From: Tarun Sahu <tsahu@linux.ibm.com>
To: "Verma, Vishal L" <vishal.l.verma@intel.com>,
"Schofield, Alison" <alison.schofield@intel.com>
Cc: "Williams, Dan J" <dan.j.williams@intel.com>,
"Jiang, Dave" <dave.jiang@intel.com>,
"linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>,
"nvdimm@lists.linux.dev" <nvdimm@lists.linux.dev>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"aneesh.kumar@linux.ibm.com" <aneesh.kumar@linux.ibm.com>,
"jaypatel@linux.ibm.com" <jaypatel@linux.ibm.com>
Subject: Re: [PATCH] dax/kmem: Pass valid argument to memory_group_register_static
Date: Thu, 22 Jun 2023 12:45:40 +0530 [thread overview]
Message-ID: <878rcc0xyb.fsf@linux.ibm.com> (raw)
In-Reply-To: <b7e620efa0de6b9f7a8ae9ce51d8dd562f384cdc.camel@intel.com>
Hi Vishal,
"Verma, Vishal L" <vishal.l.verma@intel.com> writes:
> On Wed, 2023-06-21 at 11:36 +0530, Tarun Sahu wrote:
>> Hi Alison,
>>
>> Alison Schofield <alison.schofield@intel.com> writes:
>>
>> > On Tue, Jun 20, 2023 at 07:33:32PM +0530, Tarun Sahu wrote:
>> > > memory_group_register_static takes maximum number of pages as the argument
>> > > while dev_dax_kmem_probe passes total_len (in bytes) as the argument.
>> >
>> > This sounds like a fix. An explanation of the impact and a fixes tag
>> > may be needed. Also, wondering how you found it.
>> >
>> Yes, it is a fix, I found it during dry code walk-through.
>> There is not any impact as such. As,
>> memory_group_register_static just set the max_pages limit which
>> is used in auto_movable_zone_for_pfn to determine the zone.
>>
>> which might cause these condition to behave differently,
>>
>> This will be true always so jump will happen to kernel_zone
>> if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages))
>> goto kernel_zone;
>> ---
>> kernel_zone:
>> return default_kernel_zone_for_pfn(nid, pfn, nr_pages);
>>
>> ---
>>
>> Here, In below, zone_intersects compare range will be larger as nr_pages
>> will be higher (derived from total_len passed in dev_dax_kmem_probe).
>>
>> static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
>> unsigned long nr_pages)
>> {
>> struct pglist_data *pgdat = NODE_DATA(nid);
>> int zid;
>>
>> for (zid = 0; zid < ZONE_NORMAL; zid++) {
>> struct zone *zone = &pgdat->node_zones[zid];
>>
>> if (zone_intersects(zone, start_pfn, nr_pages))
>> return zone;
>> }
>>
>> return &pgdat->node_zones[ZONE_NORMAL];
>> }
>>
>> In Mostly cases, ZONE_NORMAL will be returned. But there is no
>> crash/panic issues involved here, only decision making on selecting zone
>> is affected.
>>
>
> Hi Tarun,
>
> Good find! With a Fixes tag, and perhaps inclusion of a bit more of
> this detail described in the commit message, feel free to add:
>
Thanks for reviewing, sent the updated version.
> Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
prev parent reply other threads:[~2023-06-22 7:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-20 14:03 [PATCH] dax/kmem: Pass valid argument to memory_group_register_static Tarun Sahu
2023-06-20 23:18 ` Alison Schofield
2023-06-21 6:06 ` Tarun Sahu
2023-06-21 6:42 ` Verma, Vishal L
2023-06-22 7:15 ` Tarun Sahu [this message]
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=878rcc0xyb.fsf@linux.ibm.com \
--to=tsahu@linux.ibm.com \
--cc=alison.schofield@intel.com \
--cc=aneesh.kumar@linux.ibm.com \
--cc=dan.j.williams@intel.com \
--cc=dave.jiang@intel.com \
--cc=jaypatel@linux.ibm.com \
--cc=linux-cxl@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=nvdimm@lists.linux.dev \
--cc=vishal.l.verma@intel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).