Commit b09ae853 authored by Mike Gerdts's avatar Mike Gerdts Committed by Tomasz Zawadzki
Browse files

doc: mention SPDK spinlocks in concurrency.md 



Encourage the use of spdk_spinlock over pthread_mutex_t and
pthread_spinlock_t to improve safety and debugability.

Signed-off-by: default avatarMike Gerdts <mgerdts@nvidia.com>
Change-Id: I22e2d3cc917687c9878d7558fe8c640051b51a45
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/16021


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
parent ed4b89aa

doc/concurrency.md

+12 −0
Original line number Diff line number Diff line
@@ -110,6 +110,18 @@ repeatedly call `spdk_thread_poll()` on each `spdk_thread()` that exists. This 
makes SPDK very portable to a wide variety of asynchronous, event-based

frameworks such as [Seastar](https://www.seastar.io) or [libuv](https://libuv.org/).



## SPDK Spinlocks



There are some cases where locks are used. These should be limited in favor of

the message passing interface described above. When locks are needed,

SPDK spinlocks should be used instead of POSIX locks.



POSIX locks like `pthread_mutex_t` and `pthread_spinlock_t` do not properly

handle locking between SPDK's lightweight threads. SPDK's `spdk_spinlock`

is safe to use in SPDK libraries and applications. This safety comes from

imposing restrictions on when locks can be held. See

[spdk_spinlock](structspdk__spinlock.html) for details.



## The event Framework



The SPDK project didn't want to officially pick an asynchronous, event-based