Commit 5da98b82 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Jonathan Corbet
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pi-futex.txt: standardize document format

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx.

This document requires just minor adjustments to match
the standard documentation style:

- promote document name;
- remove extra collons on some chapter titles;
- use "-" for a bulleted list.
Signed-off-by: default avatarMauro Carvalho Chehab <>
Signed-off-by: default avatarJonathan Corbet <>
parent 5426a2cc
Lightweight PI-futexes
We are calling them lightweight for 3 reasons:
......@@ -25,8 +26,8 @@ determinism and well-bound latencies. Even in the worst-case, PI will
improve the statistical distribution of locking related application
The longer reply:
The longer reply
Firstly, sharing locks between multiple tasks is a common programming
technique that often cannot be replaced with lockless algorithms. As we
......@@ -71,8 +72,8 @@ deterministic execution of the high-prio task: any medium-priority task
could preempt the low-prio task while it holds the shared lock and
executes the critical section, and could delay it indefinitely.
As mentioned before, the userspace fastpath of PI-enabled pthread
mutexes involves no kernel work at all - they behave quite similarly to
......@@ -83,8 +84,8 @@ entering the kernel.
To handle the slowpath, we have added two new futex ops:
If the lock-acquire fastpath fails, [i.e. an atomic transition from 0 to
TID fails], then FUTEX_LOCK_PI is called. The kernel does all the
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