| Message ID | 20180801233636.29354-1-dima@arista.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/selftest: Add MAP_POPULATE test | expand |
Hi Dmitry, Thanks for the test. A few comments below. On 08/01/2018 05:36 PM, Dmitry Safonov wrote: > As many other projects, we use some shmalloc allocator. > At some point we need to make a part of allocated pages back private to > process. And it should be populated straight away. > Check that (MAP_PRIVATE | MAP_POPULATE) actually copies the private page. It is not clear from this commit log what this test is doing? It would be helpful to rephrase. "MAP_POPULATE | MAP_PRIVATE memory maps should COW VMA pages. This test is for verifying that it does" something along the lines?? > > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Dmitry Safonov <0x7f454c46@gmail.com> > Cc: Hua Zhong <hzhong@arista.com> > Cc: Shuah Khan <shuah@kernel.org> > Cc: Stuart Ritchie <sritchie@arista.com> > Cc: linux-kselftest@vger.kernel.org > Signed-off-by: Dmitry Safonov <dima@arista.com> > --- > tools/testing/selftests/vm/.gitignore | 1 + > tools/testing/selftests/vm/Makefile | 1 + > tools/testing/selftests/vm/map_populate.c | 113 ++++++++++++++++++++++++++++++ > tools/testing/selftests/vm/run_vmtests | 11 +++ > 4 files changed, 126 insertions(+) > create mode 100644 tools/testing/selftests/vm/map_populate.c > > diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore > index 342c7bc9dc8c..af5ff83f6d7f 100644 > --- a/tools/testing/selftests/vm/.gitignore > +++ b/tools/testing/selftests/vm/.gitignore > @@ -1,6 +1,7 @@ > hugepage-mmap > hugepage-shm > map_hugetlb > +map_populate > thuge-gen > compaction_test > mlock2-tests > diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile > index fdefa2295ddc..9881876d2aa0 100644 > --- a/tools/testing/selftests/vm/Makefile > +++ b/tools/testing/selftests/vm/Makefile > @@ -12,6 +12,7 @@ TEST_GEN_FILES += gup_benchmark > TEST_GEN_FILES += hugepage-mmap > TEST_GEN_FILES += hugepage-shm > TEST_GEN_FILES += map_hugetlb > +TEST_GEN_FILES += map_populate > TEST_GEN_FILES += mlock-random-test > TEST_GEN_FILES += mlock2-tests > TEST_GEN_FILES += on-fault-limit > diff --git a/tools/testing/selftests/vm/map_populate.c b/tools/testing/selftests/vm/map_populate.c > new file mode 100644 > index 000000000000..df3eacc8eecb > --- /dev/null > +++ b/tools/testing/selftests/vm/map_populate.c > @@ -0,0 +1,113 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (c) 2018 Dmitry Safonov, Arista Networks > + * > + * MAP_POPULATE | MAP_PRIVATE should COW VMA pages. > + */ > + > +#define _GNU_SOURCE > +#include <errno.h> > +#include <fcntl.h> > +#include <sys/mman.h> > +#include <sys/socket.h> > +#include <sys/types.h> > +#include <sys/wait.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > +#include <unistd.h> > + > +#ifndef MMAP_SZ > +#define MMAP_SZ 4096 > +#endif > + > +#define BUG_ON(condition, description) \ > + do { \ > + if (condition) { \ > + fprintf(stderr, "[FAIL]\t%s:%d\t%s:%s\n", __func__, \ > + __LINE__, (description), strerror(errno)); \ > + exit(1); \ > + } \ > + } while (0) > + > +static int parent_f(int sock, unsigned long *smap, int child) > +{ > + int status, ret; > + > + ret = read(sock, &status, sizeof(int)); > + BUG_ON(ret <= 0, "read(sock)"); > + > + *smap = 0x22222BAD; > + ret = msync(smap, MMAP_SZ, MS_SYNC); > + BUG_ON(ret, "msync()"); > + > + ret = write(sock, &status, sizeof(int)); > + BUG_ON(ret <= 0, "write(sock)"); > + > + waitpid(child, &status, 0); > + BUG_ON(!WIFEXITED(status), "child hasn't suicide by own will"); What does this mean? Could you rephrase this please? > + > + return WEXITSTATUS(status); > +} > + > +static int