From: Tim Chen <tim.c.chen@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiebin Sun <jiebin.sun@intel.com>,
vasily.averin@linux.dev, shakeelb@google.com, dennis@kernel.org,
tj@kernel.org, cl@linux.com, ebiederm@xmission.com,
legion@kernel.org, manfred@colorfullife.com,
alexander.mikhalitsyn@virtuozzo.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, tim.c.chen@intel.com,
feng.tang@intel.com, ying.huang@intel.com, tianyou.li@intel.com,
wangyang.guo@intel.com
Subject: Re: [PATCH v4] ipc/msg: mitigate the lock contention with percpu counter
Date: Wed, 07 Sep 2022 15:10:11 -0700 [thread overview]
Message-ID: <dbe336c7d7618db4c56613fa53479c18df1e0b9b.camel@linux.intel.com> (raw)
In-Reply-To: <20220907143427.0ce54bbf096943ffca197fee@linux-foundation.org>
On Wed, 2022-09-07 at 14:34 -0700, Andrew Morton wrote:
>
> I think this concept of a percpu_counter_add() which is massively
> biased to the write side and with very rare reading is a legitimate
> use-case. Perhaps it should become an addition to the formal interface.
> Something like
>
> /*
> * comment goes here
> */
> static inline void percpu_counter_add_local(struct percpu_counter *fbc,
> s64 amount)
> {
> percpu_counter_add_batch(fbc, amount, INT_MAX);
> }
>
> and percpu_counter_sub_local(), I guess.
>
> The only instance I can see is
> block/blk-cgroup-rwstat.h:blkg_rwstat_add() which is using INT_MAX/2
> because it always uses percpu_counter_sum_positive() on the read side.
>
> But that makes two!
Sure. We can create this function and use it for both cases. No objections.
Tim
next prev parent reply other threads:[~2022-09-07 22:10 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-02 15:22 [PATCH] ipc/msg.c: mitigate the lock contention with percpu counter Jiebin Sun
2022-09-02 16:06 ` Andrew Morton
2022-09-05 11:54 ` Sun, Jiebin
2022-09-02 16:27 ` Shakeel Butt
2022-09-05 12:02 ` Sun, Jiebin
2022-09-06 18:44 ` Tim Chen
2022-09-07 9:39 ` Sun, Jiebin
2022-09-07 20:43 ` Andrew Morton
2022-09-07 17:25 ` [PATCH v4] ipc/msg: " Jiebin Sun
2022-09-07 16:01 ` Tim Chen
2022-09-07 21:34 ` Andrew Morton
2022-09-07 22:10 ` Tim Chen [this message]
2022-09-08 8:25 ` Sun, Jiebin
2022-09-08 15:38 ` Andrew Morton
2022-09-08 16:15 ` Dennis Zhou
2022-09-03 19:35 ` [PATCH] ipc/msg.c: " Manfred Spraul
2022-09-05 12:12 ` Sun, Jiebin
[not found] ` <20220905193516.846647-1-jiebin.sun@intel.com>
[not found] ` <20220905193516.846647-3-jiebin.sun@intel.com>
2022-09-05 19:31 ` [PATCH v2 1/2] percpu: Add percpu_counter_add_local Shakeel Butt
2022-09-06 8:41 ` Sun, Jiebin
2022-09-05 19:35 ` [PATCH v2 2/2] ipc/msg: mitigate the lock contention with percpu counter Jiebin Sun
2022-09-06 16:54 ` [PATCH v3 0/2] ipc/msg: mitigate the lock contention in ipc/msg Jiebin Sun
2022-09-06 16:54 ` [PATCH v3 2/2] ipc/msg: mitigate the lock contention with percpu counter Jiebin Sun
2022-09-09 20:36 ` [PATCH v5 0/2] ipc/msg: mitigate the lock contention in ipc/msg Jiebin Sun
2022-09-09 20:36 ` [PATCH v5 1/2] percpu: Add percpu_counter_add_local and percpu_counter_sub_local Jiebin Sun
2022-09-09 16:37 ` Tim Chen
2022-09-10 1:37 ` kernel test robot
2022-09-10 8:15 ` kernel test robot
2022-09-10 8:26 ` kernel test robot
2022-09-09 20:36 ` [PATCH v5 2/2] ipc/msg: mitigate the lock contention with percpu counter Jiebin Sun
2022-09-09 16:11 ` Tim Chen
2022-09-13 19:25 ` [PATCH v6 0/2] ipc/msg: mitigate the lock contention in ipc/msg Jiebin Sun
2022-09-13 19:25 ` [PATCH v6 1/2] percpu: Add percpu_counter_add_local and percpu_counter_sub_local Jiebin Sun
2022-09-18 11:08 ` Manfred Spraul
2022-09-20 6:01 ` Sun, Jiebin
2022-09-13 19:25 ` [PATCH v6 2/2] ipc/msg: mitigate the lock contention with percpu counter Jiebin Sun
2022-09-18 12:53 ` Manfred Spraul
2022-09-20 2:36 ` Sun, Jiebin
2022-09-20 4:53 ` Manfred Spraul
2022-09-20 5:50 ` Sun, Jiebin
2022-09-20 15:08 ` [PATCH] ipc/msg: avoid negative value by overflow in msginfo Jiebin Sun
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