From: Christoph Hellwig <hch@lst.de>
To: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: amit.pundir@linaro.org, hch@lst.de, linux-kernel@vger.kernel.org,
Marek Szyprowski <m.szyprowski@samsung.com>,
Robin Murphy <robin.murphy@arm.com>,
rientjes@google.com, jeremy.linton@arm.com,
linux-rpi-kernel@lists.infradead.org,
iommu@lists.linux-foundation.org
Subject: Re: [PATCH v2 2/2] dma-pool: Only allocate from CMA when in same memory zone
Date: Tue, 4 Aug 2020 08:06:33 +0200 [thread overview]
Message-ID: <20200804060633.GA7368@lst.de> (raw)
In-Reply-To: <20200803160956.19235-3-nsaenzjulienne@suse.de>
On Mon, Aug 03, 2020 at 06:09:56PM +0200, Nicolas Saenz Julienne wrote:
> + if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA))
> + return end <= DMA_BIT_MASK(zone_dma_bits);
> + if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32))
> + return end <= DMA_BIT_MASK(32);
> + if (gfp & GFP_KERNEL)
> + return end > DMA_BIT_MASK(32);
So the GFP_KERNEL one here looks weird. For one I don't think the if
line is needed at all, and it just confuses things. Second I don't
see the need (and actually some harm) in preventing GFP_KERNEL
allocations from dipping into lower CMA areas - something that we did
support before 5.8 with the single pool.
next prev parent reply other threads:[~2020-08-04 6:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-03 16:09 [PATCH v2 0/2] dma-pool fixes Nicolas Saenz Julienne
2020-08-03 16:09 ` [PATCH v2 1/2] dma-pool: fix coherent pool allocations for IOMMU mappings Nicolas Saenz Julienne
2020-08-03 16:09 ` [PATCH v2 2/2] dma-pool: Only allocate from CMA when in same memory zone Nicolas Saenz Julienne
2020-08-04 6:06 ` Christoph Hellwig [this message]
2020-08-04 9:43 ` Nicolas Saenz Julienne
2020-08-06 5:18 ` Christoph Hellwig
2020-08-06 11:50 ` Nicolas Saenz Julienne
2020-08-06 13:55 ` Christoph Hellwig
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