As discussed in https://github.com/scylladb/scylladb/pull/24606#discussion_r2281870939
clear_gently of shared pointers should release the wrapped
object reference and when the object's use_count reaches 1,
the object itself would be cleared_gently, before it's destroyed.
This behavior is similar to the way we clear gently containers
like arrays or vectors, and so it is extended in this patch
to smart pointers like unique_ptr and foreign_ptr.
The unit tests are adjusted respectively to expect the
smart pointers to be reset after clear_gently, plus
the use of `reset()` for `foreign_ptr<shared_ptr<>>` was
replaced by `clear_gently().get()` which now ensures the
reference to a shared object is released, and awaited for,
if it happens on a foreign owner shard, unlike reset of
a foreign_ptr that kicks off destroy of that shared object
in the background on the owner shard - causing flakiness.
Fixes#25723
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Closesscylladb/scylladb#25759
Currently, when a container or smart pointer holds a const payload
type, utils::clear_gently does not detect the object's clear_gently
method as the method is non-const and requires a mutable object,
as in the following example in class tablet_metadata:
```
using tablet_map_ptr = foreign_ptr<lw_shared_ptr<const tablet_map>>;
using table_to_tablet_map = std::unordered_map<table_id, tablet_map_ptr>;
```
That said, when a container is cleared gently the elements it holds
are destroyed anyhow, so we'd like to allow to clear them gently before
destruction.
This change still doesn't allow directly calling utils::clear_gently
an const objects.
And respective unit tests.
Fixes#24605
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Unlike clear_gently of SharedPtr, clear_gently of a
`foreign_ptr<shared_ptr<T>>` calls clear_gently on the contained object
even if it's still shared and may still be in use.
This change examines the foreign shared pointer's use_count
and calls clear_gently on the shard object only when
its use_count reaches 1.
Fixes#25026
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Since set and unordered_set do not allow modifying
their stored object in place, we need to first extract
each object, clear it gently, and only then destroy it.
To achieve that, introduce a new Extractable concept,
that extracts all items in a loop and calls clear_gently
on each extracted item, until the container is empty.
Add respective unit tests for set and unordered_set.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Closesscylladb/scylladb#24608
Add reserve_gently() that can reserve memory without stalling by
repeatedly calling reserve_partial() method of the passed container.
Update the comments of existing reserve_partial() methods to mention
this newly introduced reserve_gently() wrapper.
Also, add test to verify the functionality.
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
get0() dates back from the days where Seastar futures carried tuples, and
get0() was a way to get the first (and usually only) element. Now
it's a distraction, and Seastar is likely to deprecate and remove it.
Replace with seastar::future::get(), which does the same thing.
Implement clear_gently for std:;optional<T>
and seastar::optimized_optional<T> and respective
unit tests.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Otherwise the null pointer is dereferenced.
Add a unit test reproducing the issue
and testing this fix.
Fixes#13636
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
We have enabled the command line options without changing a
single line of code, we only had to replace old include
with scylla_test_case.hh.
Next step is to add x-log-compaction-groups options, which will
determine the number of compaction groups to be used by all
instantiations of replica::table.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
clear_gently of the foreign_ptr needs to run on the owning
shard, so provide a specialization from the SmartPointer
implementation.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Define a bunch of clear_gently methods that asynchronously
clear the contents of containers and allow yielding.
This replaces clear_gently(std::list<T>&) used by row level
repair by a more generic template implementation.
Note that we do not use coroutines in this patch
to facilitate backporting to releases that do not support coroutines
and since a miscompilation bug was hit with clang++ 11 when attempting
to coroutinize this patch (see
https://bugs.llvm.org/show_bug.cgi?id=50345).
Test: stall_free_test(debug)
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
