Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1220816 > unrolled thread
| Started by | Eric B Munson <emunson@akamai.com> |
|---|---|
| First post | 2015-09-08 16:10 +0200 |
| Last post | 2015-09-08 16:10 +0200 |
| Articles | 2 — 1 participant |
Back to article view | Back to linux.kernel
[PATCH v9 0/6] Allow user to request memory to be locked on page fault Eric B Munson <emunson@akamai.com> - 2015-09-08 16:10 +0200
[PATCH v9 5/6] selftests: vm: Add tests for lock on fault Eric B Munson <emunson@akamai.com> - 2015-09-08 16:10 +0200
| From | Eric B Munson <emunson@akamai.com> |
|---|---|
| Date | 2015-09-08 16:10 +0200 |
| Subject | [PATCH v9 0/6] Allow user to request memory to be locked on page fault |
| Message-ID | <q6rBf-624-3@gated-at.bofh.it> |
Since this set has not been merge yet, here is a respin that drops the
export of VM_LOCKONFAULT to the rmap code.
---
mlock() allows a user to control page out of program memory, but this
comes at the cost of faulting in the entire mapping when it is
allocated. For large mappings where the entire area is not necessary
this is not ideal. Instead of forcing all locked pages to be present
when they are allocated, this set creates a middle ground. Pages are
marked to be placed on the unevictable LRU (locked) when they are first
used, but they are not faulted in by the mlock call.
This series introduces a new mlock() system call that takes a flags
argument along with the start address and size. This flags argument
gives the caller the ability to request memory be locked in the
traditional way, or to be locked after the page is faulted in. A new
MCL flag is added to mirror the lock on fault behavior from mlock() in
mlockall().
There are two main use cases that this set covers. The first is the
security focussed mlock case. A buffer is needed that cannot be written
to swap. The maximum size is known, but on average the memory used is
significantly less than this maximum. With lock on fault, the buffer
is guaranteed to never be paged out without consuming the maximum size
every time such a buffer is created.
The second use case is focussed on performance. Portions of a large
file are needed and we want to keep the used portions in memory once
accessed. This is the case for large graphical models where the path
through the graph is not known until run time. The entire graph is
unlikely to be used in a given invocation, but once a node has been
used it needs to stay resident for further processing. Given these
constraints we have a number of options. We can potentially waste a
large amount of memory by mlocking the entire region (this can also
cause a significant stall at startup as the entire file is read in).
We can mlock every page as we access them without tracking if the page
is already resident but this introduces large overhead for each access.
The third option is mapping the entire region with PROT_NONE and using
a signal handler for SIGSEGV to mprotect(PROT_READ) and mlock() the
needed page. Doing this page at a time adds a significant performance
penalty. Batching can be used to mitigate this overhead, but in order
to safely avoid trying to mprotect pages outside of the mapping, the
boundaries of each mapping to be used in this way must be tracked and
available to the signal handler. This is precisely what the mm system
in the kernel should already be doing.
For mlock(MLOCK_ONFAULT) the user is charged against RLIMIT_MEMLOCK as
if mlock(MLOCK_LOCKED) or mmap(MAP_LOCKED) was used, so when the VMA is
created not when the pages are faulted in. For mlockall(MCL_ONFAULT)
the user is charged as if MCL_FUTURE was used. This decision was made
to keep the accounting checks out of the page fault path.
To illustrate the benefit of this set I wrote a test program that mmaps
a 5 GB file filled with random data and then makes 15,000,000 accesses
to random addresses in that mapping. The test program was run 20 times
for each setup. Results are reported for two program portions, setup
and execution. The setup phase is calling mmap and optionally mlock on
the entire region. For most experiments this is trivial, but it
highlights the cost of faulting in the entire region. Results are
averages across the 20 runs in milliseconds.
