From: Wei Yang <richardw.yang@linux.intel.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Wei Yang <richardw.yang@linux.intel.com>,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, yang.shi@linux.alibaba.com
Subject: Re: [PATCH 1/8] mm/migrate.c: skip node check if done in last round
Date: Tue, 21 Jan 2020 06:25:40 +0800 [thread overview]
Message-ID: <20200120222540.GA32314@richard> (raw)
In-Reply-To: <20200120093646.GL18451@dhcp22.suse.cz>
On Mon, Jan 20, 2020 at 10:36:46AM +0100, Michal Hocko wrote:
>On Sun 19-01-20 11:06:29, Wei Yang wrote:
>> Before move page to target node, we would check if the node id is valid.
>> In case we would try to move pages to the same target node, it is not
>> necessary to do the check each time.
>>
>> This patch tries to skip the check if the node has been checked.
>>
>> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
>> ---
>> mm/migrate.c | 19 +++++++++++--------
>> 1 file changed, 11 insertions(+), 8 deletions(-)
>>
>> diff --git a/mm/migrate.c b/mm/migrate.c
>> index 430fdccc733e..ba7cf4fa43a0 100644
>> --- a/mm/migrate.c
>> +++ b/mm/migrate.c
>> @@ -1612,15 +1612,18 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
>> goto out_flush;
>> addr = (unsigned long)untagged_addr(p);
>>
>> - err = -ENODEV;
>> - if (node < 0 || node >= MAX_NUMNODES)
>> - goto out_flush;
>> - if (!node_state(node, N_MEMORY))
>> - goto out_flush;
>> + /* Check node if it is not checked. */
>> + if (current_node == NUMA_NO_NODE || node != current_node) {
>> + err = -ENODEV;
>> + if (node < 0 || node >= MAX_NUMNODES)
>> + goto out_flush;
>> + if (!node_state(node, N_MEMORY))
>> + goto out_flush;
>
>This makes the code harder to read IMHO. The original code checks the
>valid node first and it doesn't conflate that with the node caching
>logic which your change does.
>
I am sorry, would you mind showing me an example about the conflate in my
change? I don't get it.
>>
>> - err = -EACCES;
>> - if (!node_isset(node, task_nodes))
>> - goto out_flush;
>> + err = -EACCES;
>> + if (!node_isset(node, task_nodes))
>> + goto out_flush;
>> + }
>>
>> if (current_node == NUMA_NO_NODE) {
>> current_node = node;
>> --
>> 2.17.1
>
>--
>Michal Hocko
>SUSE Labs
--
Wei Yang
Help you, Help me
next prev parent reply other threads:[~2020-01-20 22:25 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-19 3:06 [PATCH 0/8] mm/migrate.c: cleanup on do_pages_move() Wei Yang
2020-01-19 3:06 ` [PATCH 1/8] mm/migrate.c: skip node check if done in last round Wei Yang
2020-01-20 9:36 ` Michal Hocko
2020-01-20 22:25 ` Wei Yang [this message]
2020-01-21 8:42 ` Michal Hocko
2020-01-22 0:36 ` Wei Yang
2020-01-22 8:16 ` Michal Hocko
2020-01-19 3:06 ` [PATCH 2/8] mm/migrate.c: not necessary to check start and i Wei Yang
2020-01-19 22:14 ` David Rientjes
2020-01-20 0:31 ` Wei Yang
2020-01-20 9:45 ` Michal Hocko
2020-01-19 3:06 ` [PATCH 3/8] mm/migrate.c: reform the last call on do_move_pages_to_node() Wei Yang
2020-01-20 9:46 ` Michal Hocko
2020-01-20 22:27 ` Wei Yang
2020-01-19 3:06 ` [PATCH 4/8] mm/migrate.c: wrap do_move_pages_to_node() and store_status() Wei Yang
2020-01-20 9:49 ` Michal Hocko
2020-01-19 3:06 ` [PATCH 5/8] mm/migrate.c: check pagelist in move_pages_and_store_status() Wei Yang
2020-01-20 9:52 ` Michal Hocko
2020-01-19 3:06 ` [PATCH 6/8] mm/migrate.c: handle same node and add failure in the same way Wei Yang
2020-01-20 10:01 ` Michal Hocko
2020-01-19 3:06 ` [PATCH 7/8] mm/migrate.c: move page on next iteration Wei Yang
2020-01-20 10:02 ` Michal Hocko
2020-01-21 1:22 ` Wei Yang
2020-01-21 8:43 ` Michal Hocko
2020-01-22 0:40 ` Wei Yang
2020-01-22 8:17 ` Michal Hocko
2020-01-19 3:06 ` [PATCH 8/8] mm/migrate.c: use break instead of goto out_flush Wei Yang
2020-01-20 10:03 ` Michal Hocko
2020-01-21 1:22 ` Wei Yang
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