From: Christoph Hellwig <hch@infradead.org>
To: Brian Johannesmeyer <bjohannesmeyer@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org,
Raphael Isemann <teemperor@gmail.com>,
Cristiano Giuffrida <giuffrida@cs.vu.nl>,
Herbert Bos <h.j.bos@vu.nl>, Greg KH <gregkh@linuxfoundation.org>,
Keith Busch <kbusch@kernel.org>
Subject: Re: [RFC v2 1/2] dmapool: Move pool metadata into non-DMA memory
Date: Wed, 20 Nov 2024 01:37:17 -0800 [thread overview]
Message-ID: <Zz2tzVqql2RMSFN4@infradead.org> (raw)
In-Reply-To: <20241119205529.3871048-2-bjohannesmeyer@gmail.com>
On Tue, Nov 19, 2024 at 09:55:28PM +0100, Brian Johannesmeyer wrote:
> + page->blocks_per_page = pool->allocation / pool->size;
> + page->blocks = kmalloc_array(page->blocks_per_page,
> + sizeof(struct dma_block), GFP_KERNEL);
Given that you now need an array of the blocks anyway, it might make
sense to switch from a linked list to a bitmap for tracking free state,
which would be a lot more efficient as you only need a bit per block
as tracking overhead instead of a two pointers and a dma_addr_t.
e.g. do a find_first_zero_bit() to find the ffree slot, then calculate
the dma_addr and virt address by simple offseting into the dma_page
ones with bitnr * pool->size.
next prev parent reply other threads:[~2024-11-20 9:37 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-19 20:55 [RFC v2 0/2] dmapool: Mitigate device-controllable mem. corruption Brian Johannesmeyer
2024-11-19 20:55 ` [RFC v2 1/2] dmapool: Move pool metadata into non-DMA memory Brian Johannesmeyer
2024-11-20 9:37 ` Christoph Hellwig [this message]
2024-11-20 23:46 ` Brian Johannesmeyer
2024-11-21 5:03 ` Christoph Hellwig
2024-11-21 17:48 ` Brian Johannesmeyer
2024-11-19 20:55 ` [RFC v2 2/2] dmapool: Use pool_find_block() in pool_block_err() Brian Johannesmeyer
2024-11-19 22:14 ` [RFC v2 0/2] dmapool: Mitigate device-controllable mem. corruption Greg KH
2024-11-19 22:22 ` Brian Johannesmeyer
2024-11-20 9:29 ` Christoph Hellwig
2024-11-20 15:56 ` Keith Busch
2024-11-20 18:51 ` Keith Busch
2024-11-20 21:58 ` Brian Johannesmeyer
2024-11-21 3:37 ` Keith Busch
2024-11-21 17:31 ` Brian Johannesmeyer
2024-11-21 18:06 ` Keith Busch
2024-11-21 19:07 ` Brian Johannesmeyer
2024-11-22 19:19 ` Brian Johannesmeyer
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