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Revert "local_t Documentation update"

PATCH In review Li Zefan 2 participants 3 messages Jan 17, 2008 Documentation

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Li Zefan

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PATCH 1/1 Revert "local_t Documentation update"

This reverts commit e1265205c0ee3919c3f2c750662630154c8faab2.

It's a duplicate commit of commit 74beb9db77930be476b267ec8518a642f39a04bf, resulting in a duplicate section.

---
 Documentation/local_ops.txt |   23 -----------------------
 1 files changed, 0 insertions(+), 23 deletions(-)
Documentation/local_ops.txt +0 -23
index 1a45f11..4269a11 100644
@@ -68,29 +68,6 @@ typedef struct { atomic_long_t a; } local_t;
   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.
-- _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-  synchronization is done by the writer CPU, an outdated copy of the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.
-
-
 * How to use local atomic operations
 
 #include <linux/percpu.h>
Signature · 1 line
1.5.3.rc7
Acked-by on v1 1/1
#1 lore raw
Quoted 7 lines · * Li Zefan ([email protected]) wrote:

This reverts commit e1265205c0ee3919c3f2c750662630154c8faab2.

It's a duplicate commit of commit 74beb9db77930be476b267ec8518a642f39a04bf, resulting in a duplicate section.

Thanks, I guess it's been merged twice somehow :S

Quoted 41 lines
---
 Documentation/local_ops.txt |   23 -----------------------
 1 files changed, 0 insertions(+), 23 deletions(-)
Documentation/local_ops.txt +0 -23
index 1a45f11..4269a11 100644
@@ -68,29 +68,6 @@ typedef struct { atomic_long_t a; } local_t;
   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.
-- _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.
-
-
 * How to use local atomic operations
 
 #include <linux/percpu.h>
Signature · 1 line
1.5.3.rc7
Signature · 3 lines
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68