Summary:
Two ordering issues:

setTreeNode cannot store the node as relaxed, because the node is newly allocated before storing, and if another thread gets the node pointer value, relaxed ordering cannot guarantee that the node has been fully initialized before it.

There are two ways this node can be read, one via optimisticReadValue, which loads with memory_order_acquired, which would now correctly synchronize with the release; the other is readValue, which I think was intended to be used only when the lock corresponding to the node is held, but there is one case on line 781 in forceInsert where we fail to acquire the lock but it looks like we want to retry unless we're out of capacity (on a best effort basis) and therefore we call readValue to check the capacity (on a best effort basis), so it looks as if memory_order_relaxed is okay, but it is not, because the node is a pointer that may not be fully initialized with relaxed ordering. So I'm changing that to memory_order_acquire as well.

In general it's not really valid to use relaxed ordering if the value is a pointer and the pointee is allocated on the fly.

Reviewed By: yfeldblum

Differential Revision: D22936002

fbshipit-source-id: 1c8a000b6033e4a81df5f9a5e850cfe350dbeb15

Summary: Remove TSAN code that caused an assert

Reviewed By: andriigrynenko

Differential Revision: D22925613

fbshipit-source-id: 67cf634ccd29453a6e399951b8bf541a2c471104

Summary:
The SymbolizePrinter classes are portable to any unix, so split them
into their own target.

Reviewed By: yfeldblum, luciang

Differential Revision: D22883912

fbshipit-source-id: 3bce6d6584182b818bf803da187eae56477bac8a

Summary:
In the interest of using SignalHandler on macOS, which does not use
ELF, break some dependencies and split the targets.

Reviewed By: yfeldblum, luciang

Differential Revision: D22883896

fbshipit-source-id: e576b6e1684522fc1665c864780faea882d0263a

Summary: The memory ordering when loading the `waiter_` atomic must be at least memory_order_acquire to ensure that anything sequenced after timedWaitThread happens before the corresponding post call. In fact, this is already the memory ordering used in the non-timed version Baton::waitThread.

Differential Revision: D22901656

fbshipit-source-id: 8e8156bdfda02d6b26565b91054ef3cc59a28e8a

Summary: Add support for TimerFD async recv

Reviewed By: kevin-vigor

Differential Revision: D22860507

fbshipit-source-id: e1afc9d72608f5a574413e1230d6665420240af7

Summary: Add APIs to disable rx/tx checksum for UDP over IPV6

Differential Revision: D22487077

fbshipit-source-id: 22af21b108e84782ec0a76ccbc49eaafa73bd266

Summary: Mcrouter has a logger thread which queries the fiber manager for 3 stats; these stats are non-atomic and therefore this causes a race. This diff applies a simple fix to make these atomic. It does not feel like this is the best fix though, so let me know if anyone has ideas for a better fix. It feels that stats should be provided some other way (rather than a bunch of atomics)...

Reviewed By: yfeldblum

Differential Revision: D22878457

fbshipit-source-id: f17544b38836c454162b83cfa570c90c5e7e6b9a

Summary:
port serdes object type is introduced in 1.5.2

upgrading tp2 sai dependency to 1.5.2

note that for first time, oss build failed, i had to back out removing http_proxy and https_proxy indicated here - D17429928

Differential Revision: D22888202

fbshipit-source-id: c0f90b1caa01603d25b0559188ae961df1dd13d5

Summary: TSAN has a limit of 8128 threads.

Reviewed By: yfeldblum

Differential Revision: D22888242

fbshipit-source-id: 12b78e11145de433dfa31ea1480649af7f8dac57

Summary: Simplify the interface as the touch(), remove() methods are not needed now.

Reviewed By: therealgymmy

Differential Revision: D22547658

fbshipit-source-id: 6d5c799fb21cb4cb6ee20203c820f4d6ff7e8255

Summary: Like ASAN, TSAN also maps large memory regions. So disable the rlimit for TSAN as well.

Differential Revision: D22743326

fbshipit-source-id: 5023b66f1526894c77e6c693a2481f6ade388b9e

Summary: [Folly] Avoid `std::forward` in `folly/futures/` since function template instantiation is expensive at compile time and `std::forward` is, when used correctly, nothing more than library sugar for straightforward syntax.

Reviewed By: LeeHowes

Differential Revision: D22673234

fbshipit-source-id: f88bc8c8aa13797ae6eccf1a421a47ff135589e1

Summary:
Some of the CHECKs and DCHECKs in F14 are often tripped by users
that write to an F14 map or set from multiple threads without proper
concurrency control.  This diff adds a message to those locations that
suggests that they may have a race condition.

Reviewed By: yfeldblum

Differential Revision: D22826369

fbshipit-source-id: 8d5e96feea4dbb8dda404980d9a9d3412fb2eb64

Summary:
See task T70610458 description for the TSAN error reported.

