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authorAndrea Arcangeli <aarcange@redhat.com>2017-10-13 15:57:54 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-10-13 16:18:32 -0700
commit7ddd8faf4399ab4f4edad5604eab35f8a87caf02 (patch)
tree51d651f20cdf07d8e7f01f8e23e371b5809c352d
parent064f0e9302af4f4ab5e9dca03a5a77d6bebfd35e (diff)
downloadlinux-sh-7ddd8faf4399ab4f4edad5604eab35f8a87caf02.tar.gz
userfaultfd: selftest: exercise -EEXIST only in background transfer
I was stress testing some backports and with high load, after some time, the latest version of the selftest showed some false positive in connection with the uffdio_copy_retry. This seems to fix it while still exercising -EEXIST in the background transfer once in a while. The fork child will quit after the last UFFDIO_COPY is run, so a repeated UFFDIO_COPY may not return -EEXIST. This change restricts the -EEXIST stress to the background transfer where the memory can't go away from under it. Also updated uffdio_zeropage, so the interface is consistent. Link: http://lkml.kernel.org/r/20171004171541.1495-2-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--tools/testing/selftests/vm/userfaultfd.c25
1 files changed, 20 insertions, 5 deletions
diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index a2c53a3d223d..de2f9ec8a87f 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -397,7 +397,7 @@ static void retry_copy_page(int ufd, struct uffdio_copy *uffdio_copy,
}
}
-static int copy_page(int ufd, unsigned long offset)
+static int __copy_page(int ufd, unsigned long offset, bool retry)
{
struct uffdio_copy uffdio_copy;
@@ -418,7 +418,7 @@ static int copy_page(int ufd, unsigned long offset)
fprintf(stderr, "UFFDIO_COPY unexpected copy %Ld\n",
uffdio_copy.copy), exit(1);
} else {
- if (test_uffdio_copy_eexist) {
+ if (test_uffdio_copy_eexist && retry) {
test_uffdio_copy_eexist = false;
retry_copy_page(ufd, &uffdio_copy, offset);
}
@@ -427,6 +427,16 @@ static int copy_page(int ufd, unsigned long offset)
return 0;
}
+static int copy_page_retry(int ufd, unsigned long offset)
+{
+ return __copy_page(ufd, offset, true);
+}
+
+static int copy_page(int ufd, unsigned long offset)
+{
+ return __copy_page(ufd, offset, false);
+}
+
static void *uffd_poll_thread(void *arg)
{
unsigned long cpu = (unsigned long) arg;
@@ -544,7 +554,7 @@ static void *background_thread(void *arg)
for (page_nr = cpu * nr_pages_per_cpu;
page_nr < (cpu+1) * nr_pages_per_cpu;
page_nr++)
- copy_page(uffd, page_nr * page_size);
+ copy_page_retry(uffd, page_nr * page_size);
return NULL;
}
@@ -779,7 +789,7 @@ static void retry_uffdio_zeropage(int ufd,
}
}
-static int uffdio_zeropage(int ufd, unsigned long offset)
+static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
{
struct uffdio_zeropage uffdio_zeropage;
int ret;
@@ -814,7 +824,7 @@ static int uffdio_zeropage(int ufd, unsigned long offset)
fprintf(stderr, "UFFDIO_ZEROPAGE unexpected %Ld\n",
uffdio_zeropage.zeropage), exit(1);
} else {
- if (test_uffdio_zeropage_eexist) {
+ if (test_uffdio_zeropage_eexist && retry) {
test_uffdio_zeropage_eexist = false;
retry_uffdio_zeropage(ufd, &uffdio_zeropage,
offset);
@@ -830,6 +840,11 @@ static int uffdio_zeropage(int ufd, unsigned long offset)
return 0;
}
+static int uffdio_zeropage(int ufd, unsigned long offset)
+{
+ return __uffdio_zeropage(ufd, offset, false);
+}
+
/* exercise UFFDIO_ZEROPAGE */
static int userfaultfd_zeropage_test(void)
{