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Commit b877ac98 authored by Juergen Gross's avatar Juergen Gross
Browse files

xen/swiotlb: remember having called xen_create_contiguous_region() 



Instead of always calling xen_destroy_contiguous_region() in case the
memory is DMA-able for the used device, do so only in case it has been
made DMA-able via xen_create_contiguous_region() before.

This will avoid a lot of xen_destroy_contiguous_region() calls for
64-bit capable devices.

As the memory in question is owned by swiotlb-xen the PG_owner_priv_1
flag of the first allocated page can be used for remembering.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Acked-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent bf707266

drivers/xen/swiotlb-xen.c

+3 −1
Original line number Diff line number Diff line
@@ -322,6 +322,7 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size, 
			xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs);

			return NULL;

		}

		SetPageXenRemapped(virt_to_page(ret));

	}

	memset(ret, 0, size);

	return ret;
@@ -346,7 +347,8 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr, 
	size = 1UL << (order + XEN_PAGE_SHIFT);



	if (!WARN_ON((dev_addr + size - 1 > dma_mask) ||

		     range_straddles_page_boundary(phys, size)))

		     range_straddles_page_boundary(phys, size)) &&

	    TestClearPageXenRemapped(virt_to_page(vaddr)))

		xen_destroy_contiguous_region(phys, order);



	xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);

include/linux/page-flags.h

+4 −0
Original line number Diff line number Diff line
@@ -152,6 +152,8 @@ enum pageflags { 
	PG_savepinned = PG_dirty,

	/* Has a grant mapping of another (foreign) domain's page. */

	PG_foreign = PG_owner_priv_1,

	/* Remapped by swiotlb-xen. */

	PG_xen_remapped = PG_owner_priv_1,



	/* SLOB */

	PG_slob_free = PG_private,
@@ -329,6 +331,8 @@ PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND) 
	TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)

PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);

PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);

PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)

	TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)



PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)

	__CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)