mmap with mlock(MLOCK_LOCKED) on entire range:
Setup avg: 8228.666
Processing avg: 8274.257
mmap with mlock(MLOCK_LOCKED) before each access:
Setup avg: 0.113
Processing avg: 90993.552
mmap with PROT_NONE and signal handler and batch size of 1 page:
With the default value in max_map_count, this gets ENOMEM as I attempt
to change the permissions, after upping the sysctl significantly I get:
Setup avg: 0.058
Processing avg: 69488.073
mmap with PROT_NONE and signal handler and batch size of 8 pages:
Setup avg: 0.068
Processing avg: 38204.116
mmap with PROT_NONE and signal handler and batch size of 16 pages:
Setup avg: 0.044
Processing avg: 29671.180
mmap with mlock(MLOCK_ONFAULT) on entire range:
Setup avg: 0.189
Processing avg: 17904.899
The signal handler in the batch cases faulted in memory in two steps to
avoid having to know the start and end of the faulting mapping. The
first step covers the page that caused the fault as we know that it will
be possible to lock. The second step speculatively tries to mlock and
mprotect the batch size - 1 pages that follow. There may be a clever
way to avoid this without having the program track each mapping to be
covered by this handeler in a globally accessible structure, but I could
not find it. It should be noted that with a large enough batch size
this two step fault handler can still cause the program to crash if it
reaches far beyond the end of the mapping.
These results show that if the developer knows that a majority of the
mapping will be used, it is better to try and fault it in at once,
otherwise mlock(MLOCK_ONFAULT) is significantly faster.
The performance cost of these patches are minimal on the two benchmarks
I have tested (stream and kernbench). The following are the average
values across 20 runs of stream and 10 runs of kernbench after a warmup
run whose results were discarded.
Avg throughput in MB/s from stream using 1000000 element arrays
Test 4.2-rc1 4.2-rc1+lock-on-fault
Copy: 10,566.5 10,421
Scale: 10,685 10,503.5
Add: 12,044.1 11,814.2
Triad: 12,064.8 11,846.3
Kernbench optimal load
4.2-rc1 4.2-rc1+lock-on-fault
Elapsed Time 78.453 78.991
User Time 64.2395 65.2355
System Time 9.7335 9.7085
Context Switches 22211.5 22412.1
Sleeps 14965.3 14956.1
---
Changes from V8:
* Do not expose VM_LOCKONFAULT flag to rmap code
* Rebase on top of userfaultfd code
Changes from V7:
* Do not expose the VM_LOCKONFAULT flag to userspace via proc
* Fix mlock2 self tests
Changes from V6:
* Bump the x86 system call number to avoid collision with userfaultfd
* Fix FOLL_POPULATE and FOLL_MLOCK usage when mmap is called with
MAP_POPULATE
* Add documentation for the proc smaps change
* checkpatch fixes
Changes from V5:
Drop MLOCK_LOCKED flag
* MLOCK_ONFAULT and MCL_ONFAULT are treated as a modifier to other locking
operations, mirroring the relationship between VM_LOCKED and
VM_LOCKONFAULT
* Drop mmap flag and related tests
* Fix clearing of MCL_CURRENT when mlockall is called with MCL_FUTURE,
mlockall behavoir now matches the old behavior WRT to ordering
Changes from V4:
Drop all architectures for new sys call entries except x86[_64] and MIPS
Drop munlock2 and munlockall2
Make VM_LOCKONFAULT a modifier to VM_LOCKED only to simplify book keeping
Adjust tests to match
Changes from V3:
Ensure that pages present when mlock2(MLOCK_ONFAULT) is called are locked
Ensure that VM_LOCKONFAULT is handled in cases that used to only check VM_LOCKED
Add tests for new system calls
Add missing syscall entries, fix NR_syscalls on multiple arch's
Add missing MAP_LOCKONFAULT for tile
Changes from V2:
Added new system calls for mlock, munlock, and munlockall with added
flags arguments for controlling how memory is locked or unlocked.
