util: Make qemu_prealloc_mem() optionally consume a ThreadContext

... and implement it under POSIX. When a ThreadContext is provided,
create new threads via the context such that these new threads obtain a
properly configured CPU affinity.

Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Message-Id: <20221014134720.168738-6-david@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>

1 files changed, 14 insertions, 6 deletions

diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 28305cdea3..59a891b6a8 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -419,7 +419,8 @@ static inline int get_memset_num_threads(size_t hpagesize, size_t numpages,
 }
 
 static int touch_all_pages(char *area, size_t hpagesize, size_t numpages,
-                           int max_threads, bool use_madv_populate_write)
+                           int max_threads, ThreadContext *tc,
+                           bool use_madv_populate_write)
 {
     static gsize initialized = 0;
     MemsetContext context = {
@@ -458,9 +459,16 @@ static int touch_all_pages(char *area, size_t hpagesize, size_t numpages,
         context.threads[i].numpages = numpages_per_thread + (i < leftover);
         context.threads[i].hpagesize = hpagesize;
         context.threads[i].context = &context;
-        qemu_thread_create(&context.threads[i].pgthread, "touch_pages",
-                           touch_fn, &context.threads[i],
-                           QEMU_THREAD_JOINABLE);
+        if (tc) {
+            thread_context_create_thread(tc, &context.threads[i].pgthread,
+                                         "touch_pages",
+                                         touch_fn, &context.threads[i],
+                                         QEMU_THREAD_JOINABLE);
+        } else {
+            qemu_thread_create(&context.threads[i].pgthread, "touch_pages",
+                               touch_fn, &context.threads[i],
+                               QEMU_THREAD_JOINABLE);
+        }
         addr += context.threads[i].numpages * hpagesize;
     }
 
@@ -496,7 +504,7 @@ static bool madv_populate_write_possible(char *area, size_t pagesize)
 }
 
 void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads,
-                       Error **errp)
+                       ThreadContext *tc, Error **errp)
 {
     static gsize initialized;
     int ret;
@@ -537,7 +545,7 @@ void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads,
     }
 
     /* touch pages simultaneously */
-    ret = touch_all_pages(area, hpagesize, numpages, max_threads,
+    ret = touch_all_pages(area, hpagesize, numpages, max_threads, tc,
                           use_madv_populate_write);
     if (ret) {
         error_setg_errno(errp, -ret,