Messages in this thread | | | From | "Wang, Xiaoming" <> | Subject | RE: [Xen-devel] [PATCH] modify the IO_TLB_SEGSIZE to io_tlb_segsize configurable as flexible requirement about SW-IOMMU. | Date | Wed, 11 Feb 2015 08:38:29 +0000 |
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Dear David
> -----Original Message----- > From: David Vrabel [mailto:david.vrabel@citrix.com] > Sent: Tuesday, February 10, 2015 5:46 PM > To: Wang, Xiaoming; Konrad Rzeszutek Wilk > Cc: linux-mips@linux-mips.org; pebolle@tiscali.nl; Zhang, Dongxing; > lauraa@codeaurora.org; d.kasatkin@samsung.com; > heiko.carstens@de.ibm.com; linux-kernel@vger.kernel.org; ralf@linux- > mips.org; chris@chris-wilson.co.uk; takahiro.akashi@linaro.org; > david.vrabel@citrix.com; linux@horizon.com; xen- > devel@lists.xenproject.org; boris.ostrovsky@oracle.com; Liu, Chuansheng; > akpm@linux-foundation.org > Subject: Re: [Xen-devel] [PATCH] modify the IO_TLB_SEGSIZE to > io_tlb_segsize configurable as flexible requirement about SW-IOMMU. > > On 06/02/15 00:10, Wang, Xiaoming wrote: > > > > > >> -----Original Message----- > >> From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@oracle.com] > >> Sent: Friday, February 6, 2015 3:33 AM > >> To: Wang, Xiaoming > >> Cc: ralf@linux-mips.org; boris.ostrovsky@oracle.com; > >> david.vrabel@citrix.com; linux-mips@linux-mips.org; linux- > >> kernel@vger.kernel.org; xen-devel@lists.xenproject.org; akpm@linux- > >> foundation.org; linux@horizon.com; lauraa@codeaurora.org; > >> heiko.carstens@de.ibm.com; d.kasatkin@samsung.com; > >> takahiro.akashi@linaro.org; chris@chris-wilson.co.uk; > >> pebolle@tiscali.nl; Liu, Chuansheng; Zhang, Dongxing > >> Subject: Re: [PATCH] modify the IO_TLB_SEGSIZE to io_tlb_segsize > >> configurable as flexible requirement about SW-IOMMU. > >> > >> On Fri, Feb 06, 2015 at 07:01:14AM +0800, xiaomin1 wrote: > >>> The maximum of SW-IOMMU is limited to 2^11*128 = 256K. > >>> While in different platform and different requirements this seems > improper. > >>> So modify the IO_TLB_SEGSIZE to io_tlb_segsize as configurable is > >>> make > >> sense. > >> > >> More details please. What is the issue you are hitting? > >> > > Example: > > If 1M bytes are requied. There has an error like. > > Instead of allowing the bouncing of such large buffers, could the gadget > driver be modified to submit the buffers to the hardware in smaller chunks? > > David
Our target is try to make IO_TLB_SEGSIZE configurable. Neither 256 bytes or 1M bytes seems suitable value, I think. It's better to use the tactics something like kmem_cache_create in kmalloc function. But SW-IOMMU seems more lighter. So we choose variable rather than function.
Xiaoming.
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