diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-01-18 02:53:44 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-04-18 11:42:36 -0700 |
| commit | 5f0d5a3ae7cff0d7fa943c199c3a2e44f23e1fac (patch) | |
| tree | b7ba2116923723e193dfe7c633ec10056c6b1b53 /Documentation/RCU/rculist_nulls.txt | |
| parent | 4495c08e84729385774601b5146d51d9e5849f81 (diff) | |
mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU
A group of Linux kernel hackers reported chasing a bug that resulted
from their assumption that SLAB_DESTROY_BY_RCU provided an existence
guarantee, that is, that no block from such a slab would be reallocated
during an RCU read-side critical section. Of course, that is not the
case. Instead, SLAB_DESTROY_BY_RCU only prevents freeing of an entire
slab of blocks.
However, there is a phrase for this, namely "type safety". This commit
therefore renames SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU in order
to avoid future instances of this sort of confusion.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
[ paulmck: Add comments mentioning the old name, as requested by Eric
Dumazet, in order to help people familiar with the old name find
the new one. ]
Acked-by: David Rientjes <rientjes@google.com>
Diffstat (limited to 'Documentation/RCU/rculist_nulls.txt')
| -rw-r--r-- | Documentation/RCU/rculist_nulls.txt | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/Documentation/RCU/rculist_nulls.txt b/Documentation/RCU/rculist_nulls.txt index 18f9651ff23d..8151f0195f76 100644 --- a/Documentation/RCU/rculist_nulls.txt +++ b/Documentation/RCU/rculist_nulls.txt @@ -1,5 +1,5 @@ Using hlist_nulls to protect read-mostly linked lists and -objects using SLAB_DESTROY_BY_RCU allocations. +objects using SLAB_TYPESAFE_BY_RCU allocations. Please read the basics in Documentation/RCU/listRCU.txt @@ -7,7 +7,7 @@ Using special makers (called 'nulls') is a convenient way to solve following problem : A typical RCU linked list managing objects which are -allocated with SLAB_DESTROY_BY_RCU kmem_cache can +allocated with SLAB_TYPESAFE_BY_RCU kmem_cache can use following algos : 1) Lookup algo @@ -96,7 +96,7 @@ unlock_chain(); // typically a spin_unlock() 3) Remove algo -------------- Nothing special here, we can use a standard RCU hlist deletion. -But thanks to SLAB_DESTROY_BY_RCU, beware a deleted object can be reused +But thanks to SLAB_TYPESAFE_BY_RCU, beware a deleted object can be reused very very fast (before the end of RCU grace period) if (put_last_reference_on(obj) { |