffd, UFFDIO_COPY, &uffdio_copy)) {
|
||||
/* real retval in ufdio_copy.copy */
|
||||
if (uffdio_copy.copy != -EEXIST)
|
||||
fprintf(stderr, "UFFDIO_COPY error %Ld\n",
|
||||
uffdio_copy.copy), exit(1);
|
||||
} else if (uffdio_copy.copy != page_size) {
|
||||
fprintf(stderr, "UFFDIO_COPY unexpected copy %Ld\n",
|
||||
uffdio_copy.copy), exit(1);
|
||||
} else
|
||||
return 1;
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void *uffd_poll_thread(void *arg)
|
||||
{
|
||||
unsigned long cpu = (unsigned long) arg;
|
||||
struct pollfd pollfd[2];
|
||||
struct uffd_msg msg;
|
||||
int ret;
|
||||
unsigned long offset;
|
||||
char tmp_chr;
|
||||
unsigned long userfaults = 0;
|
||||
|
||||
pollfd[0].fd = uffd;
|
||||
pollfd[0].events = POLLIN;
|
||||
pollfd[1].fd = pipefd[cpu*2];
|
||||
pollfd[1].events = POLLIN;
|
||||
|
||||
for (;;) {
|
||||
ret = poll(pollfd, 2, -1);
|
||||
if (!ret)
|
||||
fprintf(stderr, "poll error %d\n", ret), exit(1);
|
||||
if (ret < 0)
|
||||
perror("poll"), exit(1);
|
||||
if (pollfd[1].revents & POLLIN) {
|
||||
if (read(pollfd[1].fd, &tmp_chr, 1) != 1)
|
||||
fprintf(stderr, "read pipefd error\n"),
|
||||
exit(1);
|
||||
break;
|
||||
}
|
||||
if (!(pollfd[0].revents & POLLIN))
|
||||
fprintf(stderr, "pollfd[0].revents %d\n",
|
||||
pollfd[0].revents), exit(1);
|
||||
ret = read(uffd, &msg, sizeof(msg));
|
||||
if (ret < 0) {
|
||||
if (errno == EAGAIN)
|
||||
continue;
|
||||
perror("nonblocking read error"), exit(1);
|
||||
}
|
||||
if (msg.event != UFFD_EVENT_PAGEFAULT)
|
||||
fprintf(stderr, "unexpected msg event %u\n",
|
||||
msg.event), exit(1);
|
||||
if (msg.arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
|
||||
fprintf(stderr, "unexpected write fault\n"), exit(1);
|
||||
offset = (char *)msg.arg.pagefault.address - area_dst;
|
||||
offset &= ~(page_size-1);
|
||||
if (copy_page(offset))
|
||||
userfaults++;
|
||||
}
|
||||
return (void *)userfaults;
|
||||
}
|
||||
|
||||
pthread_mutex_t uffd_read_mutex = PTHREAD_MUTEX_INITIALIZER;
|
||||
|
||||
static void *uffd_read_thread(void *arg)
|
||||
{
|
||||
unsigned long *this_cpu_userfaults;
|
||||
struct uffd_msg msg;
|
||||
unsigned long offset;
|
||||
int ret;
|
||||
|
||||
this_cpu_userfaults = (unsigned long *) arg;
|
||||
*this_cpu_userfaults = 0;
|
||||
|
||||
pthread_mutex_unlock(&uffd_read_mutex);
|
||||
/* from here cancellation is ok */
|
||||
|
||||
for (;;) {
|
||||
ret = read(uffd, &msg, sizeof(msg));
|
||||
if (ret != sizeof(msg)) {
|
||||
if (ret < 0)
|
||||
perror("blocking read error"), exit(1);
|
||||
else
|
||||
fprintf(stderr, "short read\n"), exit(1);
|
||||
}
|
||||
if (msg.event != UFFD_EVENT_PAGEFAULT)
|
||||
fprintf(stderr, "unexpected msg event %u\n",
|
||||
msg.event), exit(1);
|
||||
if (bounces & BOUNCE_VERIFY &&
|
||||
msg.arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
|
||||
fprintf(stderr, "unexpected write fault\n"), exit(1);
|
||||
offset = (char *)msg.arg.pagefault.address - area_dst;
|
||||
offset &= ~(page_size-1);
|
||||
if (copy_page(offset))
|
||||
(*this_cpu_userfaults)++;
|
||||
}
|
||||
return (void *)NULL;
|
||||
}
|
||||
|
||||
static void *background_thread(void *arg)
|
||||
{
|
||||
unsigned long cpu = (unsigned long) arg;
|
||||
unsigned long page_nr;
|
||||
|
||||
for (page_nr = cpu * nr_pages_per_cpu;
|
||||
