An upcoming commit will declare a bitmap on the stack, rather than heap
allocating it, which means that it is not possible to use a function call
in the declaration.
Signed-off-by: Ben Pfaff <blp@nicira.com>
Casts are sometimes necessary. One common reason that they are necessary
is for discarding a "const" qualifier. However, this can impede
maintenance: if the type of the expression being cast changes, then the
presence of the cast can hide a necessary change in the code that does the
cast. Using CONST_CAST, instead of a bare cast, makes these changes
visible.
Inspired by my own work elsewhere:
http://git.savannah.gnu.org/cgit/pspp.git/tree/src/libpspp/cast.h#n80
Signed-off-by: Ben Pfaff <blp@nicira.com>
Replaced all instances of Nicira Networks(, Inc) to Nicira, Inc.
Feature #10593
Signed-off-by: Raju Subramanian <rsubramanian@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
These new semantics are less efficient in the case where the flood_vlans
actually changed, but that should be very rare.
There are no advantages to this change on its own, but upcoming commits
will add multiple layers between the code supplying the flood_vlans and
actually calling mac_learning_set_flood_vlans(). Consistency in this
multilayered interface seems valuable, and the rest of it does not transfer
ownership from the caller to the callee.
Until now, each part of a transaction commit that is interested in whether
a column's value has changed has had to do a comparison of the old and new
values itself. There can be several interested parties per commit
(generally one for file storage and one for each remove OVSDB connection),
so this seems like too much redundancy. This commit adds a bitmap
to struct ovsdb_txn_row that tracks whether a column's value has actually
changed, to reduce this overhead.
As a convenient side effect of doing these checks up front, it then
becomes easily possible to drop txn_rows (and txn_tables and entire txns)
that become no-ops. (This probably fixes bug #2400, which reported that
some no-ops actually report updates over monitors.)
bitmap_scan() can be optimized significantly for the case of a sparse
bitmap but it doesn't seem worth the additional overhead of writing a test
unless and until we show that it's a useful optimization in practice.
ROUND_UP rounds up to a multiple of a given value. That means that
bitmap_allocate() was allocating one byte for each bit in the bitmap,
which is clearly excessive.
Instead, just allocate one bit for every bit in the bitmap.
