From: Andi Kleen <ak@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>,
"Huang, Ying" <ying.huang@intel.com>,
dave.hansen@intel.com, aaron.lu@intel.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Hugh Dickins <hughd@google.com>,
Shaohua Li <shli@kernel.org>, Minchan Kim <minchan@kernel.org>,
Rik van Riel <riel@redhat.com>,
Andrea Arcangeli <aarcange@redhat.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Hillf Danton <hillf.zj@alibaba-inc.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Jonathan Corbet <corbet@lwn.net>
Subject: Re: [PATCH v5 3/9] mm/swap: Split swap cache into 64MB trunks
Date: Wed, 11 Jan 2017 15:19:37 -0800 [thread overview]
Message-ID: <20170111231937.GH8388@tassilo.jf.intel.com> (raw)
In-Reply-To: <20170111150940.25d951a121a62e1b7eff6f8d@linux-foundation.org>
> Switching from a single radix-tree to an array of radix-trees to reduce
> contention seems a bit hacky. That we can do this and have everything
> continue to work tells me that we're simply using an inappropriate data
> structure to hold this info.
What would you use instead?
A tree with fine grained locking?
FWIW too fine grained locking (e.g. on every node) is usually a bad idea:
it slows down the single thread performance and it causes much more overhead
when there is actual contention because too much time is spent bouncing cache
lines around.
So I actually like the "a little bit more fine grained, but not too much"
approach.
Or a hash table?
Not sure if this would work here.
-Andi
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next prev parent reply other threads:[~2017-01-11 23:19 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-11 17:55 [PATCH v5 0/9] mm/swap: Regular page swap optimizations Tim Chen
2017-01-11 17:55 ` [PATCH v5 1/9] mm/swap: Fix kernel message in swap_info_get() Tim Chen
2017-01-11 17:55 ` [PATCH v5 2/9] mm/swap: Add cluster lock Tim Chen
2017-01-11 23:00 ` Andrew Morton
2017-01-11 23:07 ` Jonathan Corbet
2017-01-11 23:15 ` Andrew Morton
2017-01-12 1:47 ` Huang, Ying
2017-01-12 1:58 ` Andrew Morton
2017-01-12 2:51 ` Huang, Ying
2017-01-14 4:37 ` [Update][PATCH " Huang, Ying
2017-01-12 1:23 ` [PATCH " Huang, Ying
2017-01-11 17:55 ` [PATCH v5 3/9] mm/swap: Split swap cache into 64MB trunks Tim Chen
2017-01-11 23:09 ` Andrew Morton
2017-01-11 23:19 ` Andi Kleen [this message]
2017-01-12 16:47 ` Tim Chen
2017-01-11 17:55 ` [PATCH v5 4/9] mm/swap: skip read ahead for unreferenced swap slots Tim Chen
2017-01-11 17:55 ` [PATCH v5 5/9] mm/swap: Allocate swap slots in batches Tim Chen
2017-01-11 17:55 ` [PATCH v5 6/9] mm/swap: Free swap slots in batch Tim Chen
2017-01-11 17:55 ` [PATCH v5 7/9] mm/swap: Add cache for swap slots allocation Tim Chen
2017-01-17 2:55 ` [Update][PATCH " Huang, Ying
2017-01-17 10:16 ` Michal Hocko
2017-01-17 17:24 ` Chen, Tim C
2017-01-17 20:03 ` Michal Hocko
2017-01-17 20:31 ` Chen, Tim C
2017-01-17 21:42 ` Tim Chen
2017-01-18 12:45 ` Michal Hocko
2017-01-18 18:03 ` Tim Chen
2017-01-18 18:15 ` Michal Hocko
2017-01-11 17:55 ` [PATCH v5 8/9] mm/swap: Enable swap slots cache usage Tim Chen
2017-01-11 17:55 ` [PATCH v5 9/9] mm/swap: Skip readahead only when swap slot cache is enabled Tim Chen
2017-01-16 12:02 ` [PATCH v5 0/9] mm/swap: Regular page swap optimizations Michal Hocko
2017-01-17 1:06 ` Huang, Ying
2017-01-17 7:49 ` Michal Hocko
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