page_nr < (cpu+1) * nr_pages_per_cpu;
|
||||
page_nr++)
|
||||
copy_page(page_nr * page_size);
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static int stress(unsigned long *userfaults)
|
||||
{
|
||||
unsigned long cpu;
|
||||
pthread_t locking_threads[nr_cpus];
|
||||
pthread_t uffd_threads[nr_cpus];
|
||||
pthread_t background_threads[nr_cpus];
|
||||
void **_userfaults = (void **) userfaults;
|
||||
|
||||
finished = 0;
|
||||
for (cpu = 0; cpu < nr_cpus; cpu++) {
|
||||
if (pthread_create(&locking_threads[cpu], &attr,
|
||||
locking_thread, (void *)cpu))
|
||||
return 1;
|
||||
if (bounces & BOUNCE_POLL) {
|
||||
if (pthread_create(&uffd_threads[cpu], &attr,
|
||||
uffd_poll_thread, (void *)cpu))
|
||||
return 1;
|
||||
} else {
|
||||
if (pthread_create(&uffd_threads[cpu], &attr,
|
||||
uffd_read_thread,
|
||||
&_userfaults[cpu]))
|
||||
return 1;
|
||||
pthread_mutex_lock(&uffd_read_mutex);
|
||||
}
|
||||
if (pthread_create(&background_threads[cpu], &attr,
|
||||
background_thread, (void *)cpu))
|
||||
return 1;
|
||||
}
|
||||
for (cpu = 0; cpu < nr_cpus; cpu++)
|
||||
if (pthread_join(background_threads[cpu], NULL))
|
||||
return 1;
|
||||
|
||||
/*
|
||||
* Be strict and immediately zap area_src, the whole area has
|
||||
* been transferred already by the background treads. The
|
||||
* area_src could then be faulted in in a racy way by still
|
||||
* running uffdio_threads reading zeropages after we zapped
|
||||
* area_src (but they're guaranteed to get -EEXIST from
|
||||
* UFFDIO_COPY without writing zero pages into area_dst
|
||||
* because the background threads already completed).
|
||||
*/
|
||||
if (madvise(area_src, nr_pages * page_size, MADV_DONTNEED)) {
|
||||
perror("madvise");
|
||||
return 1;
|
||||
}
|
||||
|
||||
for (cpu = 0; cpu < nr_cpus; cpu++) {
|
||||
char c;
|
||||
if (bounces & BOUNCE_POLL) {
|
||||
if (write(pipefd[cpu*2+1], &c, 1) != 1) {
|
||||
fprintf(stderr, "pipefd write error\n");
|
||||
return 1;
|
||||
}
|
||||
if (pthread_join(uffd_threads[cpu], &_userfaults[cpu]))
|
||||
return 1;
|
||||
} else {
|
||||
if (pthread_cancel(uffd_threads[cpu]))
|
||||
return 1;
|
||||
if (pthread_join(uffd_threads[cpu], NULL))
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
|
||||
finished = 1;
|
||||
for (cpu = 0; cpu < nr_cpus; cpu++)
|
||||
if (pthread_join(locking_threads[cpu], NULL))
|
||||
return 1;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int userfaultfd_stress(void)
|
||||
{
|
||||
void *area;
|
||||
char *tmp_area;
|
||||
unsigned long nr;
|
||||
struct uffdio_register uffdio_register;
|
||||
struct uffdio_api uffdio_api;
|
||||
unsigned long cpu;
|
||||
int uffd_flags;
|
||||
unsigned long userfaults[nr_cpus];
|
||||
|
||||
if (posix_memalign(&area, page_size, nr_pages * page_size)) {
|
||||
fprintf(stderr, "out of memory\n");
|
||||
return 1;
|
||||
}
|
||||
area_src = area;
|
||||
if (posix_memalign(&area, page_size, nr_pages * page_size)) {
|
||||
fprintf(stderr, "out of memory\n");
|
||||
return 1;
|
||||
}
|
||||
area_dst = area;
|
||||
|
||||
uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
|
||||
if (uffd < 0) {
|
||||
fprintf(stderr,
|
||||
"userfaultfd syscall not available in this kernel\n");
|
||||
return 1;
|
||||
}
|
||||
uffd_flags = fcntl(uffd, F_GETFD, NULL);
|
||||
|
||||
uffdio_api.api = UFFD_API;
|
||||
