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From: David Laight <David.Laight@ACULAB.COM>
To: 'Chris Li' <chrisl@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	Yosry Ahmed <yosryahmed@google.com>,
	Nhat Pham <nphamcs@gmail.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	Chengming Zhou <zhouchengming@bytedance.com>,
	Barry Song <v-songbaohua@oppo.com>
Subject: RE: [PATCH v2] zswap: replace RB tree with xarray
Date: Fri, 1 Mar 2024 21:58:43 +0000	[thread overview]
Message-ID: <26e77602326d4e169a9484314cac2465@AcuMS.aculab.com> (raw)
In-Reply-To: <20240229-zswap-xarray-v2-1-e50284dfcdb1@kernel.org>

From: Chris Li
> Sent: 29 February 2024 08:46
> 
> Very deep RB tree requires rebalance at times. That
> contributes to the zswap fault latencies. Xarray does not
> need to perform tree rebalance. Replacing RB tree to xarray
> can have some small performance gain.
> 
> One small difference is that xarray insert might fail with
> ENOMEM, while RB tree insert does not allocate additional
> memory.

What is the difference in kernel memory use?
IIRC someone pointed out (in the rosebush thread) that xarray
uses a lot of kernel memory if the items are randomly distributed.

	David

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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

  parent reply	other threads:[~2024-03-01 21:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-29  8:46 Chris Li
2024-02-29  9:44 ` Chengming Zhou
2024-02-29 18:58   ` Chris Li
2024-03-01  7:24     ` Chengming Zhou
2024-03-01  9:38       ` Chris Li
2024-03-02 18:33         ` Chris Li
2024-03-01 21:58 ` David Laight [this message]
2024-03-01 22:33   ` Chris Li
2024-03-05  3:08   ` Yosry Ahmed

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