From: Tony Battersby <tonyb@cybernetics.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Sathya Prakash <sathya.prakash@broadcom.com>,
Chaitra P B <chaitra.basappa@broadcom.com>,
Suganath Prabu Subramani <suganath-prabu.subramani@broadcom.com>,
iommu@lists.linux-foundation.org, linux-mm@kvack.org,
linux-scsi@vger.kernel.org, MPT-FusionLinux.pdl@broadcom.com
Subject: Re: [PATCH v2 8/9] dmapool: reduce footprint in struct page
Date: Fri, 3 Aug 2018 10:04:44 -0400 [thread overview]
Message-ID: <37abe59f-70cb-d125-b87f-49f63de6ece7@cybernetics.com> (raw)
In-Reply-To: <20180802235626.GA5773@bombadil.infradead.org>
On 08/02/2018 07:56 PM, Matthew Wilcox wrote:
>
>> One of the nice things about this is that dma_pool_free() can do some
>> additional sanity checks:
>> *) Check that the offset of the passed-in address corresponds to a valid
>> block offset.
> Can't we do that already? Subtract the base address of the page from
> the passed-in vaddr and check it's a multiple of pool->size?
The gaps caused by 'boundary' make it a lot more complicated than that.A
See pool_offset_to_blk_idx().A Your suggestion is the fast-path top part
of pool_offset_to_blk_idx() where dma_pool_create() set
blks_per_boundary to 0 to get a speed boost.A The ugly slow case to take
the boundary into account is the bottom part of pool_offset_to_blk_idx().
next prev parent reply other threads:[~2018-08-03 14:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-02 20:01 Tony Battersby
2018-08-02 23:56 ` Matthew Wilcox
2018-08-03 14:04 ` Tony Battersby [this message]
2018-08-03 14:49 ` Tony Battersby
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