uffdio_api.features = 0;
|
||||
if (ioctl(uffd, UFFDIO_API, &uffdio_api)) {
|
||||
fprintf(stderr, "UFFDIO_API\n");
|
||||
return 1;
|
||||
}
|
||||
if (uffdio_api.api != UFFD_API) {
|
||||
fprintf(stderr, "UFFDIO_API error %Lu\n", uffdio_api.api);
|
||||
return 1;
|
||||
}
|
||||
|
||||
count_verify = malloc(nr_pages * sizeof(unsigned long long));
|
||||
if (!count_verify) {
|
||||
perror("count_verify");
|
||||
return 1;
|
||||
}
|
||||
|
||||
for (nr = 0; nr < nr_pages; nr++) {
|
||||
*area_mutex(area_src, nr) = (pthread_mutex_t)
|
||||
PTHREAD_MUTEX_INITIALIZER;
|
||||
count_verify[nr] = *area_count(area_src, nr) = 1;
|
||||
}
|
||||
|
||||
pipefd = malloc(sizeof(int) * nr_cpus * 2);
|
||||
if (!pipefd) {
|
||||
perror("pipefd");
|
||||
return 1;
|
||||
}
|
||||
for (cpu = 0; cpu < nr_cpus; cpu++) {
|
||||
if (pipe2(&pipefd[cpu*2], O_CLOEXEC | O_NONBLOCK)) {
|
||||
perror("pipe");
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
|
||||
if (posix_memalign(&area, page_size, page_size)) {
|
||||
fprintf(stderr, "out of memory\n");
|
||||
return 1;
|
||||
}
|
||||
zeropage = area;
|
||||
bzero(zeropage, page_size);
|
||||
|
||||
pthread_mutex_lock(&uffd_read_mutex);
|
||||
|
||||
pthread_attr_init(&attr);
|
||||
pthread_attr_setstacksize(&attr, 16*1024*1024);
|
||||
|
||||
while (bounces--) {
|
||||
unsigned long expected_ioctls;
|
||||
|
||||
printf("bounces: %d, mode:", bounces);
|
||||
if (bounces & BOUNCE_RANDOM)
|
||||
printf(" rnd");
|
||||
if (bounces & BOUNCE_RACINGFAULTS)
|
||||
printf(" racing");
|
||||
if (bounces & BOUNCE_VERIFY)
|
||||
printf(" ver");
|
||||
if (bounces & BOUNCE_POLL)
|
||||
printf(" poll");
|
||||
printf(", ");
|
||||
fflush(stdout);
|
||||
|
||||
if (bounces & BOUNCE_POLL)
|
||||
fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
|
||||
else
|
||||
fcntl(uffd, F_SETFL, uffd_flags & ~O_NONBLOCK);
|
||||
|
||||
/* register */
|
||||
uffdio_register.range.start = (unsigned long) area_dst;
|
||||
uffdio_register.range.len = nr_pages * page_size;
|
||||
uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
|
||||
if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
|
||||
fprintf(stderr, "register failure\n");
|
||||
return 1;
|
||||
}
|
||||
expected_ioctls = (1 << _UFFDIO_WAKE) |
|
||||
(1 << _UFFDIO_COPY) |
|
||||
(1 << _UFFDIO_ZEROPAGE);
|
||||
if ((uffdio_register.ioctls & expected_ioctls) !=
|
||||
expected_ioctls) {
|
||||
fprintf(stderr,
|
||||
"unexpected missing ioctl for anon memory\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* The madvise done previously isn't enough: some
|
||||
* uffd_thread could have read userfaults (one of
|
||||
* those already resolved by the background thread)
|
||||
* and it may be in the process of calling
|
||||
* UFFDIO_COPY. UFFDIO_COPY will read the zapped
|
||||
* area_src and it would map a zero page in it (of
|
||||
* course such a UFFDIO_COPY is perfectly safe as it'd
|
||||
* return -EEXIST). The problem comes at the next
|
||||
* bounce though: that racing UFFDIO_COPY would
|
||||
* generate zeropages in the area_src, so invalidating
|
||||
* the previous MADV_DONTNEED. Without this additional
|
||||
* MADV_DONTNEED those zeropages leftovers in the
|
||||
* area_src would lead to -EEXIST failure during the
|
||||
* next bounce, effectively leaving a zeropage in the
|
||||
* area_dst.
