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author | Uladzislau Rezki (Sony) <urezki@gmail.com> | 2020-05-26 00:47:58 +0300 |
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committer | Paul E. McKenney <paulmck@kernel.org> | 2020-06-29 21:59:26 +0300 |
commit | 3042f83f19bec2e0cd356f72b39e4d816e8cd5ff (patch) | |
tree | 87f16b6c8070e945c2967f03d47e2b18779645e1 /lib | |
parent | ce4dce123fdcb5f209752d13f9f06926be65fc78 (diff) | |
download | linux-3042f83f19bec2e0cd356f72b39e4d816e8cd5ff.tar.xz |
rcu: Support reclaim for head-less object
Update the kvfree_call_rcu() function with head-less support.
This allows RCU to reclaim objects without an embedded rcu_head.
tree-RCU:
We introduce two chains of arrays to store SLAB-backed and vmalloc
pointers, each. Storage in either of these arrays does not require
embedding an rcu_head within the object.
Maintaining the arrays may become impossible due to high memory
pressure. For such cases there is an emergency path. Objects with
rcu_head inside are just queued on a backup rcu_head list. Later on
that list is drained. As for the head-less variant, as the current
context can sleep, the following emergency measures are applied:
a) Synchronously wait until a grace period has elapsed.
b) Call kvfree().
tiny-RCU:
For double argument calls, there are no new changes in behavior. For
single argument call, kvfree() is directly inlined on the current
stack after a synchronize_rcu() call. Note that for tiny-RCU, any
call to synchronize_rcu() is actually a quiescent state, therefore
it does nothing.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Co-developed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'lib')
0 files changed, 0 insertions, 0 deletions