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vault backup: 2025-04-06 16:58:00

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Marco Realacci 2025-04-06 16:58:00 +02:00
parent 6e87cd5b03
commit 09d45ed1c5
2 changed files with 4 additions and 5 deletions
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6
.obsidian/workspace.json vendored
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@ -13,12 +13,12 @@
"state": {
"type": "markdown",
"state": {
"file": "Concurrent Systems/notes/4 - Semaphores.md",
"file": "Concurrent Systems/notes/4b - Monitors.md",
"mode": "source",
"source": false
},
"icon": "lucide-file",
"title": "4 - Semaphores"
"title": "4b - Monitors"
}
}
]
@ -191,13 +191,13 @@
},
"active": "6550032d28b9171c",
"lastOpenFiles": [
"Concurrent Systems/notes/4 - Semaphores.md",
"Concurrent Systems/notes/3b - Aravind's algorithm and improvements.md",
"Concurrent Systems/notes/10 - Implementing Consensus.md",
"Concurrent Systems/notes/1b - Peterson algorithm.md",
"Concurrent Systems/slides/class 5.pdf",
"Concurrent Systems/notes/5 - Software Transactional Memory.md",
"Concurrent Systems/notes/4c - Dining Philosophers.md",
"Concurrent Systems/notes/4 - Semaphores.md",
"\u0002.md",
"Concurrent Systems/notes/2b - Round Robin algorithm.md",
"\u0001.md",

3
Concurrent Systems/notes/4 - Semaphores.md
View file

@ -299,5 +299,4 @@ def end_write() :=
W_MUTEX.up()
return
```
This is prioritizing writers as if there are writers waiting, they will be waiting at `GLOB_MUTEX.down()`. This semaphore is upped before `PRIO_MUTEX` which is the one that blocks readers.
But writers won't be able to writer until there are no readers, if they keep coming, they will block the writers as `GLOB_MUTEX` will never be upped.
This is prioritizing writers as if there are writers waiting, they will be waiting at `GLOB_MUTEX.down()`. This semaphore is upped before `PRIO_MUTEX` which is the one that blocks readers.