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>
-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;
{
struct uffdio_copy uffdio_copy;
fprintf(stderr, "UFFDIO_COPY unexpected copy %Ld\n",
uffdio_copy.copy), exit(1);
} else {
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);
}
test_uffdio_copy_eexist = false;
retry_copy_page(ufd, &uffdio_copy, offset);
}
+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;
static void *uffd_poll_thread(void *arg)
{
unsigned long cpu = (unsigned long) arg;
for (page_nr = cpu * nr_pages_per_cpu;
page_nr < (cpu+1) * nr_pages_per_cpu;
page_nr++)
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);
-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;
{
struct uffdio_zeropage uffdio_zeropage;
int ret;
fprintf(stderr, "UFFDIO_ZEROPAGE unexpected %Ld\n",
uffdio_zeropage.zeropage), exit(1);
} else {
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);
test_uffdio_zeropage_eexist = false;
retry_uffdio_zeropage(ufd, &uffdio_zeropage,
offset);
+static int uffdio_zeropage(int ufd, unsigned long offset)
+{
+ return __uffdio_zeropage(ufd, offset, false);
+}
+
/* exercise UFFDIO_ZEROPAGE */
static int userfaultfd_zeropage_test(void)
{
/* exercise UFFDIO_ZEROPAGE */
static int userfaultfd_zeropage_test(void)
{