diff mbox series

[PULL,v2,33/55] util/oslib-posix: Avoid creating a single thread with MADV_POPULATE_WRITE

Message ID 20220107102526.39238-34-mst@redhat.com
State New
Headers show
Series [PULL,v2,01/55] virtio-mem: Don't skip alignment checks when warning about block size | expand

Commit Message

Michael S. Tsirkin Jan. 7, 2022, 11:04 a.m. UTC 
From: 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.

Reviewed-by: Pankaj Gupta <pankaj.gupta@ionos.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20211217134611.31172-6-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 util/oslib-posix.c | 8 ++++++++
 1 file changed, 8 insertions(+)
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Patch

diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 67c08a425e..efa4f96d56 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -564,6 +564,14 @@  static int 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 -errno;
+            }
+            return 0;
+        }
         touch_fn = do_madv_populate_write_pages;
     } else {
         touch_fn = do_touch_pages;