On Fri, Jun 03, 2022 at 11:55:10AM +0200, Uladzislau Rezki wrote: > On Thu, Jun 02, 2022 at 11:32:23PM +0000, Joel Fernandes wrote: > > On Thu, Jun 02, 2022 at 10:06:44AM +0200, Uladzislau Rezki (Sony) wrote: > > > Currently the monitor work is scheduled with a fixed interval that > > > is HZ/20 or each 50 milliseconds. The drawback of such approach is > > > a low utilization of page slot in some scenarios. The page can store > > > up to 512 records. For example on Android system it can look like: > > > > > > <snip> > > > kworker/3:0-13872 [003] .... 11286.007048: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000026522604 nr_records=1 > > > kworker/3:0-13872 [003] .... 11286.015638: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000095ed6fca nr_records=2 > > > kworker/1:2-20434 [001] .... 11286.051230: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000044872ffd nr_records=1 > > > kworker/1:2-20434 [001] .... 11286.059322: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000026522604 nr_records=2 > > > kworker/0:1-20052 [000] .... 11286.095295: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000044872ffd nr_records=2 > > > kworker/0:1-20052 [000] .... 11286.103418: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x00000000cbcf05db nr_records=1 > > > kworker/2:3-14372 [002] .... 11286.135155: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000095ed6fca nr_records=2 > > > kworker/2:3-14372 [002] .... 11286.135198: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000044872ffd nr_records=1 > > > kworker/1:2-20434 [001] .... 11286.155377: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x00000000cbcf05db nr_records=5 > > > kworker/2:3-14372 [002] .... 11286.167181: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000026522604 nr_records=5 > > > kworker/1:2-20434 [001] .... 11286.179202: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x000000008ef95e14 nr_records=1 > > > kworker/2:3-14372 [002] .... 11286.187398: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x00000000c597d297 nr_records=6 > > > kworker/3:0-13872 [003] .... 11286.187445: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000050bf92e2 nr_records=3 > > > kworker/1:2-20434 [001] .... 11286.198975: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x00000000cbcf05db nr_records=4 > > > kworker/1:2-20434 [001] .... 11286.207203: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000095ed6fca nr_records=4 > > > <snip> > > > > > > where a page only carries few records to reclaim a memory. In order to > > > improve batching and make utilization more efficient the patch introduces > > > a drain interval that can be set either to KFREE_DRAIN_JIFFIES_MAX or > > > KFREE_DRAIN_JIFFIES_MIN. It is adjusted if a flood is detected, in this > > > case a memory reclaim occurs more often whereas in mostly idle cases the > > > interval is set to its maximum timeout that improves the utilization of > > > page slots. > > > > > > Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx> > > > > Reviewed-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx> > > > Thanks! > > This patch makes the interval hard-coded in some sense so you can not change > it in runtime, only recompilation. If there is a need or request we can make > both as module_param(). Yes, this seems a good first step. > If we are to do that we can just add one extra patch on top of it. Yes. thanks, - Joel
