fib algo: do not reallocate datapath index for datapath ptr update.

Fib algo uses a per-family array indexed by the fibnum to store
 lookup function pointers and per-fib data.

Each algorithm rebuild currently requires re-allocating this array
 to support atomic change of two pointers.

As in reality most of the changes actually involve changing only
 data pointer, add a shortcut performing in-flight pointer update.

MFC after:	2 weeks
This commit is contained in:
Alexander V. Chernikov 2021-04-18 16:03:58 +01:00
parent e2f79d9e51
commit 0abb6ff590

View File

@ -1561,6 +1561,17 @@ replace_rtables_family(struct fib_dp **pdp, struct fib_data *fd, struct fib_dp *
FIB_MOD_LOCK();
old_fdh = get_fib_dp_header(*pdp);
if (old_fdh->fdh_idx[fd->fd_fibnum].f == dp->f) {
/*
* Function is the same, data pointer needs update.
* Perform in-line replace without reallocation.
*/
old_fdh->fdh_idx[fd->fd_fibnum].arg = dp->arg;
FD_PRINTF(LOG_DEBUG, fd, "FDH %p inline update", old_fdh);
FIB_MOD_UNLOCK();
return (true);
}
new_fdh = alloc_fib_dp_array(old_fdh->fdh_num_tables, false);
FD_PRINTF(LOG_DEBUG, fd, "OLD FDH: %p NEW FDH: %p", old_fdh, new_fdh);
if (new_fdh == NULL) {