> -----Original Message----- > From: Xen-devel [mailto:[email protected]] On Behalf > Of Joe Jin > Sent: 30 October 2018 02:52 > To: Boris Ostrovsky <[email protected]>; Konrad Rzeszutek Wilk > <[email protected]> > Cc: John Sobecki <[email protected]>; DONGLI.ZHANG > <[email protected]>; [email protected]" <linux- > [email protected]>; [email protected]; xen- > [email protected]; Christoph Helwig <[email protected]> > Subject: Re: [Xen-devel] [PATCH] xen-swiotlb: exchange memory with Xen > only when pages are contiguous > > On 10/25/18 11:56 AM, Joe Jin wrote: > > I just discussed this patch with Boris in private, his opinions(Boris, > > please correct me if any misunderstood) are: > > > > 1. With/without the check, both are incorrect, he thought we need to > > prevented unalloc'd free at here. > > 2. On freeing, if upper layer already checked the memory was DMA-able, > > the checking at here does not make sense, we can remove all checks. > > 3. xen_create_contiguous_region() and xen_destroy_contiguous_region() > > to come in pairs. > I tried to added radix_tree to track allocating/freeing and I found some > memory only allocated but was not freed, I guess it caused by driver used > dma_pool, that means if lots of such requests, the list will consume lot > of memory for it. Will continue to work on it, if anyone have good idea > for it please let me know, I'd like to try it. >
FWIW, in my Xen PV-IOMMU test patches, I have also tried keeping a list of ranges mapped for DMA and have discovered apparent issues with some drivers, particularly tg3, that seem to free mappings that have not been allocated (or possibly double-free). I've never fully tracked down the issue. Paul > Thanks, > Joe > > _______________________________________________ > Xen-devel mailing list > [email protected] > https://lists.xenproject.org/mailman/listinfo/xen-devel _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
