configuration_validate_capabilities() allocates a bitmap on the heap to track source capabilities via bitmap_new()/g_free(). Since MIGRATION_CAPABILITY__MAX is a small compile-time constant (< 64), a heap allocation for a bitmap this small is wasteful: it adds malloc/free overhead and a potential cache miss for a transient 8-byte allocation.
Replace with DECLARE_BITMAP() on the stack and bitmap_zero() to initialize. This eliminates the heap round-trip entirely. Signed-off-by: Bin Guo <[email protected]> --- migration/savevm.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/migration/savevm.c b/migration/savevm.c index d1dd696c17..23adaf9dd9 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -347,10 +347,10 @@ static bool configuration_validate_capabilities(SaveState *state) { bool ret = true; MigrationState *s = migrate_get_current(); - unsigned long *source_caps_bm; + DECLARE_BITMAP(source_caps_bm, MIGRATION_CAPABILITY__MAX); int i; - source_caps_bm = bitmap_new(MIGRATION_CAPABILITY__MAX); + bitmap_zero(source_caps_bm, MIGRATION_CAPABILITY__MAX); for (i = 0; i < state->caps_count; i++) { MigrationCapability capability = state->capabilities[i]; set_bit(capability, source_caps_bm); @@ -373,7 +373,6 @@ static bool configuration_validate_capabilities(SaveState *state) } } - g_free(source_caps_bm); return ret; } -- 2.50.1 (Apple Git-155)