child_f(int sock, unsigned long *smap, int fd) > +{ > + int ret, buf = 0; > + > + smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE, > + MAP_PRIVATE | MAP_POPULATE, fd, 0); > + BUG_ON(smap == MAP_FAILED, "mmap()"); > + > + BUG_ON(*smap != 0xdeadbabe, "MAP_PRIVATE | MAP_POPULATE changed file"); What is expected here? What is expected? > + > + ret = write(sock, &buf, sizeof(int)); > + BUG_ON(ret <= 0, "write(sock)"); > + > + ret = read(sock, &buf, sizeof(int)); > + BUG_ON(ret <= 0, "read(sock)"); > + > + BUG_ON(*smap == 0x22222BAD, "MAP_POPULATE didn't COW private page"); > + BUG_ON(*smap != 0xdeadbabe, "mapping was corrupted"); > + > + return 0; > +} > + > +int main(int argc, char **argv) > +{ > + int sock[2], child, ret; > + FILE *ftmp; > + unsigned long *smap; > + > + ftmp = tmpfile(); > + BUG_ON(ftmp == 0, "tmpfile()"); > + > + ret = ftruncate(fileno(ftmp), MMAP_SZ); > + BUG_ON(ret, "ftruncate()"); > + > + smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE, > + MAP_SHARED, fileno(ftmp), 0); > + BUG_ON(smap == MAP_FAILED, "mmap()"); > + > + *smap = 0xdeadbabe; > + /* Probably unnecessary, but let it be. */ > + ret = msync(smap, MMAP_SZ, MS_SYNC); > + BUG_ON(ret, "msync()"); > + > + ret = socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sock); > + BUG_ON(ret, "socketpair()"); > + > + child = fork(); > + BUG_ON(child == -1, "fork()"); > + > + if (child) { > + ret = close(sock[0]); > + BUG_ON(ret, "close()"); > + > + return parent_f(sock[1], smap, child); > + } > + > + ret = close(sock[1]); > + BUG_ON(ret, "close()"); > + > + return child_f(sock[0], smap, fileno(ftmp)); > +} > diff --git a/tools/testing/selftests/vm/run_vmtests b/tools/testing/selftests/vm/run_vmtests > index 88cbe5575f0c..584a91ae4a8f 100755 > --- a/tools/testing/selftests/vm/run_vmtests > +++ b/tools/testing/selftests/vm/run_vmtests > @@ -168,6 +168,17 @@ else > fi > > echo "--------------------" > +echo "running map_populate" > +echo "--------------------" > +./map_populate > +if [ $? -ne 0 ]; then > + echo "[FAIL]" > + exitcode=1 > +else > + echo "[PASS]" > +fi > + > +echo "--------------------" > echo "running mlock2-tests" > echo "--------------------" > ./mlock2-tests > thanks, -- Shuah -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2 Aug 2018 00:36:36 +0100 Dmitry Safonov <dima@arista.com> wrote: > As many other projects, we use some shmalloc allocator. > At some point we need to make a part of allocated pages back private to > process. And it should be populated straight away. > Check that (MAP_PRIVATE | MAP_POPULATE) actually copies the private page. > > ... > > --- /dev/null > +++ b/tools/testing/selftests/vm/map_populate.c > > ... > > +#define BUG_ON(condition, description) \ > + do { \ > + if (condition) { \ > + fprintf(stderr, "[FAIL]\t%s:%d\t%s:%s\n", __func__, \ > + __LINE__, (description), strerror(errno)); \ > + exit(1); \ > + } \ > + } while (0) This is userspace. Why not use assert()? > > ... > > +int main(int argc, char **argv) > +{ > + int sock[2], child, ret; > + FILE *ftmp; > + unsigned long *smap; > + > + ftmp = tmpfile(); Seems odd to putz around with stdio when you just want the fd. mkstemp(), maybe? > + BUG_ON(ftmp == 0, "tmpfile()"); > + > + ret = ftruncate(fileno(ftmp), MMAP_SZ); > + BUG_ON(ret, "ftruncate()"); > + > + smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE, > + MAP_SHARED, fileno(ftmp), 0); > + BUG_ON(smap == MAP_FAILED, "mmap()"); > + > + *smap = 0xdeadbabe; > + /* Probably unnecessary, but let it be. */ > + ret = msync(smap, MMAP_SZ, MS_SYNC); > + BUG_ON(ret, "msync()"); > + > + ret = socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sock); > + BUG_ON(ret, "socketpair()"); > + > + child = fork(); > + BUG_ON(child == -1, "fork()"); > + > + if (child) { > + ret = close(sock[0]); > + BUG_ON(ret, "close()"); > + > + return parent_f(sock[1], smap, child); > + } > + > + ret = close(sock[1]); > + BUG_ON(ret, "close()"); > + > + return child_f(sock[0], smap, fileno(ftmp)); > +} > > ... > -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 2018-08-01 at 18:02 -0600, Shuah Khan wrote: > Hi Dmitry, Hi Shuah, Thanks for the review, > > Thanks for the test. A few comments below. > > On 08/01/2018 05:36 PM, Dmitry Safonov wrote: > > As many other projects, we use some shmalloc allocator. > > At some point we need to make a part of allocated pages back > > private to > > process. And it should be populated straight away. > > Check that (MAP_PRIVATE | MAP_POPULATE) actually copies the private > > page. > > It is not clear from this commit log what this test is doing? It > would > be helpful to rephrase. > > "MAP_POPULATE | MAP_PRIVATE memory maps should COW VMA pages. This > test is > for verifying that it does" something along the lines?? Uhm, no. COW VMA is just MAP_PRIVATE. IOW, if you do mmap(MAP_PRIVATE), you need to actually "touch" (call write() on) the pages to get a copy. Which might be not handy if one has hundreds of pages in a VMA. But mmap(MAP_PRIVATE | MAP_POPULATE) should return mapping with already pre-copied pages, not the COW. > > > > > Cc: Andrew Morton <akpm@linux-foundation.org> > > Cc: Dmitry Safonov <0x7f454c46@gmail.com> > > Cc: Hua Zhong <hzhong@arista.com> > > Cc: Shuah Khan <shuah@kernel.org> > > Cc: Stuart Ritchie <sritchie@arista.com> > > Cc: linux-kselftest@vger.kernel.org > > Signed-off-by: Dmitry Safonov <dima@arista.com> > > --- > > tools/testing/selftests/vm/.gitignore | 1 + > > tools/testing/selftests/vm/Makefile | 1 + > > tools/testing/selftests/vm/map_populate.c | 113 > > ++++++++++++++++++++++++++++++ > > tools/testing/selftests/vm/run_vmtests | 11 +++ > > 4 files changed, 126 insertions(+) > > create mode 100644 tools/testing/selftests/vm/map_populate.c > > > > diff --git a/tools/testing/selftests/vm/.gitignore > > b/tools/testing/selftests/vm/.gitignore > > index 342c7bc9dc8c..af5ff83f6d7f 100644 > > --- a/tools/testing/selftests/vm/.gitignore > > +++ b/tools/testing/selftests/vm/.gitignore > > @@ -1,6 +1,7 @@ > > hugepage-mmap > > hugepage-shm > > map_hugetlb > > +map_populate > > thuge-gen > > compaction_test > > mlock2-tests > > diff --git a/tools/testing/selftests/vm/Makefile > > b/tools/testing/selftests/vm/Makefile > > index fdefa2295ddc..9881876d2aa0 100644 > > --- a/tools/testing/selftests/vm/Makefile > > +++ b/tools/testing/selftests/vm/Makefile > > @@ -12,6 +12,7 @@ TEST_GEN_FILES += gup_benchmark > > TEST_GEN_FILES += hugepage-mmap > > TEST_GEN_FILES += hugepage-shm > > TEST_GEN_FILES += map_hugetlb > > +TEST_GEN_FILES += map_populate > > TEST_GEN_FILES += mlock-random-test > > TEST_GEN_FILES += mlock2-tests > > TEST_GEN_FILES += on-fault-limit > > diff --git a/tools/testing/selftests/vm/map_populate.c > > b/tools/testing/selftests/vm/map_populate.c > > new file mode 100644 > > index 000000000000..df3eacc8eecb > > --- /dev/null > > +++ b/tools/testing/selftests/vm/map_populate.c > > @@ -0,0 +1,113 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * Copyright (c) 2018 Dmitry Safonov, Arista Networks > > + * > > + * MAP_POPULATE | MAP_PRIVATE should COW VMA pages. > > + */ > > + > > +#define _GNU_SOURCE > > +#include <errno.h> > > +#include <fcntl.h> > > +#include <sys/mman.h> > > +#include <sys/socket.h> > > +#include <sys/types.h> > > +#include <sys/wait.h> > > +#include <stdio.h> > > +#include <stdlib.h> > > +#include <string.h> > > +#include <unistd.h> > > + > > +#ifndef MMAP_SZ > > +#define MMAP_SZ 4096 > > +#endif > > + > > +#define BUG_ON(condition, description) > > \ > > + do { > > \ > > + if (condition) { > > \ > > + fprintf(stderr, "[FAIL]\t%s:%d\t%s:%s\n", > > __func__, \ > > + __LINE__, (description), > > strerror(errno)); \ > > + exit(1); > > \ > > + } > > \ > > + } while (0) > > + > > +static int parent_f(int sock, unsigned long *smap, int child) > > +{ > > + int status, ret; > > + > > + ret = read(sock, &status, sizeof(int)); > > + BUG_ON(ret <= 0, "read(sock)"); > > + > > + *smap = 0x22222BAD; > > + ret = msync(smap, MMAP_SZ, MS_SYNC); > > + BUG_ON(ret, "msync()"); > > + > > + ret = write(sock, &status, sizeof(int)); > > + BUG_ON(ret <= 0, "write(sock)"); > > + > > + waitpid(child, &status, 0); > > + BUG_ON(!WIFEXITED(status), "child hasn't suicide by own > > will"); > > What does this mean? Could you rephrase this please? Sure, I didn't want to write "child hasn't exited" because it sounds like it still alive.. I can change it to "child in unexpected state" if that sounds any better? Or I can check WIFSIGNALED(), WIFSIGNALED(), WIFSTOPPED() too and write what happened to the child, but it will needlessly blow the code. > > > + > > + return WEXITSTATUS(status); > > +} > > + > > +static int child_f(int sock, unsigned long *smap, int fd) > > +{ > > + int ret, buf = 0; > > + > > + smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE, > > + MAP_PRIVATE | MAP_POPULATE, fd, 0); > > + BUG_ON(smap == MAP_FAILED, "mmap()"); > > + > > + BUG_ON(*smap != 0xdeadbabe, "MAP_PRIVATE | MAP_POPULATE > > changed file"); > > What is expected here? What is expected? It's expected that the value in file is the same as before remapping it MAP_PRIVATE (same as parent set initially). > > > + > > + ret = write(sock, &buf, sizeof(int)); > > + BUG_ON(ret <= 0, "write(sock)"); > > + > > + ret = read(sock, &buf, sizeof(int)); > > + BUG_ON(ret <= 0, "read(sock)"); > > + > > + BUG_ON(*smap == 0x22222BAD, "MAP_POPULATE didn't COW > > private page"); > > + BUG_ON(*smap != 0xdeadbabe, "mapping was corrupted"); > > + > > + return 0; > > +} > > + > > +int main(int argc, char **argv) > > +{ > > + int sock[2], child, ret; > > + FILE *ftmp; > > + unsigned long *smap; > > + > > + ftmp = tmpfile(); > > + BUG_ON(ftmp == 0, "tmpfile()"); > > + > > + ret = ftruncate(fileno(ftmp), MMAP_SZ); > > + BUG_ON(ret, "ftruncate()"); > > + > > + smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE, > > + MAP_SHARED, fileno(ftmp), 0); > > + BUG_ON(smap == MAP_FAILED, "mmap()"); > > + > > + *smap = 0xdeadbabe; > > + /* Probably unnecessary, but let it be. */ > > + ret = msync(smap, MMAP_SZ, MS_SYNC); > > + BUG_ON(ret, "msync()"); > > + > > + ret = socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sock); > > + BUG_ON(ret, "socketpair()"); > > + > > + child = fork(); > > + BUG_ON(child == -1, "fork()"); > > + > > + if (child) { > > + ret = close(sock[0]); > > + BUG_ON(ret, "close()"); > > + > > + return parent_f(sock[1], smap, child); > > + } > > + > > + ret = close(sock[1]); > > + BUG_ON(ret, "close()"); > > + > > + return child_f(sock[0], smap, fileno(ftmp)); > > +} > > diff --git a/tools/testing/selftests/vm/run_vmtests > > b/tools/testing/selftests/vm/run_vmtests > > index 88cbe5575f0c..584a91ae4a8f 100755 > > --- a/tools/testing/selftests/vm/run_vmtests > > +++ b/tools/testing/selftests/vm/run_vmtests > > @@ -168,6 +168,17 @@ else > > fi > > > > echo "--------------------" > > +echo "running map_populate" > > +echo "--------------------" > > +./map_populate > > +if [ $? -ne 0 ]; then > > + echo "[FAIL]" > > + exitcode=1 > > +else > > + echo "[PASS]" > > +fi > > + > > +echo "--------------------" > > echo "running mlock2-tests" > > echo "--------------------" > > ./mlock2-tests > > > > thanks, > -- Shuah -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 2018-08-01 at 17:12 -0700, Andrew Morton wrote: > On Thu, 2 Aug 2018 00:36:36 +0100 Dmitry Safonov <dima@arista.com> > wrote: > > > As many other projects, we use some shmalloc allocator. > > At some point we need to make a part of allocated pages back > > private to > > process. And it should be populated straight away. > > Check that (MAP_PRIVATE | MAP_POPULATE) actually copies the private > > page. > > > > ... > > > > --- /dev/null > > +++ b/tools/testing/selftests/vm/map_populate.c > > > > ... > > > > +#define BUG_ON(condition, description) > > \ > > + do { > > \ > > + if (condition) { > > \ > > + fprintf(stderr, "[FAIL]\t%s:%d\t%s:%s\n", > > __func__, \ > > + __LINE__, (description), > > strerror(errno)); \ > > + exit(1); > > \ > > + } > > \ > > + } while (0) > > This is userspace. Why not use assert()? I wanted to print errno too. Of cause it's possible to get it from coredump - but I think it's easier if you get buildbot reply to see what the error is from the log. > > > > > ... > > > > +int main(int argc, char **argv) > > +{ > > + int sock[2], child, ret; > > + FILE *ftmp; > > + unsigned long *smap; > > + > > + ftmp = tmpfile(); > > Seems odd to putz around with stdio when you just want the fd. > mkstemp(), maybe? It needs a template and unlink() call.. I can do it. I initially thought about memfd_create(), can change it that way. The only downside is that it will be syscall(NR_memfd_create,...) > > > + BUG_ON(ftmp == 0, "tmpfile()"); > > + > > + ret = ftruncate(fileno(ftmp), MMAP_SZ); > > + BUG_ON(ret, "ftruncate()"); > > + > > + smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE, > > + MAP_SHARED, fileno(ftmp), 0); > > + BUG_ON(smap == MAP_FAILED, "mmap()"); > > + > > + *smap = 0xdeadbabe; > > + /* Probably unnecessary, but let it be. */ > > + ret = msync(smap, MMAP_SZ, MS_SYNC); > > + BUG_ON(ret, "msync()"); > > + > > + ret = socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sock); > > + BUG_ON(ret, "socketpair()"); > > + > > + child = fork(); > > + BUG_ON(child == -1, "fork()"); > > + > > + if (child) { > > + ret = close(sock[0]); > > + BUG_ON(ret, "close()"); > > + > > + return parent_f(sock[1], smap, child); > > + } > > + > > + ret = close(sock[1]); > > + BUG_ON(ret, "close()"); > > + > > + return child_f(sock[0], smap, fileno(ftmp)); > > +} > > > > ... > > -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore index 342c7bc9dc8c..af5ff83f6d7f 100644 --- a/tools/testing/selftests/vm/.gitignore +++ b/tools/testing/selftests/vm/.gitignore @@ -1,6 +1,7 @@ hugepage-mmap hugepage-shm map_hugetlb +map_populate thuge-gen compaction_test mlock2-tests diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile index fdefa2295ddc..9881876d2aa0 100644 --- a/tools/testing/selftests/vm/Makefile +++ b/tools/testing/selftests/vm/Makefile @@ -12,6 +12,7 @@ TEST_GEN_FILES += gup_benchmark TEST_GEN_FILES += hugepage-mmap TEST_GEN_FILES += hugepage-shm TEST_GEN_FILES += map_hugetlb +TEST_GEN_FILES += map_populate TEST_GEN_FILES += mlock-random-test TEST_GEN_FILES += mlock2-tests TEST_GEN_FILES += on-fault-limit diff --git a/tools/testing/selftests/vm/map_populate.c b/tools/testing/selftests/vm/map_populate.c new file mode 100644 index 000000000000..df3eacc8eecb --- /dev/null +++ b/tools/testing/selftests/vm/map_populate.c @@ -0,0 +1,113 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2018 Dmitry Safonov, Arista Networks + * + * MAP_POPULATE | MAP_PRIVATE should COW VMA pages. + */ + +#define _GNU_SOURCE +#include <errno.h> +#include <fcntl.h> +#include <sys/mman.h> +#include <sys/socket.