From: Keith Busch <kbusch@kernel.org>
To: Tony Battersby <tonyb@cybernetics.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
iommu@lists.linux-foundation.org, kernel-team@fb.com,
Matthew Wilcox <willy@infradead.org>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
Robin Murphy <robin.murphy@arm.com>,
Tony Lindgren <tony@atomide.com>
Subject: Re: [PATCH 10/10] dmapool: improve scalability of dma_pool_free
Date: Tue, 31 May 2022 15:54:23 -0600 [thread overview]
Message-ID: <YpaOj/C1SA8y1VCg@kbusch-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <801335ba-00f3-12ae-59e0-119d7d8fd8cd@cybernetics.com>
On Tue, May 31, 2022 at 02:23:44PM -0400, Tony Battersby wrote:
> dma_pool_free() scales poorly when the pool contains many pages because
> pool_find_page() does a linear scan of all allocated pages. Improve its
> scalability by replacing the linear scan with a red-black tree lookup.
> In big O notation, this improves the algorithm from O(n^2) to O(n * log n).
The improvement should say O(n) to O(log n), right?
WARNING: multiple messages have this Message-ID (diff)
From: Keith Busch <kbusch@kernel.org>
To: Tony Battersby <tonyb@cybernetics.com>
Cc: Tony Lindgren <tony@atomide.com>,
iommu@lists.linux-foundation.org,
Matthew Wilcox <willy@infradead.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andy Shevchenko <andy.shevchenko@gmail.com>,
kernel-team@fb.com, Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH 10/10] dmapool: improve scalability of dma_pool_free
Date: Tue, 31 May 2022 15:54:23 -0600 [thread overview]
Message-ID: <YpaOj/C1SA8y1VCg@kbusch-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <801335ba-00f3-12ae-59e0-119d7d8fd8cd@cybernetics.com>
On Tue, May 31, 2022 at 02:23:44PM -0400, Tony Battersby wrote:
> dma_pool_free() scales poorly when the pool contains many pages because
> pool_find_page() does a linear scan of all allocated pages. Improve its
> scalability by replacing the linear scan with a red-black tree lookup.
> In big O notation, this improves the algorithm from O(n^2) to O(n * log n).
The improvement should say O(n) to O(log n), right?
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next prev parent reply other threads:[~2022-05-31 21:54 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-31 18:11 [PATCH 00/10] mpt3sas and dmapool scalability Tony Battersby
2022-05-31 18:11 ` Tony Battersby
2022-05-31 18:12 ` [PATCH 01/10] dmapool: remove checks for dev == NULL Tony Battersby
2022-05-31 18:12 ` Tony Battersby
2022-05-31 18:23 ` Robin Murphy
2022-05-31 18:23 ` Robin Murphy
2022-05-31 18:13 ` [PATCH 02/10] dmapool: cleanup integer types Tony Battersby
2022-05-31 18:13 ` Tony Battersby
2022-05-31 18:14 ` [PATCH 03/10] dmapool: fix boundary comparison Tony Battersby
2022-05-31 18:14 ` Tony Battersby
2022-05-31 18:17 ` [PATCH 04/10] dmapool: improve accuracy of debug statistics Tony Battersby
2022-05-31 18:17 ` Tony Battersby
2022-05-31 19:48 ` Robin Murphy
2022-05-31 19:48 ` Robin Murphy
2022-05-31 19:52 ` Tony Battersby
2022-05-31 19:52 ` Tony Battersby
2022-05-31 21:55 ` Robin Murphy
2022-05-31 21:55 ` Robin Murphy
2022-05-31 18:18 ` [PATCH 05/10] dmapool: debug: prevent endless loop in case of corruption Tony Battersby
2022-05-31 18:18 ` Tony Battersby
2022-05-31 18:20 ` [PATCH 06/10] dmapool: ignore init_on_free when DMAPOOL_DEBUG enabled Tony Battersby
2022-05-31 18:20 ` Tony Battersby
2022-05-31 18:21 ` [PATCH 07/10] dmapool: speedup DMAPOOL_DEBUG with init_on_alloc Tony Battersby
2022-05-31 18:21 ` Tony Battersby
2022-05-31 18:22 ` [PATCH 08/10] dmapool: cleanup dma_pool_destroy Tony Battersby
2022-05-31 18:22 ` Tony Battersby
2022-05-31 19:33 ` Robin Murphy
2022-05-31 19:33 ` Robin Murphy
2022-05-31 21:40 ` Keith Busch
2022-05-31 21:40 ` Keith Busch
2022-05-31 18:23 ` [PATCH 09/10] dmapool: improve scalability of dma_pool_alloc Tony Battersby
2022-05-31 18:23 ` Tony Battersby
2022-05-31 18:23 ` [PATCH 10/10] dmapool: improve scalability of dma_pool_free Tony Battersby
2022-05-31 18:23 ` Tony Battersby
2022-05-31 21:54 ` Keith Busch [this message]
2022-05-31 21:54 ` Keith Busch
2022-05-31 22:10 ` Tony Battersby
2022-05-31 22:10 ` Tony Battersby
2022-06-01 9:44 ` Robin Murphy
2022-06-01 9:44 ` Robin Murphy
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