From: Mike Kravetz <mike.kravetz@oracle.com>
To: David Hildenbrand <david@redhat.com>,
Chen Wandun <chenwandun@huawei.com>,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/hugetlb: suppress wrong warning info when alloc gigantic page
Date: Thu, 4 Mar 2021 09:20:23 -0800 [thread overview]
Message-ID: <2cb384b9-1301-59a8-f678-c67ee26053b3@oracle.com> (raw)
In-Reply-To: <cf79e9a4-72ba-8fa0-0710-5e82a5b5e4d5@redhat.com>
On 3/4/21 1:35 AM, David Hildenbrand wrote:
> On 19.02.21 20:14, Mike Kravetz wrote:
>> On 2/19/21 4:39 AM, Chen Wandun wrote:
>>> If hugetlb_cma is enabled, it will skip boot time allocation
>>> when allocating gigantic page, that doesn't means allocation
>>> failure, so suppress this warning info.
>>>
>>
>> Normally the addition of warning messages is discouraged. However, in
>> this case the additional message provides value. Why?
>>
>> Prior to the commit cf11e85fc08c, one could have a kernel command line
>> that contains:
>>
>> hugepagesz=1G hugepages=16
>>
>> This would allocate 16 1G pages at boot time.
>>
>> After the commit, someone could specify a command line containing:
>>
>> hugepagesz=1G hugepages=16 hugetlb_cma=16G
>>
>> In this case, 16G of CMA will be reserved for 1G huge page allocations
>> after boot time. The parameter 'hugepages=16' is ignored, and the warning
>> message is logged. The warning message should only be logged when the
>> kernel parameter 'hugepages=' is ignored.
>>
>> IMO, it make sense to log a warning if ignoring a user specified parameter.
>> The user should not be attempting boot time allocation and CMA reservation
>> for 1G pages.
>>
>> I do not think we should drop the warning as the it tells the user thay
>> have specified two incompatible allocation options.
>>
>
> I agree. It has value.
>
Hi David,
Sorry my above reply was too quick as I did not take a close look at
the code/patch. See,
https://lore.kernel.org/mm-commits/YDAbeDsG7GhV6s6B@carbon.dhcp.thefacebook.com/
This patch is actually in Andrew's tree.
--
Mike Kravetz
next prev parent reply other threads:[~2021-03-04 17:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-19 12:39 [PATCH] mm/hugetlb: suppress wrong warning info when alloc gigantic page Chen Wandun
2021-02-19 19:14 ` Mike Kravetz
2021-03-04 9:35 ` David Hildenbrand
2021-03-04 17:20 ` Mike Kravetz [this message]
2021-03-04 17:21 ` David Hildenbrand
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=2cb384b9-1301-59a8-f678-c67ee26053b3@oracle.com \
--to=mike.kravetz@oracle.com \
--cc=akpm@linux-foundation.org \
--cc=chenwandun@huawei.com \
--cc=david@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
/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).