bus: reduce calls to KDBUS_CMD_MEMFD_SIZE_SET ioctl

Instead of calling it for each buffer append, increase allocation
exponentially and set the real value only at the end, when sealing off
the memfd.

This should drastically reduce the number of times we invoke the
ioctl().

1 files changed, 1 insertions, 0 deletions

diff --git a/src/libsystemd-bus/bus-message.h b/src/libsystemd-bus/bus-message.h
index a9d42c345a..cd1fb0e546 100644
--- a/src/libsystemd-bus/bus-message.h
+++ b/src/libsystemd-bus/bus-message.h
@@ -65,6 +65,7 @@ struct bus_body_part {
         void *data;
         size_t size;
         size_t mapped;
+        size_t allocated;
         int memfd;
         bool free_this:1;
         bool munmap_this:1;