Eric B Munson (6):
mm: mlock: Refactor mlock, munlock, and munlockall code
mm: mlock: Add new mlock system call
mm: Introduce VM_LOCKONFAULT
mm: mlock: Add mlock flags to enable VM_LOCKONFAULT usage
selftests: vm: Add tests for lock on fault
mips: Add entry for new mlock2 syscall
arch/alpha/include/uapi/asm/mman.h | 3 +
arch/mips/include/uapi/asm/mman.h | 6 +
arch/mips/include/uapi/asm/unistd.h | 15 +-
arch/mips/kernel/scall32-o32.S | 1 +
arch/mips/kernel/scall64-64.S | 1 +
arch/mips/kernel/scall64-n32.S | 1 +
arch/mips/kernel/scall64-o32.S | 1 +
arch/parisc/include/uapi/asm/mman.h | 3 +
arch/powerpc/include/uapi/asm/mman.h | 1 +
arch/sparc/include/uapi/asm/mman.h | 1 +
arch/tile/include/uapi/asm/mman.h | 1 +
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
arch/xtensa/include/uapi/asm/mman.h | 6 +
include/linux/mm.h | 5 +
include/linux/syscalls.h | 2 +
include/uapi/asm-generic/mman-common.h | 5 +
include/uapi/asm-generic/mman.h | 1 +
include/uapi/asm-generic/unistd.h | 4 +-
kernel/fork.c | 3 +-
kernel/sys_ni.c | 1 +
mm/debug.c | 1 +
mm/gup.c | 10 +-
mm/huge_memory.c | 2 +-
mm/hugetlb.c | 4 +-
mm/mlock.c | 86 +++-
mm/mmap.c | 2 +-
tools/testing/selftests/vm/Makefile | 2 +
tools/testing/selftests/vm/mlock2-tests.c | 737 ++++++++++++++++++++++++++++
tools/testing/selftests/vm/on-fault-limit.c | 47 ++
tools/testing/selftests/vm/run_vmtests | 22 +
31 files changed, 938 insertions(+), 38 deletions(-)
create mode 100644 tools/testing/selftests/vm/mlock2-tests.c
create mode 100644 tools/testing/selftests/vm/on-fault-limit.c
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: linux-alpha@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Cc: linux-mm@kvack.org
Cc: linux-arch@vger.kernel.org
Cc: linux-api@vger.kernel.org
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[toc] | [next] | [standalone]
| From | Eric B Munson <emunson@akamai.com> |
|---|---|
| Date | 2015-09-08 16:10 +0200 |
| Subject | [PATCH v9 5/6] selftests: vm: Add tests for lock on fault |
| Message-ID | <q6rKX-6sO-43@gated-at.bofh.it> |
| In reply to | #1220816 |
Test the mmap() flag, and the mlockall() flag. These tests ensure that
pages are not faulted in until they are accessed, that the pages are
unevictable once faulted in, and that VMA splitting and merging works
with the new VM flag. The second test ensures that mlock limits are
respected. Note that the limit test needs to be run a normal user.
Also add tests to use the new mlock2 family of system calls.
Signed-off-by: Eric B Munson <emunson@akamai.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-api@vger.kernel.org
---
tools/testing/selftests/vm/Makefile | 2 +
tools/testing/selftests/vm/mlock2-tests.c | 737 ++++++++++++++++++++++++++++
tools/testing/selftests/vm/on-fault-limit.c | 47 ++
tools/testing/selftests/vm/run_vmtests | 22 +
4 files changed, 808 insertions(+)
create mode 100644 tools/testing/selftests/vm/mlock2-tests.c
create mode 100644 tools/testing/selftests/vm/on-fault-limit.c
diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
index 0d68547..2da6608 100644
--- a/tools/testing/selftests/vm/Makefile
+++ b/tools/testing/selftests/vm/Makefile
@@ -6,6 +6,8 @@ BINARIES += hugepage-mmap
BINARIES += hugepage-shm
BINARIES += hugetlbfstest
BINARIES += map_hugetlb
+BINARIES += mlock2-tests
+BINARIES += on-fault-limit
BINARIES += thuge-gen
BINARIES += transhuge-stress
BINARIES += userfaultfd
diff --git a/tools/testing/selftests/vm/mlock2-tests.c b/tools/testing/selftests/vm/mlock2-tests.c
