Summary:
[Folly] `MemoryIdler::futexWaitUntil`.

Adds `MemoryIdler::futexWaitUntil` that works like `Futex::futexWaitUntil`, in a similar way that `MemoryIdler::futexWait` works like `Futex::futexWait`.

Removes the ability to customize the idle-timeout clock for `MemoryIdler::futexWait` as a side-effect; the idle-timeout is now a pure duration. Now, the clock used with the idle-timeout is the same as the normal deadline clock, so the idle-timeout clock can be set for `MemoryIdler::futexWaitUntil` by providing a deadline with that clock type. This normally would not matter, but it affects the unit-tests.

Reviewed By: djwatson

Differential Revision: D6681679

fbshipit-source-id: e3cf6e71d7530c5877a834b318b423eb91f71eb9

Summary: stop_ can be relaxed everywhere, it implies only an asynchronous signal, not any sort of memory barrier.

Reviewed By: davidtgoldblatt

Differential Revision: D6690079

fbshipit-source-id: 6f193204e1619f9a8adf81db2d46d05954bfbf85

Summary:
[Folly] Cut the `ScopeGuard` alias now that we have `auto`.

This form works because of hidden lifetime extension:
```lang=c++
folly::ScopeGuard guard = folly::makeGuard([] { /*...*/ });
//  ...
//  guard falls out of scope
```
But this form would not work correctly:
```lang=c++
folly::ScopeGuard guard = folly::makeGuard([] { /*...*/ });
std::async(std::launch::async, [guard = std::move(guard)] {});
```
Because `folly::ScopeGuard` is an rvalue-reference-to-base.
We have `auto`, so just remove `folly::ScopeGuard`. This form works correctly:
```lang=c++
auto guard = folly::makeGuard([] { /*...*/ });
std::async(std::launch::async, [guard = std::move(guard)] {});
```

Reviewed By: igorsugak

Differential Revision: D6690070

fbshipit-source-id: 54e32b300d36fce4eb95a59f1828819afe312ec0

Summary:
[Folly] Move `ScopeGuardImpl` and `ScopeGuardImplBase` into the `detail` namespace.

Let them be marked as private implementation details.

Reviewed By: andrewjcg

Differential Revision: D6665317

fbshipit-source-id: 03e8fee6a16338395ec92c582613b053bd9f74ec

Summary:
[Folly] Stop using `ScopeGuardImpl` in `DynamicParser`.

`ScopeGuardImpl` is an impl type that should not be treated as public.

Reviewed By: igorsugak

Differential Revision: D6689835

fbshipit-source-id: aea6c985e40887594c0aeb0c0948fa77c149a89b

Summary:
[Folly] `folly::Init`, RAII variant of `folly::init`.

Use it in `main` used by unit-tests.

Reviewed By: ot

Differential Revision: D6566358

fbshipit-source-id: fb8e5a18fc43eb65e2cbeb070d97094bd413bb96

Summary: Manage retirement of removed segments using hazptr_obj_batch in order to reduce the chances of fragmenting related segments across thread local lists of retired objects of many threads, which could lead to unnecessarily high memory usage.

Reviewed By: djwatson

Differential Revision: D6686697

fbshipit-source-id: 0d786c0f9e0bac2c44183ed3da21619e1feb3d52

Summary:
Since std::array is actually a struct containing an array it technically
requires double braces around its initializer.  The language allows eliding
these braces, and clang doesn't complain about only using a single brace, but
gcc does when using `-Wmissing-braces`.

Reviewed By: yfeldblum

Differential Revision: D6695289

fbshipit-source-id: 913fcfbea4164a02d001bd2344e340c0b6ee62aa

Summary:
[Folly] Let `Futex` import base-class ctors.

Rather than needing to define ctors and inherit `boost::noncopyable`.

Reviewed By: WillerZ

Differential Revision: D6674054

fbshipit-source-id: 59e0a4815682b227346954fe47c6eda49e3ad62f

Summary: Provide capability for custom batching retirement of objects, for example object that belong to the same data structure, to avoid the risk fragmenting related objects across thread local lists of retired objects of many threads, which could lead to unnecessarily high memory usage.

Reviewed By: djwatson

Differential Revision: D6686603

fbshipit-source-id: fadcade73e71170ef1bcec221c4da6f4ddeecff5

Summary: [Folly] Tweak `FutexResult` comments.

