From: Andrew Morton <akpm@linux-foundation.org>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: linux-mm@kvack.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Andi Kleen <ak@linux.intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Alex Shi <alex.shu@intel.com>, Jan Beulich <jbeulich@novell.com>,
Robert Richter <robert.richter@amd.com>,
Andy Lutomirski <luto@amacapital.net>,
Andrea Arcangeli <aarcange@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Hugh Dickins <hughd@google.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Mel Gorman <mgorman@suse.de>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-mips@linux-mips.org, linux-sh@vger.kernel.org,
sparclinux@vger.kernel.org
Subject: Re: [PATCH v4 0/8] Avoid cache trashing on clearing huge/gigantic page
Date: Thu, 13 Sep 2012 16:05:06 -0700 [thread overview]
Message-ID: <20120913160506.d394392a.akpm@linux-foundation.org> (raw)
In-Reply-To: <1345470757-12005-1-git-send-email-kirill.shutemov@linux.intel.com>
On Mon, 20 Aug 2012 16:52:29 +0300
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> wrote:
> Clearing a 2MB huge page will typically blow away several levels of CPU
> caches. To avoid this only cache clear the 4K area around the fault
> address and use a cache avoiding clears for the rest of the 2MB area.
>
> This patchset implements cache avoiding version of clear_page only for
> x86. If an architecture wants to provide cache avoiding version of
> clear_page it should to define ARCH_HAS_USER_NOCACHE to 1 and implement
> clear_page_nocache() and clear_user_highpage_nocache().
Patchset looks nice to me, but the changelogs are terribly short of
performance measurements. For this sort of change I do think it is
important that pretty exhaustive testing be performed, and that the
results (or a readable summary of them) be shown. And that testing
should be designed to probe for slowdowns, not just the speedups!
next prev parent reply other threads:[~2012-09-13 23:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-20 13:52 [PATCH v4 0/8] Avoid cache trashing on clearing huge/gigantic page Kirill A. Shutemov
2012-08-20 13:52 ` [PATCH v4 1/8] THP: Use real address for NUMA policy Kirill A. Shutemov
2012-08-20 13:52 ` [PATCH v4 2/8] THP: Pass fault address to __do_huge_pmd_anonymous_page() Kirill A. Shutemov
2012-08-20 13:52 ` [PATCH v4 3/8] hugetlb: pass fault address to hugetlb_no_page() Kirill A. Shutemov
2012-08-20 13:52 ` [PATCH v4 4/8] mm: pass fault address to clear_huge_page() Kirill A. Shutemov
2012-08-20 13:52 ` [PATCH v4 5/8] x86: Add clear_page_nocache Kirill A. Shutemov
2012-08-20 13:52 ` [PATCH v4 6/8] mm: make clear_huge_page cache clear only around the fault address Kirill A. Shutemov
2012-08-20 13:52 ` [PATCH v4 7/8] x86: switch the 64bit uncached page clear to SSE/AVX v2 Kirill A. Shutemov
2012-08-20 13:52 ` [PATCH v4 8/8] mm: implement vm.clear_huge_page_nocache sysctl Kirill A. Shutemov
2012-09-12 10:09 ` [PATCH v4 0/8] Avoid cache trashing on clearing huge/gigantic page Kirill A. Shutemov
2012-09-13 23:05 ` Andrew Morton [this message]
2012-09-14 5:52 ` Ingo Molnar
2012-09-25 14:27 ` Kirill A. Shutemov
2012-09-25 19:33 ` Andrea Arcangeli
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