| Message ID | 20230418122702.1378299-1-qiang1.zhang@intel.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 0d9e733231cb70a6c20fb1198abad75c67b08956 |
| Headers | show |
| Series | [v2] rcu/kvfree: Make drain_page_cache() call return directly if cache is disabled | expand |
On Tue, Apr 18, 2023 at 08:27:02PM +0800, Zqiang wrote: > If the rcu_min_cached_objs is set to zero at boot params, the > krcp->page_cache_work will not be triggered to fill page cache, > and the put_cached_bnode() also does not fill page cache, this > also means the krcp->bkvcache is always empty, so not need to > acquire unnecessary krcp->lock to get page from krcp->bkvcache, > this commit therefore make drain_page_cache() return directly if > the rcu_min_cached_objs is zero. > > Signed-off-by: Zqiang <qiang1.zhang@intel.com> > --- > kernel/rcu/tree.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index 93faf9f5c58f..00620a2117de 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -2924,6 +2924,9 @@ drain_page_cache(struct kfree_rcu_cpu *krcp) > struct llist_node *page_list, *pos, *n; > int freed = 0; > > + if (!rcu_min_cached_objs) > + return 0; > + > raw_spin_lock_irqsave(&krcp->lock, flags); > page_list = llist_del_all(&krcp->bkvcache); > WRITE_ONCE(krcp->nr_bkv_objs, 0); > -- > 2.32.0 > Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> -- Uladzislau Rezki
On Thu, Apr 20, 2023 at 01:06:27PM +0200, Uladzislau Rezki wrote: > On Tue, Apr 18, 2023 at 08:27:02PM +0800, Zqiang wrote: > > If the rcu_min_cached_objs is set to zero at boot params, the > > krcp->page_cache_work will not be triggered to fill page cache, > > and the put_cached_bnode() also does not fill page cache, this > > also means the krcp->bkvcache is always empty, so not need to > > acquire unnecessary krcp->lock to get page from krcp->bkvcache, > > this commit therefore make drain_page_cache() return directly if > > the rcu_min_cached_objs is zero. > > > > Signed-off-by: Zqiang <qiang1.zhang@intel.com> > > --- > > kernel/rcu/tree.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > > index 93faf9f5c58f..00620a2117de 100644 > > --- a/kernel/rcu/tree.c > > +++ b/kernel/rcu/tree.c > > @@ -2924,6 +2924,9 @@ drain_page_cache(struct kfree_rcu_cpu *krcp) > > struct llist_node *page_list, *pos, *n; > > int freed = 0; > > > > + if (!rcu_min_cached_objs) > > + return 0; > > + > > raw_spin_lock_irqsave(&krcp->lock, flags); > > page_list = llist_del_all(&krcp->bkvcache); > > WRITE_ONCE(krcp->nr_bkv_objs, 0); > > -- > > 2.32.0 > > > Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Queued for further testing and review, thank you both! Thanx, Paul
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 93faf9f5c58f..00620a2117de 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2924,6 +2924,9 @@ drain_page_cache(struct kfree_rcu_cpu *krcp) struct llist_node *page_list, *pos, *n; int freed = 0; + if (!rcu_min_cached_objs) + return 0; + raw_spin_lock_irqsave(&krcp->lock, flags); page_list = llist_del_all(&krcp->bkvcache); WRITE_ONCE(krcp->nr_bkv_objs, 0);
If the rcu_min_cached_objs is set to zero at boot params, the krcp->page_cache_work will not be triggered to fill page cache, and the put_cached_bnode() also does not fill page cache, this also means the krcp->bkvcache is always empty, so not need to acquire unnecessary krcp->lock to get page from krcp->bkvcache, this commit therefore make drain_page_cache() return directly if the rcu_min_cached_objs is zero. Signed-off-by: Zqiang <qiang1.zhang@intel.com> --- kernel/rcu/tree.c | 3 +++ 1 file changed, 3 insertions(+)