From 4d2e7d0d77e4e1e8a21cc990c607985fdba20e66 Mon Sep 17 00:00:00 2001 From: Matti Linnanvuori Date: Tue, 13 May 2008 18:31:47 +0300 Subject: doc: add a chapter about trylock functions [Bug 9011] Add a chapter about trylock functions. http://bugzilla.kernel.org/show_bug.cgi?id=9011 Signed-off-by: Matti Linnanvuori Signed-off-by: Rusty Russell (removed down_trylock) --- Documentation/DocBook/kernel-locking.tmpl | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'Documentation/DocBook') diff --git a/Documentation/DocBook/kernel-locking.tmpl b/Documentation/DocBook/kernel-locking.tmpl index 77c42f40be5d..2510763295d0 100644 --- a/Documentation/DocBook/kernel-locking.tmpl +++ b/Documentation/DocBook/kernel-locking.tmpl @@ -703,6 +703,31 @@ + + The trylock Functions + + There are functions that try to acquire a lock only once and immediately + return a value telling about success or failure to acquire the lock. + They can be used if you need no access to the data protected with the lock + when some other thread is holding the lock. You should acquire the lock + later if you then need access to the data protected with the lock. + + + + spin_trylock() does not spin but returns non-zero if + it acquires the spinlock on the first try or 0 if not. This function can + be used in all contexts like spin_lock: you must have + disabled the contexts that might interrupt you and acquire the spin lock. + + + + mutex_trylock() does not suspend your task + but returns non-zero if it could lock the mutex on the first try + or 0 if not. This function cannot be safely used in hardware or software + interrupt contexts despite not sleeping. + + + Common Examples -- cgit v1.2.3 From a606b5e24b7e2937604f4c85023d8d9c5ab0a28b Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Tue, 24 Jun 2008 10:52:55 -0500 Subject: kgdb: documentation update - remove kgdboe kgdboe is not presently included kgdb, and there should be no references to it. Also fix the tcp port terminal connection example. Signed-off-by: Jason Wessel --- Documentation/DocBook/kgdb.tmpl | 20 ++++++-------------- 1 file changed, 6 insertions(+), 14 deletions(-) (limited to 'Documentation/DocBook') diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl index 028a8444d95e..e8acd1f03456 100644 --- a/Documentation/DocBook/kgdb.tmpl +++ b/Documentation/DocBook/kgdb.tmpl @@ -84,10 +84,9 @@ runs an instance of gdb against the vmlinux file which contains the symbols (not boot image such as bzImage, zImage, uImage...). In gdb the developer specifies the connection parameters and - connects to kgdb. Depending on which kgdb I/O modules exist in - the kernel for a given architecture, it may be possible to debug - the test machine's kernel with the development machine using a - rs232 or ethernet connection. + connects to kgdb. The type of connection a developer makes with + gdb depends on the availability of kgdb I/O modules compiled as + builtin's or kernel modules in the test machine's kernel. @@ -223,7 +222,7 @@ IMPORTANT NOTE: Using this option with kgdb over the console - (kgdboc) or kgdb over ethernet (kgdboe) is not supported. + (kgdboc) is not supported. @@ -249,18 +248,11 @@ (gdb) target remote /dev/ttyS0 - Example (kgdb to a terminal server): + Example (kgdb to a terminal server on tcp port 2012): % gdb ./vmlinux - (gdb) target remote udp:192.168.2.2:6443 - - - Example (kgdb over ethernet): - - - % gdb ./vmlinux - (gdb) target remote udp:192.168.2.2:6443 + (gdb) target remote 192.168.2.2:2012 Once connected, you can debug a kernel the way you would debug an -- cgit v1.2.3