new file mode 100644
index 0000000..909802e
--- /dev/null
+++ b/tools/testing/selftests/vm/mlock2-tests.c
@@ -0,0 +1,737 @@
+#include <sys/mman.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <syscall.h>
+#include <errno.h>
+#include <stdbool.h>
+
+#ifndef MLOCK_ONFAULT
+#define MLOCK_ONFAULT 1
+#endif
+
+#ifndef MCL_ONFAULT
+#define MCL_ONFAULT (MCL_FUTURE << 1)
+#endif
+
+static int mlock2_(void *start, size_t len, int flags)
+{
+#ifdef __NR_mlock2
+ return syscall(__NR_mlock2, start, len, flags);
+#else
+ errno = ENOSYS;
+ return -1;
+#endif
+}
+
+struct vm_boundaries {
+ unsigned long start;
+ unsigned long end;
+};
+
+static int get_vm_area(unsigned long addr, struct vm_boundaries *area)
+{
+ FILE *file;
+ int ret = 1;
+ char line[1024] = {0};
+ char *end_addr;
+ char *stop;
+ unsigned long start;
+ unsigned long end;
+
+ if (!area)
+ return ret;
+
+ file = fopen("/proc/self/maps", "r");
+ if (!file) {
+ perror("fopen");
+ return ret;
+ }
+
+ memset(area, 0, sizeof(struct vm_boundaries));
+
+ while(fgets(line, 1024, file)) {
+ end_addr = strchr(line, '-');
+ if (!end_addr) {
+ printf("cannot parse /proc/self/maps\n");
+ goto out;
+ }
+ *end_addr = '\0';
+ end_addr++;
+ stop = strchr(end_addr, ' ');
+ if (!stop) {
+ printf("cannot parse /proc/self/maps\n");
+ goto out;
+ }
+ stop = '\0';
+
+ sscanf(line, "%lx", &start);
+ sscanf(end_addr, "%lx", &end);
+
+ if (start <= addr && end > addr) {
+ area->start = start;
+ area->end = end;
+ ret = 0;
+ goto out;
+ }
+ }
+out:
+ fclose(file);
+ return ret;
+}
+
+static uint64_t get_pageflags(unsigned long addr)
+{
+ FILE *file;
+ uint64_t pfn;
+ unsigned long offset;
+
+ file = fopen("/proc/self/pagemap", "r");
+ if (!file) {
+ perror("fopen pagemap");
+ _exit(1);
+ }
+
+ offset = addr / getpagesize() * sizeof(pfn);
+
+ if (fseek(file, offset, SEEK_SET)) {
+ perror("fseek pagemap");
+ _exit(1);
+ }
+
+ if (fread(&pfn, sizeof(pfn), 1, file) != 1) {
+ perror("fread pagemap");
+ _exit(1);
+ }
+
+ fclose(file);
+ return pfn;
+}
+
+static uint64_t get_kpageflags(unsigned long pfn)
+{
+ uint64_t flags;
+ FILE *file;
+
+ file = fopen("/proc/kpageflags", "r");
+ if (!file) {
+ perror("fopen kpageflags");
+ _exit(1);
+ }
+
+ if (fseek(file, pfn * sizeof(flags), SEEK_SET)) {
+ perror("fseek kpageflags");
+ _exit(1);
+ }
+
+ if (fread(&flags, sizeof(flags), 1, file) != 1) {
+ perror("fread kpageflags");
+ _exit(1);
+ }
+
+ fclose(file);
+ return flags;
+}
+
+static FILE *seek_to_smaps_entry(unsigned long addr)
+{
+ FILE *file;
+ char *line = NULL;
+ size_t size = 0;
+ unsigned long start, end;
+ char perms[5];
+ unsigned long offset;
+ char dev[32];
+ unsigned long inode;
+ char path[BUFSIZ];
+
+ file = fopen("/proc/self/smaps", "r");
+ if (!file) {
+ perror("fopen smaps");
+ _exit(1);
+ }
+
+ while (getline(&line, &size, file) > 0) {
+ if (sscanf(line, "%lx-%lx %s %lx %s %lu %s\n",
+ &start, &end, perms, &offset, dev, &inode, path) < 6)
+ goto next;
+
+ if (start <= addr && addr < end)
+ goto out;
+
+next:
+ free(line);
+ line = NULL;
+ size = 0;
+ }
+
+ fclose(file);
+ file = NULL;
+
+out:
+ free(line);
+ return file;
+}
+
+#define VMFLAGS "VmFlags:"
+
+static bool is_vmflag_set(unsigned long addr, const char *vmflag)
+{
+ char *line = NULL;
+ char *flags;
+ size_t size = 0;
+ bool ret = false;
+ FILE *smaps;
+
+ smaps = seek_to_smaps_entry(addr);
+ if (!smaps) {
+ printf("Unable to parse /proc/self/smaps\n");
