All of lore.kernel.org
 help / color / mirror / Atom feed
From: Oscar Salvador <osalvador@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>,
	Michal Hocko <mhocko@kernel.org>,
	Wei Yang <richard.weiyang@gmail.com>,
	Miaohe Lin <linmiaohe@huawei.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Oscar Salvador <osalvador@suse.de>
Subject: [PATCH 3/3] mm/memory_hotplug: Refactor hotadd_init_pgdat and try_online_node
Date: Mon,  7 Mar 2022 16:07:25 +0100	[thread overview]
Message-ID: <20220307150725.6810-4-osalvador@suse.de> (raw)
In-Reply-To: <20220307150725.6810-1-osalvador@suse.de>

Since we pre-allocate all nodes now, hotadd_init_pgdat() does
not need to return a pgdat struct, as that was meant for
__try_online_node() to check whether the node was succesfully
allocated.

Also get rid of the __ref as all functions hotadd_init_pgdat()
calls fall within the same section.

Also try to make more clear the return codes from __try_online_node().
__try_online_node() can return either 0, 1 or -errno (the latter not really
as the BUG_ON() would catch it before we return) but depending on the caller
that has different meanings.
For add_memory_resource(), when __try_online_node() returns non-zero,
it means that the node was already allocated and it does not need to bring
it up. It is fine not to check for -errno values because we do not
get to call register_one_node() when !set_node_online.
For those who call try_online_node(), so set_node_online is true, a value
other than zero means a failure (e.g: cpu_up() or find_and_online_cpu_nid()).

Signed-off-by: Oscar Salvador <osalvador@suse.de>
---
 mm/memory_hotplug.c | 35 ++++++++++++++---------------------
 1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 07cece9e22e4..5c92ac81a399 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1161,8 +1161,7 @@ static void reset_node_present_pages(pg_data_t *pgdat)
 	pgdat->node_present_pages = 0;
 }
 
-/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
-static pg_data_t __ref *hotadd_init_pgdat(int nid)
+static void hotadd_init_pgdat(int nid)
 {
 	struct pglist_data *pgdat = NODE_DATA(nid);
 
@@ -1182,8 +1181,6 @@ static pg_data_t __ref *hotadd_init_pgdat(int nid)
 	 * to access not-initialized zonelist, build here.
 	 */
 	build_all_zonelists(pgdat);
-
-	return pgdat;
 }
 
 /*
@@ -1193,31 +1190,27 @@ static pg_data_t __ref *hotadd_init_pgdat(int nid)
  * called by cpu_up() to online a node without onlined memory.
  *
  * Returns:
- * 1 -> a new node has been allocated
- * 0 -> the node is already online
- * -ENOMEM -> the node could not be allocated
+ * 1 -> The node has been initialized.
+ * 0 -> Either the node was already online, or we succesfully registered a new
+ *      one.
+ * -errno -> register_one_node() failed.
  */
 static int __try_online_node(int nid, bool set_node_online)
 {
-	pg_data_t *pgdat;
-	int ret = 1;
+	int ret;
 
 	if (node_online(nid))
 		return 0;
 
-	pgdat = hotadd_init_pgdat(nid);
-	if (!pgdat) {
-		pr_err("Cannot online node %d due to NULL pgdat\n", nid);
-		ret = -ENOMEM;
-		goto out;
-	}
+	hotadd_init_pgdat(nid);
+
+	if (!set_node_online)
+		return 1;
+
+	node_set_online(nid);
+	ret = register_one_node(nid);
+	BUG_ON(ret);
 
-	if (set_node_online) {
-		node_set_online(nid);
-		ret = register_one_node(nid);
-		BUG_ON(ret);
-	}
-out:
 	return ret;
 }
 
-- 
2.34.1


  parent reply	other threads:[~2022-03-07 15:07 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-07 15:07 [PATCH 0/3] A minor hotplug refactoring Oscar Salvador
2022-03-07 15:07 ` [PATCH 1/3] mm/page_alloc: Do not calculate node's total pages and memmap pages when empty Oscar Salvador
2022-04-28 12:13   ` David Hildenbrand
2022-05-05  9:09     ` Oscar Salvador
2022-03-07 15:07 ` [PATCH 2/3] mm/memory_hotplug: Reset node's state when empty during offline Oscar Salvador
2022-04-28 12:30   ` David Hildenbrand
2022-05-05 10:37     ` Oscar Salvador
2022-03-07 15:07 ` Oscar Salvador [this message]
2022-04-28 12:35   ` [PATCH 3/3] mm/memory_hotplug: Refactor hotadd_init_pgdat and try_online_node David Hildenbrand
2022-05-05  9:17     ` Oscar Salvador
2022-04-27 21:05 ` [PATCH 0/3] A minor hotplug refactoring Andrew Morton

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220307150725.6810-4-osalvador@suse.de \
    --to=osalvador@suse.de \
    --cc=akpm@linux-foundation.org \
    --cc=david@redhat.com \
    --cc=linmiaohe@huawei.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=richard.weiyang@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.