From: Thomas Gleixner <tglx@linutronix.de>
To: Shaohua Li <shli@fb.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Fenghua Yu <fenghua.yu@intel.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] x86/intel_rdt: reinitialize cbm for new group allocation
Date: Mon, 9 Jan 2017 22:58:13 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.20.1701092244110.3534@nanos> (raw)
In-Reply-To: <91a513378542f2d81e39baf954d8f8c447fd1943.1483747472.git.shli@fb.com>
On Fri, 6 Jan 2017, Shaohua Li wrote:
> rdtgroup_rmdir deletes a group and frees the closid, but doesn't
> reiniaialize domain's cbm to default for the closid. Next time the
> closid is allocated again, 'schemata' will show old cbm.
Rightfully so. Because that's the value which is in the configuration
MSR. That's perfectly fine because nothing can use that closid and therefor
the configuration MSR is completely irrelevant until the closid is reused.
> We can do the reinitialization at free/alloc closid, but sounds doing it
> at alloc is more nartual.
What you are doing is not natural, it's just wrong.
Assume the admin wants to keep the 'max_cbm' value for a domain and
therefor does not update the schemata file, but the MSR still contains the
old value. Not what you really want, right?
If you really want to have the CBM values reset to max_cbm then this needs
to be done when the directory is removed and this needs to be written to
the hardware as well on all affected packages. Not sure if that's worth the
effort.
Thanks,
tglx
prev parent reply other threads:[~2017-01-09 21:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-07 0:05 [PATCH] x86/intel_rdt: reinitialize cbm for new group allocation Shaohua Li
2017-01-09 21:56 ` Fenghua Yu
2017-01-09 22:03 ` Thomas Gleixner
2017-01-09 22:17 ` Fenghua Yu
2017-01-09 22:24 ` Shaohua Li
2017-01-09 21:58 ` Thomas Gleixner [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=alpine.DEB.2.20.1701092244110.3534@nanos \
--to=tglx@linutronix.de \
--cc=fenghua.yu@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=shli@fb.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).