rcu: Move from ->need_future_gp[] to ->gp_seq_needed

Browse source

One problem with the ->need_future_gp[] array is that the grace-period
assignment of each element changes as the grace periods complete.
This means that it is necessary to hold a lock when checking this
array to learn if a given grace period has already been requested.
This increase lock contention, which is the opposite of helpful.
This commit therefore replaces the ->need_future_gp[] with a single
->gp_seq_needed value and keeps it updated in the rcu_data structure.

This will enable reliable lockless checking of whether or not a given
grace period has already been requested.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

...

This commit is contained in:

Paul E. McKenney 2018-05-01 10:26:57 -07:00

parent aebc82644b

commit 7a1d0f23ad

2 changed files with 20 additions and 33 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

34

kernel/rcu/tree.c

View file

19

kernel/rcu/tree.h

View file