+ goto out;
+ }
+
+ while (getline(&line, &size, smaps) > 0) {
+ if (!strstr(line, VMFLAGS)) {
+ free(line);
+ line = NULL;
+ size = 0;
+ continue;
+ }
+
+ flags = line + strlen(VMFLAGS);
+ ret = (strstr(flags, vmflag) != NULL);
+ goto out;
+ }
+
+out:
+ free(line);
+ fclose(smaps);
+ return ret;
+}
+
+#define SIZE "Size:"
+#define RSS "Rss:"
+#define LOCKED "lo"
+
+static bool is_vma_lock_on_fault(unsigned long addr)
+{
+ bool ret = false;
+ bool locked;
+ FILE *smaps = NULL;
+ unsigned long vma_size, vma_rss;
+ char *line = NULL;
+ char *value;
+ size_t size = 0;
+
+ locked = is_vmflag_set(addr, LOCKED);
+ if (!locked)
+ goto out;
+
+ smaps = seek_to_smaps_entry(addr);
+ if (!smaps) {
+ printf("Unable to parse /proc/self/smaps\n");
+ goto out;
+ }
+
+ while (getline(&line, &size, smaps) > 0) {
+ if (!strstr(line, SIZE)) {
+ free(line);
+ line = NULL;
+ size = 0;
+ continue;
+ }
+
+ value = line + strlen(SIZE);
+ if (sscanf(value, "%lu kB", &vma_size) < 1) {
+ printf("Unable to parse smaps entry for Size\n");
+ goto out;
+ }
+ break;
+ }
+
+ while (getline(&line, &size, smaps) > 0) {
+ if (!strstr(line, RSS)) {
+ free(line);
+ line = NULL;
+ size = 0;
+ continue;
+ }
+
+ value = line + strlen(RSS);
+ if (sscanf(value, "%lu kB", &vma_rss) < 1) {
+ printf("Unable to parse smaps entry for Rss\n");
+ goto out;
+ }
+ break;
+ }
+
+ ret = locked && (vma_rss < vma_size);
+out:
+ free(line);
+ if (smaps)
+ fclose(smaps);
+ return ret;
+}
+
+#define PRESENT_BIT 0x8000000000000000
+#define PFN_MASK 0x007FFFFFFFFFFFFF
+#define UNEVICTABLE_BIT (1UL << 18)
+
+static int lock_check(char *map)
+{
+ unsigned long page_size = getpagesize();
+ uint64_t page1_flags, page2_flags;
+
+ page1_flags = get_pageflags((unsigned long)map);
+ page2_flags = get_pageflags((unsigned long)map + page_size);
+
+ /* Both pages should be present */
+ if (((page1_flags & PRESENT_BIT) == 0) ||
+ ((page2_flags & PRESENT_BIT) == 0)) {
+ printf("Failed to make both pages present\n");
+ return 1;
+ }
+
+ page1_flags = get_kpageflags(page1_flags & PFN_MASK);
+ page2_flags = get_kpageflags(page2_flags & PFN_MASK);
+
+ /* Both pages should be unevictable */
+ if (((page1_flags & UNEVICTABLE_BIT) == 0) ||
+ ((page2_flags & UNEVICTABLE_BIT) == 0)) {
+ printf("Failed to make both pages unevictable\n");
+ return 1;
+ }
+
+ if (!is_vmflag_set((unsigned long)map, LOCKED)) {
+ printf("VMA flag %s is missing on page 1\n", LOCKED);
+ return 1;
+ }
+
+ if (!is_vmflag_set((unsigned long)map + page_size, LOCKED)) {
+ printf("VMA flag %s is missing on page 2\n", LOCKED);
+ return 1;
+ }
+
+ return 0;
+}
+
+static int unlock_lock_check(char *map)
+{
+ unsigned long page_size = getpagesize();
+ uint64_t page1_flags, page2_flags;
+
+ page1_flags = get_pageflags((unsigned long)map);
+ page2_flags = get_pageflags((unsigned long)map + page_size);
+ page1_flags = get_kpageflags(page1_flags & PFN_MASK);
+ page2_flags = get_kpageflags(page2_flags & PFN_MASK);
+
+ if ((page1_flags & UNEVICTABLE_BIT) || (page2_flags & UNEVICTABLE_BIT)) {
+ printf("A page is still marked unevictable after unlock\n");
+ return 1;
+ }
+
+ if (is_vmflag_set((unsigned long)map, LOCKED)) {
+ printf("VMA flag %s is present on page 1 after unlock\n", LOCKED);
+ return 1;
+ }
+
+ if (is_vmflag_set((unsigned long)map + page_size, LOCKED)) {
+ printf("VMA flag %s is present on page 2 after unlock\n", LOCKED);
+ return 1;
+ }
+
+ return 0;
+}
+
+static int test_mlock_lock()