Reviewed By: nbronson

Differential Revision: D6673979

fbshipit-source-id: 1777311cd93d5a83432c4ebb48a8432a1c504ca9

Summary: [Folly] `Futex::futexWait` returns `FutexResult`.

Reviewed By: nbronson

Differential Revision: D6673871

fbshipit-source-id: 378c69d8362970e985da31e31d8e9b0179d2917f

Summary:
[Folly] Support for all clock types in `Futex`.

Only `system_clock` and `steady_clock` remain optimal as before, but at least let `Futex` work, even if non-optimally, for all clock types.

Reviewed By: nbronson

Differential Revision: D6673741

fbshipit-source-id: 0a0f778f61b71bea76e12b7fab478e33ce3bbaae

Summary: [Folly] Use ptr-to-`const` in `Futex`.

Reviewed By: igorsugak

Differential Revision: D6673723

fbshipit-source-id: b828c2284b40ec8166e823eca7725beccd330f87

Summary: [Folly] Fix some copyright lines in `folly/detail/` and `folly/test/`.

Differential Revision: D6673878

fbshipit-source-id: 6c060a974bb4d40d0f24a44ebddddf892805c65e

Summary: [Folly] Baton support for wait-options

Reviewed By: nbronson

Differential Revision: D6591168

fbshipit-source-id: beca8422ac0daa572fb43c371923a86f199999f9

Summary:
[Folly] Timed wait operations for spin-only `Baton`.

Enables `try_wait_for` and `try_wait_until` for `Baton</* MayBlock = */ false, /*...*/>`.

Reviewed By: nbronson

Differential Revision: D6672153

fbshipit-source-id: 95da07260b21c2b88b8f7bf81cbfcbe5f5099ac0

Summary:
Update `getXlogCategoryNameForFile()` to keep the file name suffix (e.g., `.h`
or `.cpp`) in the category name.  Previously the code had stripped this out.
However it seems worth leaving it in:
- This makes it possible to independently control log levels for messages from
  the header file vs the cpp file.
- This makes the category name logic slightly easier to explain to users.

The documents I added in D6525997 already describe this new category name
selection behavior.  This change updates the code to match the documented
behavior.

Reviewed By: yfeldblum

Differential Revision: D6690464

fbshipit-source-id: 9af6b549d084bd900f788a08e9213e82579b664a

Summary:
Define INFO0 through INFO9 levels for users that want to have finer-grained
control over info log messages.

This also renumbers the DBG log levels slightly so that there are exactly 1000
levels between each major log level step.  This renumbering change should not
affect any code behavior, since these level values are primarily used in memory
and aren't saved persistently anywhere.

Reviewed By: yfeldblum

Differential Revision: D6690466

fbshipit-source-id: acd499cff6830a1d1b579f295bd4b2bac93b5ada

Summary:
I ran into some open source projects that define `DEBUG` as a preprocessor
macro on the compiler command line.  (They effectively defined it as the
opposite of `NDEBUG`.)  Doing some Google searches revealed that there are a
number of projects that appear to use this as a macro.

Therefore this diff renames the `DEBUG` log level enum value to `DBG` to avoid
potentially conflicting with projects that do use `DEBUG` as a macro name.

I did keep the behavior that `logLevelToString()` returns "DEBUG" for an input
of `LogLevel::DBG`.

Reviewed By: yfeldblum

Differential Revision: D6690465

fbshipit-source-id: 35bb1698afb45eb670e60c192f21390cbf09331d

Summary:
When compiling without optimizations binding the proxy by
reference is slightly faster (no differences in opt mode), so change
the documentation to recommend this syntax.

The proxy can still be bound by `auto`, `const auto`, and `const
auto&`, in all case behaving as expected and with no overhead in opt
mode. Added a test to make sure these all work.

Reviewed By: yfeldblum, luciang

Differential Revision: D6688958

fbshipit-source-id: 7c6b460a01708786bda7614546fa2e1667f27299

Reviewed By: yfeldblum, WillerZ

Differential Revision: D6682606

fbshipit-source-id: 5a203a849e96d3020cf9ad2669451122954c2199

Summary:
title

Created from Diffusion's 'Open in Editor' feature.

(Note: this ignores all push blocking failures!)

Reviewed By: Sushisugre

Differential Revision: D6688367

fbshipit-source-id: 6e2f2d3fcb897fe78c1caef841515856b1f2bd42

Summary: Return if we handle any error messages to avoid unnecessarily calling recv/send

Reviewed By: yfeldblum

Differential Revision: D6677314

fbshipit-source-id: 21f724bb2c92b954888ba97bf7820d72decd2775

Summary: Use new ParkingLot API in futex.

