From: Michal Hocko <mhocko@kernel.org>
To: Wei Yang <richardw.yang@linux.intel.com>
Cc: 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: Mon, 20 Jan 2020 10:36:46 +0100 [thread overview]
Message-ID: <20200120093646.GL18451@dhcp22.suse.cz> (raw)
In-Reply-To: <20200119030636.11899-2-richardw.yang@linux.intel.com>
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.
>
> - 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
next prev parent reply other threads:[~2020-01-20 9:36 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 [this message]
2020-01-20 22:25 ` Wei Yang
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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