From: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Date: Tue, 9 Feb 2021 18:51:50 +0000 (+0100)
Subject: sd-netlink: pahole optimization of sd_netlink_slot
X-Git-Tag: v248-rc1~166^2~8
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=399f74c79d27e06f22908bfbffbb28e207f5810b;p=thirdparty%2Fsystemd.git

sd-netlink: pahole optimization of sd_netlink_slot

By rearranging the fields, we can avoid one of the holes (on amd64).
By adding more space for .type, -EINVAL can be used as a value later on.
The structure is reduced from 96 to 88 bytes (on amd64).

Text size is also smaller:
-rwxrwxr-x 1 zbyszek zbyszek 4109832 Feb  9 19:50 build/libsystemd.so.0.30.0
-rwxrwxr-x 1 zbyszek zbyszek 4109792 Feb  9 19:51 build/libsystemd.so.0.30.0
---

diff --git a/src/libsystemd/sd-netlink/netlink-internal.h b/src/libsystemd/sd-netlink/netlink-internal.h
index efd0cf93358..9159f94dd9a 100644
--- a/src/libsystemd/sd-netlink/netlink-internal.h
+++ b/src/libsystemd/sd-netlink/netlink-internal.h
@@ -38,12 +38,12 @@ typedef enum NetlinkSlotType {
 
 struct sd_netlink_slot {
         unsigned n_ref;
+        NetlinkSlotType type:8;
+        bool floating;
         sd_netlink *netlink;
         void *userdata;
         sd_netlink_destroy_t destroy_callback;
-        NetlinkSlotType type:2;
 
-        bool floating:1;
         char *description;
 
         LIST_FIELDS(sd_netlink_slot, slots);