+{
+ char *map;
+ int ret = 1;
+ unsigned long page_size = getpagesize();
+
+ map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+ if (map == MAP_FAILED) {
+ perror("test_mlock_locked mmap");
+ goto out;
+ }
+
+ if (mlock2_(map, 2 * page_size, 0)) {
+ if (errno == ENOSYS) {
+ printf("Cannot call new mlock family, skipping test\n");
+ _exit(0);
+ }
+ perror("mlock2(0)");
+ goto unmap;
+ }
+
+ if (lock_check(map))
+ goto unmap;
+
+ /* Now unlock and recheck attributes */
+ if (munlock(map, 2 * page_size)) {
+ perror("munlock()");
+ goto unmap;
+ }
+
+ ret = unlock_lock_check(map);
+
+unmap:
+ munmap(map, 2 * page_size);
+out:
+ return ret;
+}
+
+static int onfault_check(char *map)
+{
+ unsigned long page_size = getpagesize();
+ uint64_t page1_flags, page2_flags;
+
+ page1_flags = get_pageflags((unsigned long)map);
+ page2_flags = get_pageflags((unsigned long)map + page_size);
+
+ /* Neither page should be present */
+ if ((page1_flags & PRESENT_BIT) || (page2_flags & PRESENT_BIT)) {
+ printf("Pages were made present by MLOCK_ONFAULT\n");
+ return 1;
+ }
+
+ *map = 'a';
+ page1_flags = get_pageflags((unsigned long)map);
+ page2_flags = get_pageflags((unsigned long)map + page_size);
+
+ /* Only page 1 should be present */
+ if ((page1_flags & PRESENT_BIT) == 0) {
+ printf("Page 1 is not present after fault\n");
+ return 1;
+ } else if (page2_flags & PRESENT_BIT) {
+ printf("Page 2 was made present\n");
+ return 1;
+ }
+
+ page1_flags = get_kpageflags(page1_flags & PFN_MASK);
+
+ /* Page 1 should be unevictable */
+ if ((page1_flags & UNEVICTABLE_BIT) == 0) {
+ printf("Failed to make faulted page unevictable\n");
+ return 1;
+ }
+
+ if (!is_vma_lock_on_fault((unsigned long)map)) {
+ printf("VMA is not marked for lock on fault\n");
+ return 1;
+ }
+
+ if (!is_vma_lock_on_fault((unsigned long)map + page_size)) {
+ printf("VMA is not marked for lock on fault\n");
+ return 1;
+ }
+
+ return 0;
+}
+
+static int unlock_onfault_check(char *map)
+{
+ unsigned long page_size = getpagesize();
+ uint64_t page1_flags;
+
+ page1_flags = get_pageflags((unsigned long)map);
+ page1_flags = get_kpageflags(page1_flags & PFN_MASK);
+
+ if (page1_flags & UNEVICTABLE_BIT) {
+ printf("Page 1 is still marked unevictable after unlock\n");
+ return 1;
+ }
+
+ if (is_vma_lock_on_fault((unsigned long)map) ||
+ is_vma_lock_on_fault((unsigned long)map + page_size)) {
+ printf("VMA is still lock on fault after unlock\n");
+ return 1;
+ }
+
+ return 0;
+}
+
+static int test_mlock_onfault()
+{
+ char *map;
+ int ret = 1;
+ unsigned long page_size = getpagesize();
+
+ map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+ if (map == MAP_FAILED) {
+ perror("test_mlock_locked mmap");
+ goto out;
+ }
+
+ if (mlock2_(map, 2 * page_size, MLOCK_ONFAULT)) {
+ if (errno == ENOSYS) {
+ printf("Cannot call new mlock family, skipping test\n");
+ _exit(0);
+ }
+ perror("mlock2(MLOCK_ONFAULT)");
+ goto unmap;
+ }
+
+ if (onfault_check(map))
+ goto unmap;
+
+ /* Now unlock and recheck attributes */
+ if (munlock(map, 2 * page_size)) {
+ if (errno == ENOSYS) {
+ printf("Cannot call new mlock family, skipping test\n");
+ _exit(0);
+ }
+ perror("munlock()");
+ goto unmap;
+ }
+
+ ret = unlock_onfault_check(map);
+unmap:
+ munmap(map, 2 * page_size);
+out:
+ return ret;
+}
+
+static int test_lock_onfault_of_present()
+{
+ char *map;
+ int ret = 1;
+ unsigned long page_size = getpagesize();
+ uint64_t page1_flags, page2_flags;
