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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-11-27 20:20:40 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-12-05 22:57:53 +0300 |
| commit | 9ad3c143d7d6942c66f27bc6c18f5df638f70aff (patch) | |
| tree | b0b52f72cd5d03677b2d643feaaa7220aa109f29 /Documentation/RCU/rcu_dereference.txt | |
| parent | 98c1ec7cefaadbf65680d116c3d8612b93a841a0 (diff) | |
| download | linux-9ad3c143d7d6942c66f27bc6c18f5df638f70aff.tar.xz | |
doc: De-emphasize smp_read_barrier_depends
This commit keeps only the historical and low-level discussion of
smp_read_barrier_depends().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Adjusted to allow for David Howells feedback on prior commit. ]
Diffstat (limited to 'Documentation/RCU/rcu_dereference.txt')
| -rw-r--r-- | Documentation/RCU/rcu_dereference.txt | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/Documentation/RCU/rcu_dereference.txt b/Documentation/RCU/rcu_dereference.txt index 1acb26b09b48..ab96227bad42 100644 --- a/Documentation/RCU/rcu_dereference.txt +++ b/Documentation/RCU/rcu_dereference.txt @@ -122,11 +122,7 @@ o Be very careful about comparing pointers obtained from Note that if checks for being within an RCU read-side critical section are not required and the pointer is never dereferenced, rcu_access_pointer() should be used in place - of rcu_dereference(). The rcu_access_pointer() primitive - does not require an enclosing read-side critical section, - and also omits the smp_read_barrier_depends() included in - rcu_dereference(), which in turn should provide a small - performance gain in some CPUs (e.g., the DEC Alpha). + of rcu_dereference(). o The comparison is against a pointer that references memory that was initialized "a long time ago." The reason |