| Message ID | 20230127184651.3681682-1-riel@surriel.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | ipc,namespace: fix free vs allocation race | expand |
Rik van Riel <riel@surriel.com> writes: > The IPC namespace code frees ipc_namespace structures asynchronously, > via a work queue item. This results in ipc_namespace structures being > freed very slowly, and the allocation path getting false failures > since the to-be-freed ipc_namespace structures have not been freed > yet. > > Fix that by having the allocator wait when there are ipc_namespace > structures pending to be freed. > > Also speed up the freeing of ipc_namespace structures. We had some > discussions about this last year, and ended up trying out various > "nicer" ideas that did not work, so I went back to the original, > with Al Viro's suggestion for a helper function: > > https://lore.kernel.org/all/Yg8StKzTWh+7FLuA@zeniv-ca.linux.org.uk/ > > This series fixes both the false allocation failures, and the slow > freeing of ipc_namespace structures. > > v3: remove mq_put_mnt (thank you Giuseppe) > v2: a few more fs/namespace.c cleanups suggested by Al Viro (thank you!) Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
On Fri, Jan 27, 2023 at 01:46:49PM -0500, Rik van Riel wrote: > The IPC namespace code frees ipc_namespace structures asynchronously, > via a work queue item. This results in ipc_namespace structures being > freed very slowly, and the allocation path getting false failures > since the to-be-freed ipc_namespace structures have not been freed > yet. > > Fix that by having the allocator wait when there are ipc_namespace > structures pending to be freed. > > Also speed up the freeing of ipc_namespace structures. We had some > discussions about this last year, and ended up trying out various > "nicer" ideas that did not work, so I went back to the original, > with Al Viro's suggestion for a helper function: > > https://lore.kernel.org/all/Yg8StKzTWh+7FLuA@zeniv-ca.linux.org.uk/ > > This series fixes both the false allocation failures, and the slow > freeing of ipc_namespace structures. > > v3: remove mq_put_mnt (thank you Giuseppe) > v2: a few more fs/namespace.c cleanups suggested by Al Viro (thank you!) Applied (#work.namespace)