The current "ADD" vs "ADDQ" is confusing because when thinking in terms
of appending at the end of a list, "ADD" naturally comes to mind, but
here it does the opposite, it inserts. Several times already it's been
incorrectly used where ADDQ was expected, the latest of which was a
fortunate accident explained in 6fa922562 ("CLEANUP: stream: explain
why we queue the stream at the head of the server list").
Let's use more explicit (but slightly longer) names now:
LIST_ADD -> LIST_INSERT
LIST_ADDQ -> LIST_APPEND
LIST_ADDED -> LIST_INLIST
LIST_DEL -> LIST_DELETE
The same is true for MT_LISTs, including their "TRY" variant.
LIST_DEL_INIT keeps its short name to encourage to use it instead of the
lazier LIST_DELETE which is often less safe.
The change is large (~674 non-comment entries) but is mechanical enough
to remain safe. No permutation was performed, so any out-of-tree code
can easily map older names to new ones.
The list doc was updated.
Introduction of a new function in the LRU cache source file.
Purpose of this function is to be used to delete a number of entries in
the cache. 'number' is defined by the caller and the key removed are
taken at the tail of the tree
Commit 7810ad7 ("BUG/MAJOR: lru: fix unconditional call to free due to
unexpected semi-colon") was not enough, it happens that the free() is
not performed at the right place because if the evicted node is recycled,
we must also release its data before it gets overwritten.
No backport is needed.
Dmitry Sivachenko reported the following build warning using Clang, which
is a real bug :
src/lru.c:133:32: warning: if statement has empty body [-Wempty-body]
if (old->data && old->free);
^
It results in calling old->free(old->data) even when old->free is NULL,
hence crashing on cached patterns.
The same bug appears a few lines below in lru64_destroy() :
src/lru.c:195:33: warning: if statement has empty body [-Wempty-body]
if (elem->data && elem->free);
^
Both were introduced in 1.6-dev2 with commit f90ac55 ("MINOR: lru: Add the
possibility to free data when an item is removed"), so no backport is needed.
It lookup a key in a LRU cache for use with specified domain and revision. It
differs from lru64_get as it does not create missing keys. The function returns
NULL if an error or a cache miss occurs.
Now, When a item is committed in an LRU tree, you can define a function to free
data owned by this item. This function will be called when the item is removed
from the LRU tree or when the tree is destroyed..
This will be usable to implement some maps/acl caches for heavy datasets
loaded from files (mostly regex-based but in general anything that cannot
be indexed in a tree).
