From: David Rientjes <rientjes@google.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Mel Gorman <mgorman@suse.de>, Rik van Riel <riel@redhat.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Bob Liu <bob.liu@oracle.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [patch v2] mm, tmp: only collapse hugepages to nodes with affinity for zone_reclaim_mode
Date: Wed, 16 Jul 2014 17:54:20 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.02.1407161754000.23892@chino.kir.corp.google.com> (raw)
In-Reply-To: <53C69C7B.1010709@suse.cz>
On Wed, 16 Jul 2014, Vlastimil Babka wrote:
> I wonder if you could do this here?
>
> if (khugepaged_node_load[nid])
> return false;
>
> If the condition is true, it means you already checked the 'nid' node against
> all other nodes present in the pmd in a previous khugepaged_scan_pmd iteration.
> And if it passed then, it would also pass now. If meanwhile a new node was found
> and recorded, it was also checked against everything present at that point,
> including 'nid'. So it should be safe?
>
> The worst case (perfect interleaving page per page, so that "node != last_node"
> is true in each iteration) complexity then reduces from O(HPAGE_PMD_NR *
> MAX_NUMNODES) to O(HPAGE_PMD_NR + MAX_NUMNODES) iterations.
>
Excellent suggestion, thanks Vlastimil!
next prev parent reply other threads:[~2014-07-17 0:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-15 1:09 [patch] mm, thp: only collapse hugepages to nodes with affinity David Rientjes
2014-07-15 4:47 ` Dave Hansen
2014-07-15 23:17 ` David Rientjes
2014-07-16 0:13 ` [patch v2] mm, tmp: only collapse hugepages to nodes with affinity for zone_reclaim_mode David Rientjes
2014-07-16 1:22 ` Bob Liu
2014-07-16 15:47 ` Vlastimil Babka
2014-07-16 19:37 ` Hugh Dickins
2014-07-17 0:49 ` David Rientjes
2014-07-16 15:38 ` Vlastimil Babka
2014-07-17 0:54 ` David Rientjes [this message]
2014-07-17 0:59 ` [patch v3] mm, thp: " David Rientjes
2014-07-17 16:28 ` Dave Hansen
2014-07-17 21:48 ` [patch v4] " David Rientjes
2014-07-25 15:34 ` Mel Gorman
2014-07-28 8:42 ` [patch v3] " Vlastimil Babka
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