+
+ map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+ if (map == MAP_FAILED) {
+ perror("test_mlock_locked mmap");
+ goto out;
+ }
+
+ *map = 'a';
+
+ if (mlock2_(map, 2 * page_size, MLOCK_ONFAULT)) {
+ if (errno == ENOSYS) {
+ printf("Cannot call new mlock family, skipping test\n");
+ _exit(0);
+ }
+ perror("mlock2(MLOCK_ONFAULT)");
+ goto unmap;
+ }
+
+ page1_flags = get_pageflags((unsigned long)map);
+ page2_flags = get_pageflags((unsigned long)map + page_size);
+ page1_flags = get_kpageflags(page1_flags & PFN_MASK);
+ page2_flags = get_kpageflags(page2_flags & PFN_MASK);
+
+ /* Page 1 should be unevictable */
+ if ((page1_flags & UNEVICTABLE_BIT) == 0) {
+ printf("Failed to make present page unevictable\n");
+ goto unmap;
+ }
+
+ if (!is_vma_lock_on_fault((unsigned long)map) ||
+ !is_vma_lock_on_fault((unsigned long)map + page_size)) {
+ printf("VMA with present pages is not marked lock on fault\n");
+ goto unmap;
+ }
+ ret = 0;
+unmap:
+ munmap(map, 2 * page_size);
+out:
+ return ret;
+}
+
+static int test_munlockall()
+{
+ char *map;
+ int ret = 1;
+ unsigned long page_size = getpagesize();
+
+ map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+
+ if (map == MAP_FAILED) {
+ perror("test_munlockall mmap");
+ goto out;
+ }
+
+ if (mlockall(MCL_CURRENT)) {
+ perror("mlockall(MCL_CURRENT)");
+ goto out;
+ }
+
+ if (lock_check(map))
+ goto unmap;
+
+ if (munlockall()) {
+ perror("munlockall()");
+ goto unmap;
+ }
+
+ if (unlock_lock_check(map))
+ goto unmap;
+
+ munmap(map, 2 * page_size);
+
+ map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+
+ if (map == MAP_FAILED) {
+ perror("test_munlockall second mmap");
+ goto out;
+ }
+
+ if (mlockall(MCL_CURRENT | MCL_ONFAULT)) {
+ perror("mlockall(MCL_CURRENT | MCL_ONFAULT)");
+ goto unmap;
+ }
+
+ if (onfault_check(map))
+ goto unmap;
+
+ if (munlockall()) {
+ perror("munlockall()");
+ goto unmap;
+ }
+
+ if (unlock_onfault_check(map))
+ goto unmap;
+
+ if (mlockall(MCL_CURRENT | MCL_FUTURE)) {
+ perror("mlockall(MCL_CURRENT | MCL_FUTURE)");
+ goto out;
+ }
+
+ if (lock_check(map))
+ goto unmap;
+
+ if (munlockall()) {
+ perror("munlockall()");
+ goto unmap;
+ }
+
+ ret = unlock_lock_check(map);
+
+unmap:
+ munmap(map, 2 * page_size);
+out:
+ munlockall();
+ return ret;
+}
+
+static int test_vma_management(bool call_mlock)
+{
+ int ret = 1;
+ void *map;
+ unsigned long page_size = getpagesize();
+ struct vm_boundaries page1;
+ struct vm_boundaries page2;
+ struct vm_boundaries page3;
+
+ map = mmap(NULL, 3 * page_size, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+ if (map == MAP_FAILED) {
+ perror("mmap()");
+ return ret;
+ }
+
+ if (call_mlock && mlock2_(map, 3 * page_size, MLOCK_ONFAULT)) {
+ if (errno == ENOSYS) {
+ printf("Cannot call new mlock family, skipping test\n");
+ _exit(0);
+ }
+ perror("mlock(ONFAULT)\n");
+ goto out;
+ }
+
+ if (get_vm_area((unsigned long)map, &page1) ||
+ get_vm_area((unsigned long)map + page_size, &page2) ||
+ get_vm_area((unsigned long)map + page_size * 2, &page3)) {
+ printf("couldn't find mapping in /proc/self/maps\n");
+ goto out;
+ }
+
+ /*
+ * Before we unlock a portion, we need to that all three pages are in
+ * the same VMA. If they are not we abort this test (Note that this is
+ * not a failure)
+ */
+ if (page1.start != page2.start || page2.start != page3.start) {
+ printf("VMAs are not merged to start, aborting test\n");
+ ret = 0;
+ goto out;
+ }
+