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#ifndef MMAP_SZ +#define MMAP_SZ 4096 +#endif + +#define BUG_ON(condition, description) \ + do { \ + if (condition) { \ + fprintf(stderr, "[FAIL]\t%s:%d\t%s:%s\n", __func__, \ + __LINE__, (description), strerror(errno)); \ + exit(1); \ + } \ + } while (0) + +static int parent_f(int sock, unsigned long *smap, int child) +{ + int status, ret; + + ret = read(sock, &status, sizeof(int)); + BUG_ON(ret <= 0, "read(sock)"); + + *smap = 0x22222BAD; + ret = msync(smap, MMAP_SZ, MS_SYNC); + BUG_ON(ret, "msync()"); + + ret = write(sock, &status, sizeof(int)); + BUG_ON(ret <= 0, "write(sock)"); + + waitpid(child, &status, 0); + BUG_ON(!WIFEXITED(status), "child hasn't suicide by own will"); + + return WEXITSTATUS(status); +} + +static int child_f(int sock, unsigned long *smap, int fd) +{ + int ret, buf = 0; + + smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_POPULATE, fd, 0); + BUG_ON(smap == MAP_FAILED, "mmap()"); + + BUG_ON(*smap != 0xdeadbabe, "MAP_PRIVATE | MAP_POPULATE changed file"); + + ret = write(sock, &buf, sizeof(int)); + BUG_ON(ret <= 0, "write(sock)"); + + ret = read(sock, &buf, sizeof(int)); + BUG_ON(ret <= 0, "read(sock)"); + + BUG_ON(*smap == 0x22222BAD, "MAP_POPULATE didn't COW private page"); + BUG_ON(*smap != 0xdeadbabe, "mapping was corrupted"); + + return 0; +} + +int main(int argc, char **argv) +{ + int sock[2], child, ret; + FILE *ftmp; + unsigned long *smap; + + ftmp = tmpfile(); + BUG_ON(ftmp == 0, "tmpfile()"); + + ret = ftruncate(fileno(ftmp), MMAP_SZ); + BUG_ON(ret, "ftruncate()"); + + smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE, + MAP_SHARED, fileno(ftmp), 0); + BUG_ON(smap == MAP_FAILED, "mmap()"); + + *smap = 0xdeadbabe; + /* Probably unnecessary, but let it be. */ + ret = msync(smap, MMAP_SZ, MS_SYNC); + BUG_ON(ret, "msync()"); + + ret = socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sock); + BUG_ON(ret, "socketpair()"); + + child = fork(); + BUG_ON(child == -1, "fork()"); + + if (child) { + ret = close(sock[0]); + BUG_ON(ret, "close()"); + + return parent_f(sock[1], smap, child); + } + + ret = close(sock[1]); + BUG_ON(ret, "close()"); + + return child_f(sock[0], smap, fileno(ftmp)); +} diff --git a/tools/testing/selftests/vm/run_vmtests b/tools/testing/selftests/vm/run_vmtests index 88cbe5575f0c..584a91ae4a8f 100755 --- a/tools/testing/selftests/vm/run_vmtests +++ b/tools/testing/selftests/vm/run_vmtests @@ -168,6 +168,17 @@ else fi echo "--------------------" +echo "running map_populate" +echo "--------------------" +./map_populate +if [ $? -ne 0 ]; then + echo "[FAIL]" + exitcode=1 +else + echo "[PASS]" +fi + +echo "--------------------" echo "running mlock2-tests" echo "--------------------" ./mlock2-tests
As many other projects, we use some shmalloc allocator. At some point we need to make a part of allocated pages back private to process. And it should be populated straight away. Check that (MAP_PRIVATE | MAP_POPULATE) actually copies the private page. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Hua Zhong <hzhong@arista.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Stuart Ritchie <sritchie@arista.com> Cc: linux-kselftest@vger.kernel.org Signed-off-by: Dmitry Safonov <dima@arista.com> --- tools/testing/selftests/vm/.gitignore | 1 + tools/testing/selftests/vm/Makefile | 1 + tools/testing/selftests/vm/map_populate.c | 113 ++++++++++++++++++++++++++++++ tools/testing/selftests/vm/run_vmtests | 11 +++ 4 files changed, 126 insertions(+) create mode 100644 tools/testing/selftests/vm/map_populate.c