| Message ID | 20230418070259.1353785-1-qiang1.zhang@intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | rcu/kvfree: Make drain_page_cache() call return directly if cache is disabled | expand |
On Tue, Apr 18, 2023 at 03:02:59PM +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 c8ba2be026fa..ce995fc1c644 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; > + > Should we check for zero? -- Uladzislau Rezki
> 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 c8ba2be026fa..ce995fc1c644 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; > + > >Should we check for zero? > I am so sorry, It's my mistake. I will resend. Thanks Zqiang > >-- >Uladzislau Rezki
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index c8ba2be026fa..ce995fc1c644 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(+)