No need to include the full tree management code, type files only
need the definitions. Doing so reduces the whole code size by around
3.6% and the build time is down to just 6s.
The output of "show map/acl" now contains the 'entry_cnt' value that
represents the count of all the entries for each map/acl, not just the
active ones, which means that it also includes entries currently being
added.
It does not require heavy deletion from the expr anymore, so we can now
turn this to a single-linked list since most of the time we want to delete
all instances of a given pattern from the head. By doing so we save 32 bytes
of memory per pattern. The pat_unlink_from_head() function was adjusted
accordingly.
Right now it's not possible to perform a safe reload because we don't
know what patterns were recently added or were already present. This
patch adds a generation counter to the reference patterns so that it
is possible to know what generation of the reference they were loaded
with. A reference now has two generations, the current one, used for
all additions, and the next one, allocated to those wishing to update
the contents. The generation wraps at 2^32 so comparisons must be made
relative to the current position.
The idea will be that upon full reload, the caller will first get a new
generation ID, will insert all new patterns using it, will then switch
the current ID to the new one, and will delete all entries older than
the current ID. This has the benefit of supporting chunked updates that
remain consistent and that won't block the whole process for ages like
pat_ref_reload() currently does.
These ones are not used anymore, so let's remove them to remove a bit
of the complexity. The ACL keyword's delete() function could be removed
as well, though most keyword declarations are positional and we have a
high risk of introducing a mistake here, so let's not touch the ACL part.
This is the next step in speeding up entry removal. Now we don't scan
the whole lists or trees for elements pointing to the target reference,
instead we start from the reference and delete all linked patterns.
This simplifies some delete functions since we don't need anymore to
delete multiple times from an expression since all nodes appear after
the reference element. We can now have one generic list and one generic
tree deletion function.
This required the replacement of pattern_delete() with an open-coded
version since we now need to lock all expressions first before proceeding.
This means there is a high risk of lock inversion here but given that the
expressions are always scanned in the same order from the same head, this
must not happen.
Now deleting first entries is instantaneous, and it's still slow to
delete the last ones when looking up their ID since it still requires
to look them up by a full scan, but it's already way faster than
previously. Typically removing the last 10 IP from a 20M entries ACL
with a full-scan each took less than 2 seconds.
It would be technically possible to make use of indexed entries to
speed up most lookups for removal by value (e.g. IP addresses) but
that's for later.
There is a data model issue in the current pattern design that makes
pattern deletion extremely expensive: there's no direct way from a
reference to access all indexed occurrences. As such, the only way
to remove all indexed entries corresponding to a reference update
is to scan all expressions's lists and trees to find a link to the
reference. While this was possibly OK when map removal was not
common and most maps were small, this is not conceivable anymore
with GeoIP maps containing 10M+ entries and del-map operations that
are triggered from http-request rulesets.
This patch introduces two list heads from the pattern reference, one
for the objects linked by lists and one for those linked by tree node.
Ideally a single list would be enough but the linked elements are too
much unrelated to be distinguished at the moment, so we'll need two
lists. However for the long term a single-linked list will suffice but
for now it's not possible due to the way elements are removed from
expressions. As such this patch adds 32 bytes of memory usage per
reference plus 16 per indexed entry, but both will be cut in half
later.
The links are not yet used for deletion, this patch only ensures the
list is always consistent.
Now we have a single prune() function to act on an expression, and one
delete function for the lists and one for the trees. The presence of a
pointer in the lists is enough to warrant a free, and we rely on the
PAT_SF_REGFREE flag to decide whether to free using free() or regfree().
Currently we have no way to know how to delete/prune a pattern in a
generic way. A pattern doesn't contain its own type so we don't know
what function to call. Tree nodes are roughly OK but not lists where
regex are possible. Let's add one new bit for sflags at index time to
indicate that regex_free() will be needed upon deletion. It's not used
for now.
It's not possible to uniquely update a single expression without updating
the pattern reference, I don't know why we've put the revision in the
expression back then, given that it in fact provides an update for a
full pattern. Let's move the revision into the reference's head instead.
A few structures were slightly rearranged in order to plug some holes
left around the locks. Sizes ranging from 8 to 32 bytes could be saved
depending on the structures. No performance difference was noticed (none
was expected there), though memory usage might be slightly reduced in
some rare cases.
There are list definitions everywhere in the code, let's drop the need
for including list-t.h to declare them. The rest of the list manipulation
is huge however and not needed everywhere so using the list walking macros
still requires to include list.h.
This patch fixes all the leftovers from the include cleanup campaign. There
were not that many (~400 entries in ~150 files) but it was definitely worth
doing it as it revealed a few duplicates.
The struct sample_data is used by pattern, map and vars, and currently
requires to include sample-t which comes with many other dependencies.
Let's move sample_data into its own file to shorten the dependency tree.
This revealed a number of issues in adjacent files which were hidden by
the fact that sample-t.h brought everything that was missing.
This one is particularly tricky to move because everyone uses it
and it depends on a lot of other types. For example it cannot include
arg-t.h and must absolutely only rely on forward declarations to avoid
dependency loops between vars -> sample_data -> arg. In order to address
this one, it would be nice to split the sample_data part out of sample.h.
It was moved as-is, except for extern declaration of pattern_reference.
A few C files used to include it but didn't need it anymore after having
been split apart so this was cleaned.
