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@xxxxxxxxxxxxxxxxxxxx> > Cc: Dmitry Safonov <0x7f454c46@xxxxxxxxx> > Cc: Hua Zhong <hzhong@xxxxxxxxxx> > Cc: Shuah Khan <shuah@xxxxxxxxxx> > Cc: Stuart Ritchie <sritchie@xxxxxxxxxx> > Cc: linux-kselftest@xxxxxxxxxxxxxxx > Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx> > --- > 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@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html