Messages in this thread | | | Date | Fri, 21 Aug 2015 19:42:30 +0200 | From | Oleg Nesterov <> | Subject | [PATCH v2 0/8] Add rcu_sync infrastructure to avoid _expedited() in percpu-rwsem |
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Hello,
Now that sb->s_writers was changed to use percpu_rw_semaphore let me send v2.
Changes:
- whitespace fix in 1/8.
- remove EXPORT_SYMBOL() in 3/8, currently rcu_sync has no modular users.
- 5/8 is new. This ugly hack pairs with another one: "shift percpu_counter_destroy() into destroy_super_work()" https://git.kernel.org/cgit/linux/kernel/git/viro/vfs.git/commit/?h=for-next&id=853b39a7c82826b8413048feec7bf08e98ce7a84 They both will be reverted later.
The problem is that we have 2 series routed via different trees, RCU and VFS. We need this hack to ensure that this series won't break alloc_super() which currently assumes that destroy_super()->percpu_free_rwsem() is safe after kzalloc(). This way these 2 series do not depend on each other, we can test/change/revert/etc them independently.
We will add rcu_sync_dtor() into deactivate_locked_super() later and revert both hacks. Oleg.
include/linux/percpu-rwsem.h | 3 +- include/linux/rcusync.h | 56 +++++++++++++++ kernel/locking/percpu-rwsem.c | 85 ++++++++--------------- kernel/rcu/Makefile | 2 +- kernel/rcu/sync.c | 151 +++++++++++++++++++++++++++++++++++++++++ 5 files changed, 240 insertions(+), 57 deletions(-)
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