From: Baoquan He <bhe@redhat.com>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
david@redhat.com, akpm@linux-foundation.org
Subject: Re: [PATCH v2 4/4] mm/hugetl.c: warn out if expected count of huge pages adjustment is not achieved
Date: Tue, 11 Aug 2020 10:11:52 +0800 [thread overview]
Message-ID: <20200811021152.GW14854@MiWiFi-R3L-srv> (raw)
In-Reply-To: <b94f4dc1-5c53-68ca-2023-0aa4de4df8b7@oracle.com>
Hi Mike,
On 07/23/20 at 11:21am, Mike Kravetz wrote:
> On 7/23/20 2:11 AM, Baoquan He wrote:
...
> >> But is kernel expected to warn for all such situations where the user
> >> requested resources could not be allocated completely ? Otherwise, it
> >> does not make sense to add an warning for just one such situation.
> >
> > It's not for just one such situation, we have already had one to warn
> > out in mm/hugetlb.c, please check hugetlb_hstate_alloc_pages().
>
> Those are a little different in that they are warnings based on kernel
> command line parameters.
>
> > As Mike said, in one time of persistent huge page number setting,
> > comparing the old value with the new vlaue is good enough for customer
> > to get the information. However, if customer want to detect and analyze
> > previous setting failure, logging message will be helpful. So I think
> > logging the failure or partial success makes sense.
>
> I can understand the argument against adding a new warning for this.
> You could even argue that this condition has existed since the time
> hugetlb was added to the kernel which was long ago. And, nobody has
> complained enough to add a warning. I have even heard of a sysadmin
> practice of asking for a ridiculously large amount of hugetlb pages
> just so that the kernel will allocate as many as possible. They do
> not 'expect' to get the ridiculous amount they asked for. In such
> cases, this will be a new warning in their log.
>
> As mentioned in a previous e-mail, when one sets nr_hugepages by writing
> to the sysfs or proc file, one needs to read the file to determine if the
> number of requested pages were actually allocated. Anyone who does not
> do this is just asking for trouble. Yet, I imagine that it may happen.
>
> To be honest, I do not see this log message as something that would be
> helpful to end users. Rather, I could see this as being useful to support
> people. Support always asks for system logs and this could point out a
> possible issue with hugetlb usage.
>
> I do not feel strongly one way or another about adding the warning. Since
> it is fairly trivial and could help diagnose issues I am in favor of adding
> it. If people feel strongly that it should not be added, I am open to
> those arguments.
Ping!
It's been a while, seems no objection to log the message. Do you
consider accepting this patch or offering an Ack?
Thanks
Baoquan
next prev parent reply other threads:[~2020-08-11 2:12 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-23 3:22 [PATCH v2 0/4] mm/hugetlb: Small cleanup and improvement Baoquan He
2020-07-23 3:22 ` [PATCH v2 1/4] mm/hugetlb.c: make is_hugetlb_entry_hwpoisoned return bool Baoquan He
2020-07-23 4:46 ` Anshuman Khandual
2020-07-23 3:22 ` [PATCH v2 2/4] mm/hugetlb.c: Remove the unnecessary non_swap_entry() Baoquan He
2020-07-23 5:06 ` Anshuman Khandual
2020-07-23 6:14 ` Baoquan He
2020-07-23 8:52 ` Anshuman Khandual
2020-07-23 10:46 ` [PATCH v3 " Baoquan He
2020-07-23 3:22 ` [PATCH v2 3/4] doc/vm: fix typo in the hugetlb admin documentation Baoquan He
2020-07-23 5:17 ` Anshuman Khandual
2020-07-23 5:57 ` Baoquan He
2020-07-23 3:22 ` [PATCH v2 4/4] mm/hugetl.c: warn out if expected count of huge pages adjustment is not achieved Baoquan He
2020-07-23 6:16 ` Anshuman Khandual
2020-07-23 9:11 ` Baoquan He
2020-07-23 18:21 ` Mike Kravetz
2020-07-24 14:59 ` Baoquan He
2020-08-11 2:11 ` Baoquan He [this message]
2020-08-11 3:35 ` Mike Kravetz
2020-08-11 7:24 ` Michal Hocko
2020-08-11 23:11 ` Mike Kravetz
2020-08-24 21:57 ` [PATCH v2 0/4] mm/hugetlb: Small cleanup and improvement Mike Kravetz
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=20200811021152.GW14854@MiWiFi-R3L-srv \
--to=bhe@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=anshuman.khandual@arm.com \
--cc=david@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mike.kravetz@oracle.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).