From: Christoph Lameter <cl@linux.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
Andrew Morton <akpm@linux-foundation.org>,
hannes@cmpxchg.org,
Linaro Kernel Mailman List <linaro-kernel@lists.linaro.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
vinmenon@codeaurora.org, shashim@codeaurora.org,
Michal Hocko <mhocko@suse.cz>,
mgorman@suse.de, dave@stgolabs.net, koct9i@gmail.com,
Linux Memory Management List <linux-mm@kvack.org>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC] vmstat: Avoid waking up idle-cpu to service shepherd work
Date: Fri, 27 Mar 2015 06:11:44 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.11.1503270610430.19514@gentwo.org> (raw)
In-Reply-To: <20150327093023.GA32047@worktop.ger.corp.intel.com>
On Fri, 27 Mar 2015, Peter Zijlstra wrote:
> > We could align the base on 8 bytes to gain an extra bit in the pointer
> > and use that bit to indicate the running state. Then these sites can
> > spin on that bit while we can change the actual base pointer.
>
> Even though tvec_base has ____cacheline_aligned stuck on, most are
> allocated using kzalloc_node() which does not actually respect that but
> already guarantees a minimum u64 alignment, so I think we can use that
> third bit without too much magic.
Create a new slab cache for this purpose that does the proper aligning?
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Lameter <cl@linux.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
Andrew Morton <akpm@linux-foundation.org>,
hannes@cmpxchg.org,
Linaro Kernel Mailman List <linaro-kernel@lists.linaro.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
vinmenon@codeaurora.org, shashim@codeaurora.org,
Michal Hocko <mhocko@suse.cz>,
mgorman@suse.de, dave@stgolabs.net, koct9i@gmail.com,
Linux Memory Management List <linux-mm@kvack.org>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC] vmstat: Avoid waking up idle-cpu to service shepherd work
Date: Fri, 27 Mar 2015 06:11:44 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.11.1503270610430.19514@gentwo.org> (raw)
In-Reply-To: <20150327093023.GA32047@worktop.ger.corp.intel.com>
On Fri, 27 Mar 2015, Peter Zijlstra wrote:
> > We could align the base on 8 bytes to gain an extra bit in the pointer
> > and use that bit to indicate the running state. Then these sites can
> > spin on that bit while we can change the actual base pointer.
>
> Even though tvec_base has ____cacheline_aligned stuck on, most are
> allocated using kzalloc_node() which does not actually respect that but
> already guarantees a minimum u64 alignment, so I think we can use that
> third bit without too much magic.
Create a new slab cache for this purpose that does the proper aligning?
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next prev parent reply other threads:[~2015-03-27 11:11 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-26 5:39 [RFC] vmstat: Avoid waking up idle-cpu to service shepherd work Viresh Kumar
2015-03-26 5:39 ` Viresh Kumar
2015-03-26 20:18 ` Andrew Morton
2015-03-26 20:18 ` Andrew Morton
2015-03-27 4:49 ` Viresh Kumar
2015-03-27 4:49 ` Viresh Kumar
2015-03-27 9:16 ` Peter Zijlstra
2015-03-27 9:16 ` Peter Zijlstra
2015-03-27 9:30 ` Peter Zijlstra
2015-03-27 9:30 ` Peter Zijlstra
2015-03-27 11:11 ` Christoph Lameter [this message]
2015-03-27 11:11 ` Christoph Lameter
2015-03-27 12:02 ` Peter Zijlstra
2015-03-27 12:02 ` Peter Zijlstra
2015-03-27 19:45 ` Christoph Lameter
2015-03-27 19:45 ` Christoph Lameter
2015-03-28 4:28 ` Viresh Kumar
2015-03-28 4:28 ` Viresh Kumar
2015-03-28 11:41 ` Peter Zijlstra
2015-03-28 11:41 ` Peter Zijlstra
2015-03-28 4:18 ` Viresh Kumar
2015-03-28 4:18 ` Viresh Kumar
2015-03-28 9:53 ` Peter Zijlstra
2015-03-28 9:53 ` Peter Zijlstra
2015-03-28 11:57 ` viresh kumar
2015-03-28 11:57 ` viresh kumar
2015-03-28 12:04 ` Viresh Kumar
2015-03-28 12:04 ` Viresh Kumar
2015-03-28 13:44 ` Peter Zijlstra
2015-03-28 13:44 ` Peter Zijlstra
2015-03-29 10:24 ` Peter Zijlstra
2015-03-29 10:24 ` Peter Zijlstra
2015-03-30 12:02 ` Viresh Kumar
2015-03-30 12:02 ` Viresh Kumar
2015-03-30 12:47 ` Peter Zijlstra
2015-03-30 12:47 ` Peter Zijlstra
2015-03-30 13:14 ` Viresh Kumar
2015-03-30 13:14 ` Viresh Kumar
2015-03-30 13:59 ` Peter Zijlstra
2015-03-30 13:59 ` Peter Zijlstra
2015-03-30 16:17 ` Viresh Kumar
2015-03-30 16:17 ` Viresh Kumar
2015-03-30 16:25 ` Peter Zijlstra
2015-03-30 16:25 ` Peter Zijlstra
2015-03-29 12:01 ` Viresh Kumar
2015-03-29 12:01 ` Viresh Kumar
2015-03-29 17:24 ` Peter Zijlstra
2015-03-29 17:24 ` Peter Zijlstra
2015-03-30 15:08 ` Michal Hocko
2015-03-30 15:08 ` Michal Hocko
2015-03-30 15:14 ` Peter Zijlstra
2015-03-30 15:14 ` Peter Zijlstra
2015-03-30 15:42 ` Christoph Lameter
2015-03-30 15:42 ` Christoph Lameter
2015-03-27 14:19 ` Michal Hocko
2015-03-27 14:19 ` Michal Hocko
2015-03-28 4:34 ` Viresh Kumar
2015-03-28 4:34 ` Viresh Kumar
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