The scenario that can trigger this race condition is:
 * Thread A has a ThreadEntryNode N whose `next` points to thread B's ThreadEntry.
 * Thread B exits, which causes it to delete its ThreadEntry and all its nodes; therefore writing `N->next = <the next entry after B>`.
 * At the same time, thread A accesses the thread local corresponding to N; when checking whether the ThreadEntryNode is already added to the linked list, it checks whether the `next` pointer is null; this read races with the above write.

Even though this is a technically a race condition, it is unlikely to actually trigger any negative effect in practice, because at thread exit, the overwrite of `N->next = ...` will never assign a nullptr, so it will never affect the outcome of `if (!next)` in thread A. Only the thread that owns the ThreadEntryNode has the ability to change between `next == nullptr` and `next != nullptr`. (The former is called "zero" in the code). Nonetheless, C++ says "race condition leads to undefined behavior", so it's still good to fix...

It's not clear what the best way to fix this is. Here I've presented one fix, which is to introduce another field in ThreadEntryNode that is private to the thread and simply indicates whether the node is zero; this field is strictly accessed by only the owning thread and therefore will not cause a race condition. I used a bit in `id` to not increase memory consumption, but maybe that's not important - I don't know. I'm also unsure about the performance implications.

Let me know if anyone has different ideas; I'm very open to suggestions here.

Reviewed By: yfeldblum

Differential Revision: D22743031

fbshipit-source-id: 12722ca241a224b546a0f6763b125e922813c844

Summary: Turned it into a thread_local instead. Only affects tests.

Reviewed By: yfeldblum

Differential Revision: D22744469

fbshipit-source-id: cbe8263d560f5abad27c7e61b1963aecf090a94e

Summary:
See RefCountTest.cpp for a newly added test. When one thread is decrementing a local refcount and another thread is decrementing a global refcount, and the global decrement results in global zero, the second thread can reasonably expect to be able to safely destroy the refcount object. However, a memory ordering issue in LocalRefCount::collect() causes TSAN to detect a write-delete race condition on the inUpdate_ variable (though that variable is not the cause of the issue).

This diff changes collect() to use memory_order_acquire so that upon reading false, collect() may exit while assuming that all memory accesses in update() are complete. This way, any memory accesses (such as a read of refCount_.state_ in update()) happen before a delete of the whole TLRefCount like so:

 - A memory access in update() is sequenced before the release store of false into inUpdate_ at the SCOPE_EXIT of the function,
 - which synchronizes with the acquire load at the end of collect()
 - which is sequenced before the deletion that can only happen after collect()

Without this diff, the second relationship above is broken and TSAN complains.

I also updated the comment on top of inUpdate_ to better reflect the purpose. I couldn't understand the original comment (which seems to suggest it's related to refcount *correctness* rather than a write-delete race), but maybe I missed something there.

Reviewed By: yfeldblum

Differential Revision: D22805717

fbshipit-source-id: 34cf72676760526ba457f939e307ed03dc722528

Summary:
we do have some periodic maintentenance tasks... if those are initialized
lazily on a requests handling path, they  will capture current rctx and keep it
it alive forever.

Reviewed By: yfeldblum

Differential Revision: D22859344

fbshipit-source-id: 3655d874dee22aaf74b4d80631d4a58e83539752

Summary: AppBytesWitten was no longer updated correctly for AsyncSSLSocket, fix this.

Reviewed By: bschlinker

Differential Revision: D22847139

fbshipit-source-id: 8cabb9883e5ad64c49a283a0d83b8087def4d5ae

Summary:
Currently when context string is "", we will still append whitespace to log header. This looks like:
```
I0729 17:36:53.249270 438847 ThriftServerEventHandler.cpp:21 ] Sampling servers
```
which is less readable compared to
```
I0729 17:36:53.249270 438847 ThriftServerEventHandler.cpp:21] Sampling servers
```
. Ideally empty context string should mean "there's no context string to report here", so we should not put an extra delimiter in such case.

Reviewed By: simpkins

Differential Revision: D22835634

fbshipit-source-id: c7fc6de4036050eac3b7d16bf607c637d1394c44

Reviewed By: yfeldblum

Differential Revision: D22843001

fbshipit-source-id: 55f48de90f16c53983ea94c8e1102c5b33e25195

Summary:
I'm using AsyncPipe heavily in D22593723. At one iteration I needed to assign with move a holding object and it wouldn't compile because the operator doesn't return any value

Here's the error: `folly/experimental/coro/AsyncPipe.h:54:3: error: control reaches end of non-void function [-Werror,-Wreturn-type]`

Reviewed By: yfeldblum

Differential Revision: D22593724

fbshipit-source-id: 53f27b95c1dff0068a375291d4ee6f445f892dd9

Summary: [Folly] Move an `exception_ptr` in `exceptionStr`, which should be ever-so-slightly cheaper than copying it since that may avoid atomic refcount operations. It's not much cheaper overall because the throw/catch machinery remains expensive.

Reviewed By: ot, luciang

Differential Revision: D22529858

fbshipit-source-id: 7e5d4ec5c1ca601a766c63133ae759651ae7be85

Summary: [Folly] Outline `exceptionStr` function bodies and move them to the `.cpp`.