Reviewed By: yfeldblum

Differential Revision: D6595853

fbshipit-source-id: 7024ac1d3e0c5958a651a3e33c1427038bbe7808

Summary:
Batching reference counts reduces the maximum number of atomic_shared_ptrs
available to the system (and also shared_ptrs).

Add a check, test, and some comments about it.

Reviewed By: yfeldblum

Differential Revision: D5916291

fbshipit-source-id: 0bbf7b43284d94a304201219883c82b3654c1585

Summary: Adjust the segment size of the `UnboundedQueue` to 64 instead of 256, a size more suitable for CPUThreadPoolExecutor::CPUTask elements.

Reviewed By: djwatson

Differential Revision: D6665918

fbshipit-source-id: c34c4fa936ee5c6d6a3dd4489129c936369f3980

Summary: This makes sure that whether folly is statically or dynamically linked, all folly exception types will have exactly one definition, and one set of type information.

Reviewed By: mzlee

Differential Revision: D6671431

fbshipit-source-id: 1c06826a05f87cbf9af747c9abdb5f524744d054

Summary: Found that testing would fail on aarch64 since mmx is an Intel thing.  Changed it to just check for x64.

Reviewed By: yfeldblum

Differential Revision: D6670050

fbshipit-source-id: 6ce4b45bb5ef02d65305636d6ac28be7631ddf1b

Summary:
D6617812 wants to build a StringPiece from a literal with an
embedded nul. Add a test to verify that _sp is suitable for this use
case.

Reviewed By: yfeldblum

Differential Revision: D6651024

fbshipit-source-id: be4fb875762829fdb61c57fa72954fef286e9df0

Summary: ERR_error_string will use a static buffer if none is provided.  This is unsafe in threaded envs when we build a string out of it later.  Switch this to use ERR_error_string_n

Reviewed By: yfeldblum, knekritz

Differential Revision: D6664958

fbshipit-source-id: 2071347373ac61ebc28296fa66845cd718172b5e

Summary:
[Folly] Remove gcc-v4.7 support from `MemoryIdler`.

As of gcc-v4.8, `std::is_trivial<std::chrono::duration<Rep, Period>>::value` holds. We no longer need any extra support.

Reviewed By: meyering

Differential Revision: D6673517

fbshipit-source-id: f28b2d126f113547ebf36c85f9fa37a5d944d65b

Summary: [Folly] Terminal comma for `FutexResult` enumerators. Style nit.

Reviewed By: meyering

Differential Revision: D6673523

fbshipit-source-id: abf9f4d3e99bf9a6d3042a49252b1b1190e69b9f

Summary: Use `auto` for scope-guard locals v.s. `folly::ScopeGuard`.

Reviewed By: igorsugak, meyering

Differential Revision: D6664915

fbshipit-source-id: ea239b712f3f9dc7ef81105aaf82f4b36bc07db5

Summary: Default constructors are strange and often unexpected. Refactor.

Reviewed By: yfeldblum

Differential Revision: D6667480

fbshipit-source-id: 24c456c46c846c61e28f1a88806d7c36d9192493

Summary: Change the threshold for pushing privately held retired object to the domain to a moderate constant instead of using the threshold for bulk reclamation which is too high for this purpose.

Reviewed By: djwatson

Differential Revision: D6665904

fbshipit-source-id: 0b090884843b0296a93af7994f7183f41c00000e

Summary:
[Folly] `Synchronized::exchange`, for assigning a new value and returning the old value.

(Note: this ignores all push blocking failures!)

Differential Revision: D6653482

fbshipit-source-id: 68f4bd330bc2cf37bb92aff98b8ce3221334112e

Summary: [Folly] Fix copyright lines in `folly/synchronization/Baton.h`.

Reviewed By: meyering

Differential Revision: D6665595

fbshipit-source-id: 84aa0c475f01c858d543a047103437c083b3a4ed

Summary: Adds wording indicating that it is safe to call this function multiple times.

Reviewed By: yfeldblum

Differential Revision: D6625530

fbshipit-source-id: 2305f7b8e3451a6663003d23230b22c6f65a3729

Summary: [Folly] Cut `glog` include from `folly/synchronization/RWSpinLock.h`.

Reviewed By: meyering

Differential Revision: D6659300

fbshipit-source-id: 0f1b79d98be0656694f57667252a16acd54e2414