From 6501d44ee8c3193da491c662f450613647c8b218 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Thu, 17 Jan 2008 15:21:20 -0800 Subject: [PATCH] --- yaml --- r: 75533 b: refs/heads/master c: 34aebfd3bdc93c0c5614f1f61e43b6ddc4be52ae h: refs/heads/master i: 75531: 982818e03d54dcc2729bf73d4fc687b322b78e17 v: v3 --- [refs] | 2 +- trunk/Documentation/local_ops.txt | 23 ----------------------- 2 files changed, 1 insertion(+), 24 deletions(-) diff --git a/[refs] b/[refs] index a0cba85a77b9..d73b0852c173 100644 --- a/[refs] +++ b/[refs] @@ -1,2 +1,2 @@ --- -refs/heads/master: 545c4423335469de06af7f7c95e97c1122c1c818 +refs/heads/master: 34aebfd3bdc93c0c5614f1f61e43b6ddc4be52ae diff --git a/trunk/Documentation/local_ops.txt b/trunk/Documentation/local_ops.txt index 1a45f11e645e..4269a1105b37 100644 --- a/trunk/Documentation/local_ops.txt +++ b/trunk/Documentation/local_ops.txt @@ -45,29 +45,6 @@ long fails. The definition looks like : typedef struct { atomic_long_t a; } local_t; -* Rules to follow when using local atomic operations - -- Variables touched by local ops must be per cpu variables. -- _Only_ the CPU owner of these variables must write to them. -- This CPU can use local ops from any context (process, irq, softirq, nmi, ...) - to update its local_t variables. -- Preemption (or interrupts) must be disabled when using local ops in - process context to make sure the process won't be migrated to a - different CPU between getting the per-cpu variable and doing the - actual local op. -- When using local ops in interrupt context, no special care must be - taken on a mainline kernel, since they will run on the local CPU with - preemption already disabled. I suggest, however, to explicitly - disable preemption anyway to make sure it will still work correctly on - -rt kernels. -- Reading the local cpu variable will provide the current copy of the - variable. -- Reads of these variables can be done from any CPU, because updates to - "long", aligned, variables are always atomic. Since no memory - synchronization is done by the writer CPU, an outdated copy of the - variable can be read when reading some _other_ cpu's variables. - - * Rules to follow when using local atomic operations - Variables touched by local ops must be per cpu variables.