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| -rw-r--r-- | Documentation/memory-barriers.txt | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index 06e14efd8662..d414e145f912 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -396,6 +396,10 @@ Memory barriers come in four basic varieties: (2) Address-dependency barriers (historical). + [!] This section is marked as HISTORICAL: For more up-to-date + information, including how compiler transformations related to pointer + comparisons can sometimes cause problems, see + Documentation/RCU/rcu_dereference.rst. An address-dependency barrier is a weaker form of read barrier. In the case where two loads are performed such that the second depends on the @@ -556,6 +560,9 @@ There are certain things that the Linux kernel memory barriers do not guarantee: ADDRESS-DEPENDENCY BARRIERS (HISTORICAL) ---------------------------------------- +[!] This section is marked as HISTORICAL: For more up-to-date information, +including how compiler transformations related to pointer comparisons can +sometimes cause problems, see Documentation/RCU/rcu_dereference.rst. As of v4.15 of the Linux kernel, an smp_mb() was added to READ_ONCE() for DEC Alpha, which means that about the only people who need to pay attention |