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Commit 4b065046 authored by Pallipadi, Venkatesh's avatar Pallipadi, Venkatesh Committed by Ingo Molnar
Browse files

x86, PAT: Remove page granularity tracking for vm_insert_pfn maps 

This change resolves the problem of too many single page entries
in pat_memtype_list and "freeing invalid memtype" errors with i915,
reported here:

  http://marc.info/?l=linux-kernel&m=123845244713183&w=2



Remove page level granularity track and untrack of vm_insert_pfn.
memtype tracking at page granularity does not scale and cleaner
approach would be for the driver to request a type for a bigger
IO address range or PCI io memory range for that device, either at
mmap time or driver init time and just use that type during
vm_insert_pfn.

This patch just removes the track/untrack of vm_insert_pfn. That
means we will be in same state as 2.6.28, with respect to these APIs.

Newer APIs for the drivers to request a memtype for a bigger region
is coming soon.

[ Impact: fix Xorg startup warnings and hangs ]

Reported-by: default avatarArkadiusz Miskiewicz <a.miskiewicz@gmail.com>
Tested-by: default avatarArkadiusz Miskiewicz <a.miskiewicz@gmail.com>
Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
LKML-Reference: <20090408223716.GC3493@linux-os.sc.intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent d45b41ae

arch/x86/mm/pat.c

+19 −79
Original line number Diff line number Diff line
@@ -669,29 +669,28 @@ static void free_pfn_range(u64 paddr, unsigned long size) 
 *

 * If the vma has a linear pfn mapping for the entire range, we get the prot

 * from pte and reserve the entire vma range with single reserve_pfn_range call.

 * Otherwise, we reserve the entire vma range, my ging through the PTEs page

 * by page to get physical address and protection.

 */

int track_pfn_vma_copy(struct vm_area_struct *vma)

{

	int retval = 0;

	unsigned long i, j;

	resource_size_t paddr;

	unsigned long prot;

	unsigned long vma_start = vma->vm_start;

	unsigned long vma_end = vma->vm_end;

	unsigned long vma_size = vma_end - vma_start;

	unsigned long vma_size = vma->vm_end - vma->vm_start;

	pgprot_t pgprot;



	if (!pat_enabled)

		return 0;



	/*

	 * For now, only handle remap_pfn_range() vmas where

	 * is_linear_pfn_mapping() == TRUE. Handling of

	 * vm_insert_pfn() is TBD.

	 */

	if (is_linear_pfn_mapping(vma)) {

		/*

		 * reserve the whole chunk covered by vma. We need the

		 * starting address and protection from pte.

		 */

		if (follow_phys(vma, vma_start, 0, &prot, &paddr)) {

		if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {

			WARN_ON_ONCE(1);

			return -EINVAL;

		}
@@ -699,28 +698,7 @@ int track_pfn_vma_copy(struct vm_area_struct *vma) 
		return reserve_pfn_range(paddr, vma_size, &pgprot, 1);

	}



	/* reserve entire vma page by page, using pfn and prot from pte */

	for (i = 0; i < vma_size; i += PAGE_SIZE) {

		if (follow_phys(vma, vma_start + i, 0, &prot, &paddr))

			continue;



		pgprot = __pgprot(prot);

		retval = reserve_pfn_range(paddr, PAGE_SIZE, &pgprot, 1);

		if (retval)

			goto cleanup_ret;

	}

	return 0;



cleanup_ret:

	/* Reserve error: Cleanup partial reservation and return error */

	for (j = 0; j < i; j += PAGE_SIZE) {

		if (follow_phys(vma, vma_start + j, 0, &prot, &paddr))

			continue;



		free_pfn_range(paddr, PAGE_SIZE);

	}



	return retval;

}



/*
@@ -730,50 +708,28 @@ int track_pfn_vma_copy(struct vm_area_struct *vma) 
 * prot is passed in as a parameter for the new mapping. If the vma has a

 * linear pfn mapping for the entire range reserve the entire vma range with

 * single reserve_pfn_range call.

 * Otherwise, we look t the pfn and size and reserve only the specified range

 * page by page.

 *

 * Note that this function can be called with caller trying to map only a

 * subrange/page inside the vma.

 */

int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,

			unsigned long pfn, unsigned long size)

{

	int retval = 0;

	unsigned long i, j;

	resource_size_t base_paddr;

	resource_size_t paddr;

	unsigned long vma_start = vma->vm_start;

	unsigned long vma_end = vma->vm_end;

	unsigned long vma_size = vma_end - vma_start;

	unsigned long vma_size = vma->vm_end - vma->vm_start;



	if (!pat_enabled)

		return 0;



	/*

	 * For now, only handle remap_pfn_range() vmas where

	 * is_linear_pfn_mapping() == TRUE. Handling of

	 * vm_insert_pfn() is TBD.

	 */

	if (is_linear_pfn_mapping(vma)) {

		/* reserve the whole chunk starting from vm_pgoff */

		paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;

		return reserve_pfn_range(paddr, vma_size, prot, 0);

	}



	/* reserve page by page using pfn and size */

	base_paddr = (resource_size_t)pfn << PAGE_SHIFT;

	for (i = 0; i < size; i += PAGE_SIZE) {

		paddr = base_paddr + i;

		retval = reserve_pfn_range(paddr, PAGE_SIZE, prot, 0);

		if (retval)

			goto cleanup_ret;

	}

	return 0;



cleanup_ret:

	/* Reserve error: Cleanup partial reservation and return error */

	for (j = 0; j < i; j += PAGE_SIZE) {

		paddr = base_paddr + j;

		free_pfn_range(paddr, PAGE_SIZE);

	}



	return retval;

}



/*
@@ -784,39 +740,23 @@ int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot, 
void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,

			unsigned long size)

{

	unsigned long i;

	resource_size_t paddr;

	unsigned long prot;

	unsigned long vma_start = vma->vm_start;

	unsigned long vma_end = vma->vm_end;

	unsigned long vma_size = vma_end - vma_start;

	unsigned long vma_size = vma->vm_end - vma->vm_start;



	if (!pat_enabled)

		return;



	/*

	 * For now, only handle remap_pfn_range() vmas where

	 * is_linear_pfn_mapping() == TRUE. Handling of

	 * vm_insert_pfn() is TBD.

	 */

	if (is_linear_pfn_mapping(vma)) {

		/* free the whole chunk starting from vm_pgoff */

		paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;

		free_pfn_range(paddr, vma_size);

		return;

	}



	if (size != 0 && size != vma_size) {

		/* free page by page, using pfn and size */

		paddr = (resource_size_t)pfn << PAGE_SHIFT;

		for (i = 0; i < size; i += PAGE_SIZE) {

			paddr = paddr + i;

			free_pfn_range(paddr, PAGE_SIZE);

		}

	} else {

		/* free entire vma, page by page, using the pfn from pte */

		for (i = 0; i < vma_size; i += PAGE_SIZE) {

			if (follow_phys(vma, vma_start + i, 0, &prot, &paddr))

				continue;



			free_pfn_range(paddr, PAGE_SIZE);

		}

	}

}



pgprot_t pgprot_writecombine(pgprot_t prot)