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Date: Mon, 27 Jul 2015 09:08:42 +0200
From: Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH] mm: add resched points to
 remap_pmd_range/ioremap_pmd_range
Message-ID: <20150727070840.GB11317@dhcp22.suse.cz>
References: <1437688476-3399-3-git-send-email-sbaugh@catern.com>
 <20150724070420.GF4103@dhcp22.suse.cz>
 <20150724165627.GA3458@Sligo.logfs.org>
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To: =?iso-8859-1?Q?J=F6rn?= Engel <joern@purestorage.com>
Cc: Spencer Baugh <sbaugh@catern.com>, Toshi Kani <toshi.kani@hp.com>, Andrew Morton <akpm@linux-foundation.org>, Fengguang Wu <fengguang.wu@intel.com>, Joern Engel <joern@logfs.org>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Mel Gorman <mgorman@suse.de>, Johannes Weiner <hannes@cmpxchg.org>, Shachar Raindel <raindel@mellanox.com>, Boaz Harrosh <boaz@plexistor.com>, Andy Lutomirski <luto@amacapital.net>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Andrey Ryabinin <a.ryabinin@samsung.com>, Roman Pen <r.peniaev@gmail.com>, Andrey Konovalov <adech.fo@gmail.com>, Eric Dumazet <edumazet@google.com>, Dmitry Vyukov <dvyukov@google.com>, Rob Jones <rob.jones@codethink.co.uk>, WANG Chao <chaowang@redhat.com>, open list <linux-kernel@vger.kernel.org>, "open list:MEMORY MANAGEMENT" <linux-mm@kvack.org>, Spencer Baugh <Spencer.baugh@purestorage.com>

On Fri 24-07-15 09:56:27, Jorn Engel wrote:
> On Fri, Jul 24, 2015 at 09:04:21AM +0200, Michal Hocko wrote:
> > On Thu 23-07-15 14:54:33, Spencer Baugh wrote:
> > > From: Joern Engel <joern@logfs.org>
> > > 
> > > Mapping large memory spaces can be slow and prevent high-priority
> > > realtime threads from preempting lower-priority threads for a long time.
> > 
> > How can a lower priority task block the high priority one? Do you have
> > preemption disabled?
> 
> Yes.

Yes what? PREEMT enabled and still low priority task starving a high
priority one? What is your exact setup?
-- 
Michal Hocko
SUSE Labs

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