| Message ID | 20240515125332.9306-1-frederic@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | rcu: Remove several redundant memory barriers | expand |
On 15/05/24 14:53, Frederic Weisbecker wrote: > Reviewing Valentin's patchset made me stare at some memory barriers > on the way. Sorry not sorry? :-) > Here is some removal proposal. Some may be beneficial on > runtime (fqs snapshot with potentially as many smp_mb() as the number > of online CPUs for each GP). Some happen on more rare path. In any > case they clarify code reviews so we don't stumble upon mysterious > barriers. > > Thanks. > > Frederic Weisbecker (6): > rcu: Remove full ordering on second EQS snapshot > rcu: Remove superfluous full memory barrier upon first EQS snapshot > rcu/exp: Remove superfluous full memory barrier upon first EQS > snapshot > rcu: Remove full memory barrier on boot time eqs sanity check > rcu: Remove full memory barrier on RCU stall printout > rcu/exp: Remove redundant full memory barrier at the end of GP > > .../Tree-RCU-Memory-Ordering.rst | 6 +++--- > kernel/rcu/tree.c | 21 +++++++------------ > kernel/rcu/tree_exp.h | 16 +++++++++++--- > kernel/rcu/tree_stall.h | 4 ++-- > 4 files changed, 26 insertions(+), 21 deletions(-) > > -- > 2.44.0
Le Wed, May 15, 2024 at 07:32:30PM +0200, Valentin Schneider a écrit : > On 15/05/24 14:53, Frederic Weisbecker wrote: > > Reviewing Valentin's patchset made me stare at some memory barriers > > on the way. > > Sorry not sorry? :-) ;-))
Reviewing Valentin's patchset made me stare at some memory barriers on the way. Here is some removal proposal. Some may be beneficial on runtime (fqs snapshot with potentially as many smp_mb() as the number of online CPUs for each GP). Some happen on more rare path. In any case they clarify code reviews so we don't stumble upon mysterious barriers. Thanks. Frederic Weisbecker (6): rcu: Remove full ordering on second EQS snapshot rcu: Remove superfluous full memory barrier upon first EQS snapshot rcu/exp: Remove superfluous full memory barrier upon first EQS snapshot rcu: Remove full memory barrier on boot time eqs sanity check rcu: Remove full memory barrier on RCU stall printout rcu/exp: Remove redundant full memory barrier at the end of GP .../Tree-RCU-Memory-Ordering.rst | 6 +++--- kernel/rcu/tree.c | 21 +++++++------------ kernel/rcu/tree_exp.h | 16 +++++++++++--- kernel/rcu/tree_stall.h | 4 ++-- 4 files changed, 26 insertions(+), 21 deletions(-)