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authorMichal Marek <mmarek@suse.cz>2013-02-25 21:50:05 +0100
committerMichal Marek <mmarek@suse.cz>2013-02-25 21:51:57 +0100
commite3900e74f26fc924c8e9e2a922bd40369b0bb517 (patch)
tree6e868575d346032ba9408f350c6e5369e0e52b0d /Documentation/RCU/whatisRCU.txt
parent62dc989921df2a98d1a73aacd085abe941cb9828 (diff)
parent02f3e53a131c8aa3fe3c954058f1add5beeae621 (diff)
Merge branch 'kbuild/rc-fixes' into kbuild/kconfig
There is one kconfig fix in the rc-fixes branch that I forgot to submit for 3.8, so let's add it to the kconfig branch for 3.9-rc1.
Diffstat (limited to 'Documentation/RCU/whatisRCU.txt')
-rw-r--r--Documentation/RCU/whatisRCU.txt17
1 files changed, 12 insertions, 5 deletions
diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
index bf0f6de2aa00..0cc7820967f4 100644
--- a/Documentation/RCU/whatisRCU.txt
+++ b/Documentation/RCU/whatisRCU.txt
@@ -499,6 +499,8 @@ The foo_reclaim() function might appear as follows:
{
struct foo *fp = container_of(rp, struct foo, rcu);
+ foo_cleanup(fp->a);
+
kfree(fp);
}
@@ -521,6 +523,12 @@ o Use call_rcu() -after- removing a data element from an
read-side critical sections that might be referencing that
data item.
+If the callback for call_rcu() is not doing anything more than calling
+kfree() on the structure, you can use kfree_rcu() instead of call_rcu()
+to avoid having to write your own callback:
+
+ kfree_rcu(old_fp, rcu);
+
Again, see checklist.txt for additional rules governing the use of RCU.
@@ -773,8 +781,8 @@ a single atomic update, converting to RCU will require special care.
Also, the presence of synchronize_rcu() means that the RCU version of
delete() can now block. If this is a problem, there is a callback-based
-mechanism that never blocks, namely call_rcu(), that can be used in
-place of synchronize_rcu().
+mechanism that never blocks, namely call_rcu() or kfree_rcu(), that can
+be used in place of synchronize_rcu().
7. FULL LIST OF RCU APIs
@@ -789,9 +797,7 @@ RCU list traversal:
list_for_each_entry_rcu
hlist_for_each_entry_rcu
hlist_nulls_for_each_entry_rcu
-
- list_for_each_continue_rcu (to be deprecated in favor of new
- list_for_each_entry_continue_rcu)
+ list_for_each_entry_continue_rcu
RCU pointer/list update:
@@ -813,6 +819,7 @@ RCU: Critical sections Grace period Barrier
rcu_read_unlock synchronize_rcu
rcu_dereference synchronize_rcu_expedited
call_rcu
+ kfree_rcu
bh: Critical sections Grace period Barrier