From: Andi Kleen <andi@firstfloor.org>
To: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>,
Peter Zijlstra <peterz@infradead.org>,
Linux MM <linux-mm@kvack.org>, Michal Hocko <mhocko@suse.cz>
Subject: Re: [RFC PATCH v2 0/7] Speculative page faults
Date: Fri, 18 Nov 2016 06:08:24 -0800 [thread overview]
Message-ID: <871sy8284n.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <cover.1479465699.git.ldufour@linux.vnet.ibm.com> (Laurent Dufour's message of "Fri, 18 Nov 2016 12:08:44 +0100")
Laurent Dufour <ldufour@linux.vnet.ibm.com> writes:
> This is a port on kernel 4.8 of the work done by Peter Zijlstra to
> handle page fault without holding the mm semaphore.
One of the big problems with patches like this today is that it is
unclear what mmap_sem actually protects. It's a big lock covering lots
of code. Parts in the core VM, but also do VM callbacks in file systems
and drivers rely on it too?
IMHO the first step is a comprehensive audit and then writing clear
documentation on what it is supposed to protect. Then based on that such
changes can be properly evaluated.
-Andi
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next prev parent reply other threads:[~2016-11-18 14:08 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-17 12:33 mmap_sem bottleneck Laurent Dufour
2016-10-17 12:51 ` Peter Zijlstra
2016-10-18 14:50 ` Laurent Dufour
2016-10-18 15:01 ` Kirill A. Shutemov
2016-10-18 15:02 ` Peter Zijlstra
2016-11-18 11:08 ` [RFC PATCH v2 0/7] Speculative page faults Laurent Dufour
2016-11-18 11:08 ` [RFC PATCH v2 1/7] mm: Dont assume page-table invariance during faults Laurent Dufour
2016-11-18 11:08 ` [RFC PATCH v2 2/7] mm: Prepare for FAULT_FLAG_SPECULATIVE Laurent Dufour
2016-11-18 11:08 ` [RFC PATCH v2 3/7] mm: Introduce pte_spinlock Laurent Dufour
2016-11-18 11:08 ` [RFC PATCH v2 4/7] mm: VMA sequence count Laurent Dufour
2016-11-18 11:08 ` [RFC PATCH v2 5/7] SRCU free VMAs Laurent Dufour
2016-11-18 11:08 ` [RFC PATCH v2 6/7] mm: Provide speculative fault infrastructure Laurent Dufour
2016-11-18 11:08 ` [RFC PATCH v2 7/7] mm,x86: Add speculative pagefault handling Laurent Dufour
2016-11-18 14:08 ` Andi Kleen [this message]
2016-12-01 8:34 ` [RFC PATCH v2 0/7] Speculative page faults Laurent Dufour
2016-12-01 12:50 ` Balbir Singh
2016-12-01 13:26 ` Laurent Dufour
2016-12-02 14:10 ` Michal Hocko
2016-10-17 12:57 ` mmap_sem bottleneck Michal Hocko
2016-10-20 7:23 ` Laurent Dufour
2016-10-20 10:55 ` Michal Hocko
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