* [PATCH] rcu/kvfree: Make drain_page_cache() call return directly if cache is disabled
@ 2023-04-18 7:02 Zqiang
2023-04-18 12:05 ` Uladzislau Rezki
0 siblings, 1 reply; 3+ messages in thread
From: Zqiang @ 2023-04-18 7:02 UTC (permalink / raw)
To: urezki, paulmck, frederic, joel, qiang1.zhang
Cc: qiang.zhang1211, rcu, linux-kernel
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;
+
raw_spin_lock_irqsave(&krcp->lock, flags);
page_list = llist_del_all(&krcp->bkvcache);
WRITE_ONCE(krcp->nr_bkv_objs, 0);
--
2.32.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] rcu/kvfree: Make drain_page_cache() call return directly if cache is disabled
2023-04-18 7:02 [PATCH] rcu/kvfree: Make drain_page_cache() call return directly if cache is disabled Zqiang
@ 2023-04-18 12:05 ` Uladzislau Rezki
2023-04-18 12:25 ` Zhang, Qiang1
0 siblings, 1 reply; 3+ messages in thread
From: Uladzislau Rezki @ 2023-04-18 12:05 UTC (permalink / raw)
To: Zqiang; +Cc: urezki, paulmck, frederic, joel, qiang.zhang1211, rcu,
linux-kernel
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
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: [PATCH] rcu/kvfree: Make drain_page_cache() call return directly if cache is disabled
2023-04-18 12:05 ` Uladzislau Rezki
@ 2023-04-18 12:25 ` Zhang, Qiang1
0 siblings, 0 replies; 3+ messages in thread
From: Zhang, Qiang1 @ 2023-04-18 12:25 UTC (permalink / raw)
To: Uladzislau Rezki
Cc: paulmck@kernel.org, frederic@kernel.org, joel@joelfernandes.org,
qiang.zhang1211@gmail.com, rcu@vger.kernel.org,
linux-kernel@vger.kernel.org
> 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
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-04-18 12:26 UTC | newest]
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2023-04-18 7:02 [PATCH] rcu/kvfree: Make drain_page_cache() call return directly if cache is disabled Zqiang
2023-04-18 12:05 ` Uladzislau Rezki
2023-04-18 12:25 ` Zhang, Qiang1
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