Reviewed By: ot, luciang

Differential Revision: D22529702

fbshipit-source-id: 165c14009f224e86e63b3a3126c8b837cf3793f5

Summary: [Folly] Skip the safe-assert dep on FileUtil since it really needs only the combinators.

Reviewed By: Orvid

Differential Revision: D22699899

fbshipit-source-id: 73485439e397c10210d09eacbb38116e3e0a50a0

Summary:
F14MapFallback.h and F14SetFallback.h can now be compiled
standalone when F14 intrinsics are disabled.

Reviewed By: andrewjcg, yfeldblum

Differential Revision: D22785153

fbshipit-source-id: 96a1d3b2773a83dee8484fa40f35bbc791aec57c

Summary: [Folly] Drop support for boost below 1.61, which means removing multiple versions of support for `boost-context` embedded in `folly/fibers/`.

Reviewed By: fredemmott

Differential Revision: D22779795

fbshipit-source-id: fafc9b38784dcb206283e11d01d77dd8655354a6

Summary: [Folly] Tweak safe-assert uses of wrapper functions.

Reviewed By: nbronson

Differential Revision: D22699636

fbshipit-source-id: 97592e55f64f2e819680424c0f1ddd97e1f7b96c

Summary: adding CANCELED to AsyncSocketExceptionType

Reviewed By: yfeldblum

Differential Revision: D22345735

fbshipit-source-id: 73c61b409531d71a39d82a46d9c0ebc720801c45

Summary:
Adding a new method `ConcurrentHashMap::erase_key_if`. This is a more general form of `erase_if_equal`, which allows arbitrary predicates to be evaluated against the existing value type, rather than simple equality.

`erase_key_if` was chosen as a name to avoid confusion with `std::erase_if`.

Reviewed By: magedm

Differential Revision: D22775217

fbshipit-source-id: 151975216d5d4288ec4e88b81f6a8d17a091e8f0

Summary:
- I find the ability to make a branch and play with CI on GitHub super handy
- Removing the `- master` limitation gives me this ability

Reviewed By: yi-xian

Differential Revision: D22771835

fbshipit-source-id: 8e8839cb860ab4d1dfa0dda590afaf165127f60d

Summary: Fix 1-byte buffer overrun when parsing the string "-".

Reviewed By: mhlakhani

Differential Revision: D22695995

fbshipit-source-id: 9d1834c068fc3889a514b77d53d626eb6f72b6c6

Summary: In addition to `folly::fibers::Semaphore` which only accepts single token increment/decrement. `folly::fibers::BatchSemaphore` is able to accept batch tokens

Differential Revision: D21874795

fbshipit-source-id: 1d4c62bdb079c058529cd917078d81d09d585084

Summary:
* Implement `SemaphoreBase` which is able to accept batch tokens, most of the logic is copy-pasted from `folly::fibers::Semaphore` with batch token as parameter
* This serves as base object which is not public accesseble
* BatchSemaphore which is able to accept batch tokens and Semaphore will use `SemaphoreBase` as a fundation

Differential Revision: D21874699

fbshipit-source-id: 2536284a2480f2972bd00010833de49bcd5304b2

Summary:
- Replace deprecated method
- Stops spam to my console as I run with show deprecation warnings

Reviewed By: yi-xian

Differential Revision: D22776372

fbshipit-source-id: d29193e4c4c26d7facfabf9038dcb33c1af92434

Summary:
MSVC's maintains an intrusive linked list of iterators for
debugging purposes in some build configurations, which means that
F14MapFallback's hacky conversion from unordered_map::local_iterator to
unordered_map::iterator doesn't work.  Fortunately, on that platform
local_iterator and iterator are the same type, so no hack is needed.

Reviewed By: Orvid

Differential Revision: D22776318

fbshipit-source-id: 80283c4c451afffe522e55e47cd94971126a6fa6

Summary: we should report the name of the executore/threadpool that is saturated. propagate names of the executor/threadpool onto the queue we are monitoring.

Reviewed By: andriigrynenko

Differential Revision: D20773871

fbshipit-source-id: f7f78edd62d515cca19e30a63773180404843c1b

Summary:
as titled

The issue here was that we were clearing out the value of current rctx from TLS, then calling `onUnset`. So calling `RequestContext::get` from within the `onUnset` callback resulted in returning the default global RCTX.

Reviewed By: yfeldblum, zhxchen17

Differential Revision: D22750092

fbshipit-source-id: 509676d047cf6aec05d08ff3bf656d6d1558fbf5

Summary:
- Make OpenR build all deps from source until we remove fbzmq as a dep
- Allow a project to move it's Open Source CI forward to an alternative version of ubuntu via a new `--ubuntu-version` parameter

Reviewed By: wez

Differential Revision: D22768987

fbshipit-source-id: 07205efbd0c87a702638cf30b84a2850d064fa8e

Reviewed By: andrewjcg

Differential Revision: D22743063

fbshipit-source-id: 1da870027c92b11509056769626ed1f442d1b426