[v3,5/7] hostmem: Factor out applying settings

Commit Message

“William Roche Nov. 25, 2024, 2:27 p.m. UTC

From: David Hildenbrand <[e-mail]>

We want to reuse the functionality when remapping or resizing RAM.

Signed-off-by: David Hildenbrand <[e-mail]>
Signed-off-by: William Roche <[e-mail]>
---
 backends/hostmem.c | 155 ++++++++++++++++++++++++---------------------
 1 file changed, 82 insertions(+), 73 deletions(-)

Patch

diff --git a/backends/hostmem.c b/backends/hostmem.c
index 181446626a..bf85d716e5 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -36,6 +36,87 @@  QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_BIND != MPOL_BIND);
 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_INTERLEAVE != MPOL_INTERLEAVE);
 #endif
 
+static void host_memory_backend_apply_settings(HostMemoryBackend *backend,
+                                               void *ptr, uint64_t size,
+                                               Error **errp)
+{
+    bool async = !phase_check(PHASE_LATE_BACKENDS_CREATED);
+
+    if (backend->merge) {
+        qemu_madvise(ptr, size, QEMU_MADV_MERGEABLE);
+    }
+    if (!backend->dump) {
+        qemu_madvise(ptr, size, QEMU_MADV_DONTDUMP);
+    }
+#ifdef CONFIG_NUMA
+    unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
+    /* lastbit == MAX_NODES means maxnode = 0 */
+    unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
+    /*
+     * Ensure policy won't be ignored in case memory is preallocated
+     * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
+     * this doesn't catch hugepage case.
+     */
+    unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
+    int mode = backend->policy;
+
+    /*
+     * Check for invalid host-nodes and policies and give more verbose
+     * error messages than mbind().
+     */
+    if (maxnode && backend->policy == MPOL_DEFAULT) {
+        error_setg(errp, "host-nodes must be empty for policy default,"
+                   " or you should explicitly specify a policy other"
+                   " than default");
+        return;
+    } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
+        error_setg(errp, "host-nodes must be set for policy %s",
+                   HostMemPolicy_str(backend->policy));
+        return;
+    }
+
+    /*
+     * We can have up to MAX_NODES nodes, but we need to pass maxnode+1
+     * as argument to mbind() due to an old Linux bug (feature?) which
+     * cuts off the last specified node. This means backend->host_nodes
+     * must have MAX_NODES+1 bits available.
+     */
+    assert(sizeof(backend->host_nodes) >=
+           BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
+    assert(maxnode <= MAX_NODES);
+
+#ifdef HAVE_NUMA_HAS_PREFERRED_MANY
+    if (mode == MPOL_PREFERRED && numa_has_preferred_many() > 0) {
+        /*
+         * Replace with MPOL_PREFERRED_MANY otherwise the mbind() below
+         * silently picks the first node.
+         */
+        mode = MPOL_PREFERRED_MANY;
+    }
+#endif
+
+    if (maxnode &&
+        mbind(ptr, size, mode, backend->host_nodes, maxnode + 1, flags)) {
+        if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
+            error_setg_errno(errp, errno,
+                             "cannot bind memory to host NUMA nodes");
+            return;
+        }
+    }
+#endif
+    /*
+     * Preallocate memory after the NUMA policy has been instantiated.
+     * This is necessary to guarantee memory is allocated with
+     * specified NUMA policy in place.
+     */
+    if (backend->prealloc &&
+        !qemu_prealloc_mem(memory_region_get_fd(&backend->mr),
+                           ptr, size, backend->prealloc_threads,
+                           backend->prealloc_context, async, errp)) {
+        return;
+    }
+}
+
 char *
 host_memory_backend_get_name(HostMemoryBackend *backend)
 {
@@ -337,7 +418,6 @@  host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
     void *ptr;
     uint64_t sz;
     size_t pagesize;
-    bool async = !phase_check(PHASE_LATE_BACKENDS_CREATED);
 
     if (!bc->alloc) {
         return;
@@ -357,78 +437,7 @@  host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
         return;
     }
 
-    if (backend->merge) {
-        qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
-    }
-    if (!backend->dump) {
-        qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
-    }
-#ifdef CONFIG_NUMA
-    unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
-    /* lastbit == MAX_NODES means maxnode = 0 */
-    unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
-    /*
-     * Ensure policy won't be ignored in case memory is preallocated
-     * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
-     * this doesn't catch hugepage case.
-     */
-    unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
-    int mode = backend->policy;
-
-    /* check for invalid host-nodes and policies and give more verbose
-     * error messages than mbind(). */
-    if (maxnode && backend->policy == MPOL_DEFAULT) {
-        error_setg(errp, "host-nodes must be empty for policy default,"
-                   " or you should explicitly specify a policy other"
-                   " than default");
-        return;
-    } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
-        error_setg(errp, "host-nodes must be set for policy %s",
-                   HostMemPolicy_str(backend->policy));
-        return;
-    }
-
-    /*
-     * We can have up to MAX_NODES nodes, but we need to pass maxnode+1
-     * as argument to mbind() due to an old Linux bug (feature?) which
-     * cuts off the last specified node. This means backend->host_nodes
-     * must have MAX_NODES+1 bits available.
-     */
-    assert(sizeof(backend->host_nodes) >=
-           BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
-    assert(maxnode <= MAX_NODES);
-
-#ifdef HAVE_NUMA_HAS_PREFERRED_MANY
-    if (mode == MPOL_PREFERRED && numa_has_preferred_many() > 0) {
-        /*
-         * Replace with MPOL_PREFERRED_MANY otherwise the mbind() below
-         * silently picks the first node.
-         */
-        mode = MPOL_PREFERRED_MANY;
-    }
-#endif
-
-    if (maxnode &&
-        mbind(ptr, sz, mode, backend->host_nodes, maxnode + 1, flags)) {
-        if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
-            error_setg_errno(errp, errno,
-                             "cannot bind memory to host NUMA nodes");
-            return;
-        }
-    }
-#endif
-    /*
-     * Preallocate memory after the NUMA policy has been instantiated.
-     * This is necessary to guarantee memory is allocated with
-     * specified NUMA policy in place.
-     */
-    if (backend->prealloc && !qemu_prealloc_mem(memory_region_get_fd(&backend->mr),
-                                                ptr, sz,
-                                                backend->prealloc_threads,
-                                                backend->prealloc_context,
-                                                async, errp)) {
-        return;
-    }
+    host_memory_backend_apply_settings(backend, ptr, sz, errp);
 }
 
 static bool