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| author | Laurent Bercot <ska-skaware@skarnet.org> | 2014-12-05 22:26:11 +0000 |
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| committer | Laurent Bercot <ska-skaware@skarnet.org> | 2014-12-05 22:26:11 +0000 |
| commit | 90b12bd71bb9fc79a4640b9112c13ef529d0196a (patch) | |
| tree | 523b3f4ee2969e7a729bab2ba749c4b924ae62af /doc/libs6lock/s6lockd-helper.html | |
| download | s6-90b12bd71bb9fc79a4640b9112c13ef529d0196a.tar.xz | |
Initial commit
Diffstat (limited to 'doc/libs6lock/s6lockd-helper.html')
| -rw-r--r-- | doc/libs6lock/s6lockd-helper.html | 52 |
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diff --git a/doc/libs6lock/s6lockd-helper.html b/doc/libs6lock/s6lockd-helper.html new file mode 100644 index 0000000..839dce4 --- /dev/null +++ b/doc/libs6lock/s6lockd-helper.html @@ -0,0 +1,52 @@ +<html> + <head> + <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> + <meta http-equiv="Content-Language" content="en" /> + <title>s6: the s6lockd-helper internal program</title> + <meta name="Description" content="s6: the s6lockd-helper internal program" /> + <meta name="Keywords" content="s6 s6lockd-helper lockd asynchronous timed lock daemon helper" /> + <!-- <link rel="stylesheet" type="text/css" href="http://skarnet.org/default.css" /> --> + </head> +<body> + +<a href="index.html">libs6lock</a><br /> +<a href="../">s6</a><br /> +<a href="http://skarnet.org/software/">Software</a><br /> +<a href="http://skarnet.org/">skarnet.org</a><p /> + +<h1> The <tt>s6lockd-helper</tt> program </h1> + +<p> +<tt>s6lockd-helper</tt> is a helper program for the s6lock daemon. +It just acquires a lock and holds it until it is killed or told to +exit by its parent daemon. +</p> + +<h2> Interface </h2> + +<p> + s6lockd-helper is not meant to be invoked directly by the user: +it will be spawned by the +<a href="s6lockd.html">s6lockd</a> program. +</p> + +<h2> Notes </h2> + +<ul> + <li> s6lockd-helper blocks on lock acquisition until it succeeds. It then +notifies its parent. It exits when its parent tells him to (i.e. when the +client asks for lock release). During the lock acquisition phase, it can +be killed if its parent detects a timeout. </li> + <li> One s6lockd-helper process per lock is the only way (apart from +threads) to implement timed lock acquisition. This can lead to a lot of +s6lockd-helper processes, but this is not a problem: + <ul> + <li> Processes are not a scarce resource. Today's schedulers work in O(1), +i.e. a sleeping process takes no scheduling time at all. </li> + <li> s6lockd-helper is extremely tiny. Every instance should use up at +most one or two pages of non-sharable memory. </li> + </ul> </li> +</ul> + +</body> +</html> |