+ if (munlock(map + page_size, page_size)) {
+ perror("munlock()");
+ goto out;
+ }
+
+ if (get_vm_area((unsigned long)map, &page1) ||
+ get_vm_area((unsigned long)map + page_size, &page2) ||
+ get_vm_area((unsigned long)map + page_size * 2, &page3)) {
+ printf("couldn't find mapping in /proc/self/maps\n");
+ goto out;
+ }
+
+ /* All three VMAs should be different */
+ if (page1.start == page2.start || page2.start == page3.start) {
+ printf("failed to split VMA for munlock\n");
+ goto out;
+ }
+
+ /* Now unlock the first and third page and check the VMAs again */
+ if (munlock(map, page_size * 3)) {
+ perror("munlock()");
+ goto out;
+ }
+
+ if (get_vm_area((unsigned long)map, &page1) ||
+ get_vm_area((unsigned long)map + page_size, &page2) ||
+ get_vm_area((unsigned long)map + page_size * 2, &page3)) {
+ printf("couldn't find mapping in /proc/self/maps\n");
+ goto out;
+ }
+
+ /* Now all three VMAs should be the same */
+ if (page1.start != page2.start || page2.start != page3.start) {
+ printf("failed to merge VMAs after munlock\n");
+ goto out;
+ }
+
+ ret = 0;
+out:
+ munmap(map, 3 * page_size);
+ return ret;
+}
+
+static int test_mlockall(int (test_function)(bool call_mlock))
+{
+ int ret = 1;
+
+ if (mlockall(MCL_CURRENT | MCL_ONFAULT | MCL_FUTURE)) {
+ perror("mlockall");
+ return ret;
+ }
+
+ ret = test_function(false);
+ munlockall();
+ return ret;
+}
+
+int main(int argc, char **argv)
+{
+ int ret = 0;
+ ret += test_mlock_lock();
+ ret += test_mlock_onfault();
+ ret += test_munlockall();
+ ret += test_lock_onfault_of_present();
+ ret += test_vma_management(true);
+ ret += test_mlockall(test_vma_management);
+ return ret;
+}
+
diff --git a/tools/testing/selftests/vm/on-fault-limit.c b/tools/testing/selftests/vm/on-fault-limit.c
new file mode 100644
index 0000000..245accc
--- /dev/null
+++ b/tools/testing/selftests/vm/on-fault-limit.c
@@ -0,0 +1,47 @@
+#include <sys/mman.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+
+#ifndef MCL_ONFAULT
+#define MCL_ONFAULT (MCL_FUTURE << 1)
+#endif
+
+static int test_limit(void)
+{
+ int ret = 1;
+ struct rlimit lims;
+ void *map;
+
+ if (getrlimit(RLIMIT_MEMLOCK, &lims)) {
+ perror("getrlimit");
+ return ret;
+ }
+
+ if (mlockall(MCL_CURRENT | MCL_ONFAULT | MCL_FUTURE)) {
+ perror("mlockall");
+ return ret;
+ }
+
+ map = mmap(NULL, 2 * lims.rlim_max, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, 0, 0);
+ if (map != MAP_FAILED)
+ printf("mmap should have failed, but didn't\n");
+ else {
+ ret = 0;
+ munmap(map, 2 * lims.rlim_max);
+ }
+
+ munlockall();
+ return ret;
+}
+
+int main(int argc, char **argv)
+{
+ int ret = 0;
+
+ ret += test_limit();
+ return ret;
+}
diff --git a/tools/testing/selftests/vm/run_vmtests b/tools/testing/selftests/vm/run_vmtests
index 831adeb..231174a 100755
--- a/tools/testing/selftests/vm/run_vmtests
+++ b/tools/testing/selftests/vm/run_vmtests
@@ -113,4 +113,26 @@ else
echo "[PASS]"
fi
+echo "--------------------"
+echo "running on-fault-limit"
+echo "--------------------"
+sudo -u nobody ./on-fault-limit
+if [ $? -ne 0 ]; then
+ echo "[FAIL]"
+ exitcode=1
+else
+ echo "[PASS]"
+fi
+
+echo "--------------------"
+echo "running mlock2-tests"
+echo "--------------------"
+./mlock2-tests
+if [ $? -ne 0 ]; then
+ echo "[FAIL]"
+ exitcode=1
+else
+ echo "[PASS]"
+fi
+
exit $exitcode
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[toc] | [prev] | [standalone]
Back to top | Article view | linux.kernel
csiph-web