Revert "local_t Documentation update"
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.
Signed-off-by Li Zefan <[email protected]>
--- Documentation/local_ops.txt | 23 ----------------------- 1 files changed, 0 insertions(+), 23 deletions(-)
Documentation/local_ops.txt +0 -23
@@ -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 Since no memory - synchronization is done by the writer CPU, an outdated copy of the - variable can be read when reading some _other_ cpu's variables.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
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.Signed-off-by Li Zefan <[email protected]>
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@@ -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
Quoted 6 lines · Mathieu Desnoyers
Quoted 5 lines · * Li Zefan ([email protected]) wrote:
This reverts commit
e1265205c0ee3919c3f2c750662630154c8faab2.It's a duplicate commit of commit
74beb9db77930be476b267ec8518a642f39a04bf, resulting in a duplicate section.
Quoted 7 lines
Quoted 2 lines
Signed-off-by Li Zefan <[email protected]>Thanks, I guess it's been merged twice somehow :S
Yeap, I guess so.