aboutsummaryrefslogtreecommitdiff
path: root/src/include/storage/condition_variable.h
Commit message (Collapse)AuthorAge
* Replace buffer I/O locks with condition variables.Thomas Munro2021-03-11
| | | | | | | | | | | | | | | | | | | 1. Backends waiting for buffer I/O are now interruptible. 2. If something goes wrong in a backend that is currently performing I/O, waiting backends no longer wake up until that backend reaches AbortBufferIO() and broadcasts on the CV. Previously, any waiters would wake up (because the I/O lock was automatically released) and then busy-loop until AbortBufferIO() cleared BM_IO_IN_PROGRESS. 3. LWLockMinimallyPadded is removed, as it would now be unused. Author: Robert Haas <robertmhaas@gmail.com> Reviewed-by: Thomas Munro <thomas.munro@gmail.com> Reviewed-by: Julien Rouhaud <rjuju123@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (earlier version, 2016) Discussion: https://postgr.es/m/CA%2BhUKGJ8nBFrjLuCTuqKN0pd2PQOwj9b_jnsiGFFMDvUxahj_A%40mail.gmail.com Discussion: https://postgr.es/m/CA+Tgmoaj2aPti0yho7FeEf2qt-JgQPRWb0gci_o1Hfr=C56Xng@mail.gmail.com
* Update copyright for 2021Bruce Momjian2021-01-02
| | | | Backpatch-through: 9.5
* Clean up includes of s_lock.h.Andres Freund2020-06-18
| | | | | | | Users of spinlocks should use spin.h, not s_lock.h. And lwlock.h hasn't utilized spinlocks for quite a while. Discussion: https://postgr.es/m/20200618183041.upyrd25eosecyf3x@alap3.anarazel.de
* Spelling adjustmentsPeter Eisentraut2020-06-07
|
* Update copyrights for 2020Bruce Momjian2020-01-01
| | | | Backpatch-through: update all files in master, backpatch legal files through 9.4
* Make the order of the header file includes consistent.Amit Kapila2019-11-25
| | | | | | | | | Similar to commits 14aec03502, 7e735035f2 and dddf4cdc33, this commit makes the order of header file inclusion consistent in more places. Author: Vignesh C Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/CALDaNm2Sznv8RR6Ex-iJO6xAdsxgWhCoETkaYX=+9DW3q0QCfA@mail.gmail.com
* Introduce timed waits for condition variables.Thomas Munro2019-07-13
| | | | | | | | | Provide ConditionVariableTimedSleep(), like ConditionVariableSleep() but with a timeout argument. Author: Shawn Debnath Reviewed-by: Kyotaro Horiguchi, Thomas Munro Discussion: https://postgr.es/m/eeb06007ccfe46e399df6af18bfcd15a@EX13D05UWC002.ant.amazon.com
* Update copyright for 2019Bruce Momjian2019-01-02
| | | | Backpatch-through: certain files through 9.4
* Allow ConditionVariable[PrepareTo]Sleep to auto-switch between CVs.Tom Lane2018-01-09
| | | | | | | | | | | | | | | | | | | | | | | | | | The original coding here insisted that callers manually cancel any prepared sleep for one condition variable before starting a sleep on another one. While that's not a huge burden today, it seems like a gotcha that will bite us in future if the use of condition variables increases; anything we can do to make the use of this API simpler and more robust is attractive. Hence, allow these functions to automatically switch their attention to a different CV when required. This is safe for the same reason it was OK for commit aced5a92b to let a broadcast operation cancel any prepared CV sleep: whenever we return to the other test-and-sleep loop, we will automatically re-prepare that CV, paying at most an extra test of that loop's exit condition. Back-patch to v10 where condition variables were introduced. Ordinarily we would probably not back-patch a change like this, but since it does not invalidate any coding pattern that was legal before, it seems safe enough. Furthermore, there's an open bug in replorigin_drop() for which the simplest fix requires this. Even if we chose to fix that in some more complicated way, the hazard would remain that we might back-patch some other bug fix that requires this behavior. Patch by me, reviewed by Thomas Munro. Discussion: https://postgr.es/m/2437.1515368316@sss.pgh.pa.us
* Cosmetic improvements in condition_variable.[hc].Tom Lane2018-01-08
| | | | | | Clarify a bunch of comments. Discussion: https://postgr.es/m/CAEepm=0NWKehYw7NDoUSf8juuKOPRnCyY3vuaSvhrEWsOTAa3w@mail.gmail.com
* Remove return values of ConditionVariableSignal/Broadcast.Tom Lane2018-01-05
| | | | | | | | | | | | | | | | | | | | | | In the wake of commit aced5a92b, the semantics of these results are a bit squishy: we can tell whether we signaled some other process(es), but we do not know which ones were real waiters versus mere sentinels for ConditionVariableBroadcast operations. It does not help much that ConditionVariableBroadcast will attempt to pass on the signal to the next real waiter, because (a) there might not be one, and (b) that will only happen awhile later, anyway. So these results could overstate how much effect the calls really had. However, no existing caller of either function pays any attention to its result value, so it seems reasonable to just define that as a required property of a correct algorithm. To encourage correctness and save some tiny number of cycles, change both functions to return void. Patch by me, per an observation by Thomas Munro. No back-patch, since if any third parties happen to be using these functions, they might not appreciate an API break in a minor release. Discussion: https://postgr.es/m/CAEepm=0NWKehYw7NDoUSf8juuKOPRnCyY3vuaSvhrEWsOTAa3w@mail.gmail.com
* Update copyright for 2018Bruce Momjian2018-01-02
| | | | Backpatch-through: certain files through 9.3
* Phase 2 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Post-PG 10 beta1 pgindent runBruce Momjian2017-05-17
| | | | perltidy run not included.
* Update copyright via script for 2017Bruce Momjian2017-01-03
|
* Support condition variables.Robert Haas2016-11-22
Condition variables provide a flexible way to sleep until a cooperating process causes an arbitrary condition to become true. In simple cases, this can be accomplished with a WaitLatch/ResetLatch loop; the cooperating process can call SetLatch after performing work that might cause the condition to be satisfied, and the waiting process can recheck the condition each time. However, if the process performing the work doesn't have an easy way to identify which processes might be waiting, this doesn't work, because it can't identify which latches to set. Condition variables solve that problem by internally maintaining a list of waiters; a process that may have caused some waiter's condition to be satisfied must "signal" or "broadcast" on the condition variable. Robert Haas and Thomas Munro