[PULL,17/18] virtio-mem: don't warn about THP sizes on a kernel without THP support

Commit Message

Michael S. Tsirkin Sept. 11, 2024, 1:52 p.m. UTC

From: David Hildenbrand <[e-mail]>

If the config directory in sysfs does not exist at all, we are dealing
with a system that does not support THPs. Simply use 1 MiB block size
then, instead of warning "Could not detect THP size, falling back to
..." and falling back to the default THP size.

Cc: "Michael S. Tsirkin" <[e-mail]>
Cc: Gavin Shan <[e-mail]>
Cc: Juraj Marcin <[e-mail]>
Signed-off-by: David Hildenbrand <[e-mail]>
Message-Id: <[e-mail]>
Reviewed-by: Michael S. Tsirkin <[e-mail]>
Signed-off-by: Michael S. Tsirkin <[e-mail]>
---
 hw/virtio/virtio-mem.c | 7 +++++++
 1 file changed, 7 insertions(+)

Patch

diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
index ef64bf1b4a..4075f3d4ce 100644
--- a/hw/virtio/virtio-mem.c
+++ b/hw/virtio/virtio-mem.c
@@ -88,6 +88,7 @@  static uint32_t virtio_mem_default_thp_size(void)
 static uint32_t thp_size;
 
 #define HPAGE_PMD_SIZE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size"
+#define HPAGE_PATH "/sys/kernel/mm/transparent_hugepage/"
 static uint32_t virtio_mem_thp_size(void)
 {
     gchar *content = NULL;
@@ -98,6 +99,12 @@  static uint32_t virtio_mem_thp_size(void)
         return thp_size;
     }
 
+    /* No THP -> no restrictions. */
+    if (!g_file_test(HPAGE_PATH, G_FILE_TEST_EXISTS)) {
+        thp_size = VIRTIO_MEM_MIN_BLOCK_SIZE;
+        return thp_size;
+    }
+
     /*
      * Try to probe the actual THP size, fallback to (sane but eventually
      * incorrect) default sizes.