Commit 6b34350f authored by Tom Zanussi's avatar Tom Zanussi Committed by Linus Torvalds
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[PATCH] relayfs: Documentation cleanup, remove obsolete info



librelay and relay-app.h have been retired - update Documentation to reflect
that.
Signed-off-by: default avatarTom Zanussi <zanussi@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 761da5c8
...@@ -44,30 +44,41 @@ relayfs can operate in a mode where it will overwrite data not yet ...@@ -44,30 +44,41 @@ relayfs can operate in a mode where it will overwrite data not yet
collected by userspace, and not wait for it to consume it. collected by userspace, and not wait for it to consume it.
relayfs itself does not provide for communication of such data between relayfs itself does not provide for communication of such data between
userspace and kernel, allowing the kernel side to remain simple and not userspace and kernel, allowing the kernel side to remain simple and
impose a single interface on userspace. It does provide a separate not impose a single interface on userspace. It does provide a set of
helper though, described below. examples and a separate helper though, described below.
klog and relay-apps example code
================================
relayfs itself is ready to use, but to make things easier, a couple
simple utility functions and a set of examples are provided.
The relay-apps example tarball, available on the relayfs sourceforge
site, contains a set of self-contained examples, each consisting of a
pair of .c files containing boilerplate code for each of the user and
kernel sides of a relayfs application; combined these two sets of
boilerplate code provide glue to easily stream data to disk, without
having to bother with mundane housekeeping chores.
The 'klog debugging functions' patch (klog.patch in the relay-apps
tarball) provides a couple of high-level logging functions to the
kernel which allow writing formatted text or raw data to a channel,
regardless of whether a channel to write into exists or not, or
whether relayfs is compiled into the kernel or is configured as a
module. These functions allow you to put unconditional 'trace'
statements anywhere in the kernel or kernel modules; only when there
is a 'klog handler' registered will data actually be logged (see the
klog and kleak examples for details).
It is of course possible to use relayfs from scratch i.e. without
using any of the relay-apps example code or klog, but you'll have to
implement communication between userspace and kernel, allowing both to
convey the state of buffers (full, empty, amount of padding).
klog and the relay-apps examples can be found in the relay-apps
tarball on http://relayfs.sourceforge.net
klog, relay-app & librelay
==========================
relayfs itself is ready to use, but to make things easier, two
additional systems are provided. klog is a simple wrapper to make
writing formatted text or raw data to a channel simpler, regardless of
whether a channel to write into exists or not, or whether relayfs is
compiled into the kernel or is configured as a module. relay-app is
the kernel counterpart of userspace librelay.c, combined these two
files provide glue to easily stream data to disk, without having to
bother with housekeeping. klog and relay-app can be used together,
with klog providing high-level logging functions to the kernel and
relay-app taking care of kernel-user control and disk-logging chores.
It is possible to use relayfs without relay-app & librelay, but you'll
have to implement communication between userspace and kernel, allowing
both to convey the state of buffers (full, empty, amount of padding).
klog, relay-app and librelay can be found in the relay-apps tarball on
http://relayfs.sourceforge.net
The relayfs user space API The relayfs user space API
========================== ==========================
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