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Change-Id: I1f4517e1952d5b82ce679ebd2544b7403b1d37d8 Signed-off-by: Krishnan Parthasarathi <kparthas@redhat.com> Reviewed-on: https://review.gluster.org/10365 Tested-by: NetBSD Build System <jenkins@build.gluster.org> Tested-by: Raghavendra G <rgowdapp@redhat.com> CentOS-regression: Gluster Build System <jenkins@build.gluster.org> Smoke: Gluster Build System <jenkins@build.gluster.org> Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
2.6 KiB
#syncop framework A coroutines-based, cooperative multi-tasking framework.
Topics
- Glossary
- Lifecycle of a synctask
- Existing usage
Glossary
syncenv
syncenv is an object that provides access to a pool of worker threads. synctasks execute in a syncenv.
synctask
synctask can be informally defined as a pair of function pointers, namely the call and the callback (see syncop.h for more details).
synctask_fn_t - 'the call'
synctask_cbk_t - 'the callback'
synctask has two modes of operation,
- The calling thread waits for the synctask to complete.
- The calling thread schedules the synctask and continues.
synctask guarantees that the callback is called after the call completes.
Lifecycle of a synctask
A synctask could go into the following stages while in execution.
-
CREATED - On calling synctask_create/synctask_new.
-
RUNNABLE - synctask is queued in env->runq.
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RUNNING - When one of syncenv's worker threads calls synctask_switch_to.
-
WAITING - When a synctask calls synctask_yield.
-
DONE - When a synctask has run to completion.
+-------------------------------+ | CREATED | +-------------------------------+ | | synctask_new/synctask_create v +-------------------------------+ | RUNNABLE (in env->runq) | <+ +-------------------------------+ | | | | synctask_switch_to | v |
+------+ on task completion +-------------------------------+ | | DONE | <-------------------- | RUNNING | | synctask_wake/wake +------+ +-------------------------------+ | | | | synctask_yield/yield | v | +-------------------------------+ | | WAITING (in env->waitq) | -+ +-------------------------------+
Note: A synctask is not guaranteed to run on the same thread throughout its lifetime. Every time a synctask yields, it is possible for it to run on a different thread.