[PATCH v2 4/6] util/oslib-posix: Avoid creating a single thread with MADV_POPULATE_WRITE

[David Hildenbrand <david@redhat.com>]

Let's simplify the case when we only want a single thread and don't have
to mess with signal handlers.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 util/oslib-posix.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index a1d309d495..1483e985c6 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -568,6 +568,14 @@ static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages,
     }
 
     if (use_madv_populate_write) {
+        /* Avoid creating a single thread for MADV_POPULATE_WRITE */
+        if (context.num_threads == 1) {
+            if (qemu_madvise(area, hpagesize * numpages,
+                             QEMU_MADV_POPULATE_WRITE)) {
+                return true;
+            }
+            return false;
+        }
         touch_fn = do_madv_populate_write_pages;
     } else {
         touch_fn = do_touch_pages;
-- 
2.31.1