|
||||
*
|
||||
* Try to comment this out madvise to see the memory
|
||||
* corruption being caught pretty quick.
|
||||
*
|
||||
* khugepaged is also inhibited to collapse THP after
|
||||
* MADV_DONTNEED only after the UFFDIO_REGISTER, so it's
|
||||
* required to MADV_DONTNEED here.
|
||||
*/
|
||||
if (madvise(area_dst, nr_pages * page_size, MADV_DONTNEED)) {
|
||||
perror("madvise 2");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* bounce pass */
|
||||
if (stress(userfaults))
|
||||
return 1;
|
||||
|
||||
/* unregister */
|
||||
if (ioctl(uffd, UFFDIO_UNREGISTER, &uffdio_register.range)) {
|
||||
fprintf(stderr, "register failure\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* verification */
|
||||
if (bounces & BOUNCE_VERIFY) {
|
||||
for (nr = 0; nr < nr_pages; nr++) {
|
||||
if (my_bcmp(area_dst,
|
||||
area_dst + nr * page_size,
|
||||
sizeof(pthread_mutex_t))) {
|
||||
fprintf(stderr,
|
||||
"error mutex 2 %lu\n",
|
||||
nr);
|
||||
bounces = 0;
|
||||
}
|
||||
if (*area_count(area_dst, nr) != count_verify[nr]) {
|
||||
fprintf(stderr,
|
||||
"error area_count %Lu %Lu %lu\n",
|
||||
*area_count(area_src, nr),
|
||||
count_verify[nr],
|
||||
nr);
|
||||
bounces = 0;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/* prepare next bounce */
|
||||
tmp_area = area_src;
|
||||
area_src = area_dst;
|
||||
area_dst = tmp_area;
|
||||
|
||||
printf("userfaults:");
|
||||
for (cpu = 0; cpu < nr_cpus; cpu++)
|
||||
printf(" %lu", userfaults[cpu]);
|
||||
printf("\n");
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int main(int argc, char **argv)
|
||||
{
|
||||
if (argc < 3)
|
||||
fprintf(stderr, "Usage: <MiB> <bounces>\n"), exit(1);
|
||||
nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
|
||||
page_size = sysconf(_SC_PAGE_SIZE);
|
||||
if ((unsigned long) area_count(NULL, 0) + sizeof(unsigned long long) >
|
||||
page_size)
|
||||
fprintf(stderr, "Impossible to run this test\n"), exit(2);
|
||||
nr_pages_per_cpu = atol(argv[1]) * 1024*1024 / page_size /
|
||||
nr_cpus;
|
||||
if (!nr_pages_per_cpu) {
|
||||
fprintf(stderr, "invalid MiB\n");
|
||||
fprintf(stderr, "Usage: <MiB> <bounces>\n"), exit(1);
|
||||
}
|
||||
bounces = atoi(argv[2]);
|
||||
if (bounces <= 0) {
|
||||
fprintf(stderr, "invalid bounces\n");
|
||||
fprintf(stderr, "Usage: <MiB> <bounces>\n"), exit(1);
|
||||
}
|
||||
nr_pages = nr_pages_per_cpu * nr_cpus;
|
||||
printf("nr_pages: %lu, nr_pages_per_cpu: %lu\n",
|
||||
nr_pages, nr_pages_per_cpu);
|
||||
return userfaultfd_stress();
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user