From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Alex Thorlton <athorlton@sgi.com>, Ingo Molnar <mingo@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
"Eric W . Biederman" <ebiederm@xmission.com>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Andi Kleen <ak@linux.intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Dave Hansen <dave.hansen@intel.com>,
Dave Jones <davej@redhat.com>,
David Howells <dhowells@redhat.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Kees Cook <keescook@chromium.org>, Mel Gorman <mgorman@suse.de>,
Michael Kerrisk <mtk.manpages@gmail.com>,
Oleg Nesterov <oleg@redhat.com>, Rik van Riel <riel@redhat.com>,
Robin Holt <robinmholt@gmail.com>,
Sedat Dilek <sedat.dilek@gmail.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 8/9] mm: implement split page table lock for PMD level
Date: Fri, 13 Sep 2013 17:25:13 +0300 (EEST) [thread overview]
Message-ID: <20130913142513.A62ABE0090@blue.fi.intel.com> (raw)
In-Reply-To: <20130913132435.GD21832@twins.programming.kicks-ass.net>
Peter Zijlstra wrote:
> On Fri, Sep 13, 2013 at 04:06:15PM +0300, Kirill A. Shutemov wrote:
> > The basic idea is the same as with PTE level: the lock is embedded into
> > struct page of table's page.
> >
> > Split pmd page table lock only makes sense on big machines.
> > Let's say >= 32 CPUs for now.
>
> Why is this? Couldn't I generate the same amount of contention on PMD
> level as I can on PTE level in the THP case?
Hm. You are right. You just need more memory for that.
Do you want it to be "4" too?
--
Kirill A. Shutemov
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next prev parent reply other threads:[~2013-09-13 14:25 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20130910074748.GA2971@gmail.com>
2013-09-13 13:06 ` [PATCH 0/9] split page table lock for PMD tables Kirill A. Shutemov
2013-09-13 13:06 ` [PATCH 1/9] mm: rename SPLIT_PTLOCKS to SPLIT_PTE_PTLOCKS Kirill A. Shutemov
2013-09-13 15:20 ` Dave Hansen
2013-09-13 13:06 ` [PATCH 2/9] mm: convert mm->nr_ptes to atomic_t Kirill A. Shutemov
2013-09-13 13:06 ` [PATCH 3/9] mm: introduce api for split page table lock for PMD level Kirill A. Shutemov
2013-09-13 13:19 ` Peter Zijlstra
2013-09-13 14:22 ` Kirill A. Shutemov
2013-09-13 13:06 ` [PATCH 4/9] mm, thp: change pmd_trans_huge_lock() to return taken lock Kirill A. Shutemov
2013-09-13 13:06 ` [PATCH 5/9] mm, thp: move ptl taking inside page_check_address_pmd() Kirill A. Shutemov
2013-09-13 13:06 ` [PATCH 6/9] mm, thp: do not access mm->pmd_huge_pte directly Kirill A. Shutemov
2013-09-13 13:06 ` [PATCH 7/9] mm: convent the rest to new page table lock api Kirill A. Shutemov
2013-09-13 13:06 ` [PATCH 8/9] mm: implement split page table lock for PMD level Kirill A. Shutemov
2013-09-13 13:24 ` Peter Zijlstra
2013-09-13 14:25 ` Kirill A. Shutemov [this message]
2013-09-13 14:52 ` Peter Zijlstra
2013-09-13 13:36 ` Peter Zijlstra
2013-09-13 14:25 ` Kirill A. Shutemov
2013-09-13 15:45 ` Naoya Horiguchi
2013-09-13 19:57 ` Dave Hansen
2013-09-13 13:06 ` [PATCH 9/9] x86, mm: enable " Kirill A. Shutemov
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