From: Michal Hocko <mhocko@kernel.org>
To: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Oscar Salvador <osalvador@techadventures.net>,
Vlastimil Babka <vbabka@suse.cz>,
Pavel Tatashin <pasha.tatashin@oracle.com>,
Reza Arbab <arbab@linux.vnet.ibm.com>,
Igor Mammedov <imammedo@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH 2/2] mm: do not warn on offline nodes unless the specific node is explicitly requested
Date: Wed, 23 May 2018 16:06:02 +0200 [thread overview]
Message-ID: <20180523140601.GQ20441@dhcp22.suse.cz> (raw)
In-Reply-To: <11e26a4e-552e-b1dc-316e-ce3e92973556@linux.vnet.ibm.com>
On Wed 23-05-18 19:15:51, Anshuman Khandual wrote:
> On 05/23/2018 06:25 PM, Michal Hocko wrote:
> > when adding memory to a node that is currently offline.
> >
> > The VM_WARN_ON is just too loud without a good reason. In this
> > particular case we are doing
> > alloc_pages_node(node, GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN, order)
> >
> > so we do not insist on allocating from the given node (it is more a
> > hint) so we can fall back to any other populated node and moreover we
> > explicitly ask to not warn for the allocation failure.
> >
> > Soften the warning only to cases when somebody asks for the given node
> > explicitly by __GFP_THISNODE.
>
> node hint passed here eventually goes into __alloc_pages_nodemask()
> function which then picks up the applicable zonelist irrespective of
> the GFP flag __GFP_THISNODE.
__GFP_THISNODE should enforce the given node without any fallbacks
unless something has changed recently.
> Though we can go into zones of other
> nodes if the present node (whose zonelist got picked up) does not
> have any memory in it's zones. So warning here might not be without
> any reason.
I am not sure I follow. Are you suggesting a different VM_WARN_ON?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-05-23 14:06 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-23 12:55 [PATCH 0/2] few memory hotplug fixes Michal Hocko
2018-05-23 12:55 ` Michal Hocko
2018-05-23 12:55 ` [PATCH 1/2] mm, memory_hotplug: make has_unmovable_pages more robust Michal Hocko
2018-05-23 12:55 ` Michal Hocko
2018-05-23 13:14 ` Pavel Tatashin
2018-05-23 12:55 ` [PATCH 2/2] mm: do not warn on offline nodes unless the specific node is explicitly requested Michal Hocko
2018-05-23 12:55 ` Michal Hocko
2018-05-23 13:14 ` Pavel Tatashin
2018-05-23 13:45 ` Anshuman Khandual
2018-05-23 14:06 ` Michal Hocko [this message]
2018-05-24 3:22 ` Anshuman Khandual
2018-05-24 8:00 ` Michal Hocko
2018-05-25 4:50 ` Anshuman Khandual
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