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Revert "x86 PAT: remove CPA WARN_ON for zero pte" 

This reverts commit 58dab916df, which
makes my Nehalem come to a nasty crawling almost-halt.  It looks like it
turns off caching of regular kernel RAM, with the understandable
slowdown of a few orders of magnitude as a result.

Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2009-01-15 15:32:12 -08:00
parent 647df5189f
commit b5db0e3865
2 changed files with 17 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
arch/x86/mm/pageattr.c
View File

@ -555,12 +555,10 @@ static int __change_page_attr(struct cpa_data *cpa, int primary)
if (!pte_val(old_pte)) {
if (!primary)
return 0;
/*
* Special error value returned, indicating that the mapping
* did not exist at this address.
*/
return -EFAULT;
WARN(1, KERN_WARNING "CPA: called for zero pte. "
"vaddr = %lx cpa->vaddr = %lx\n", address,
*cpa->vaddr);
return -EINVAL;
}
if (level == PG_LEVEL_4K) {

45
arch/x86/mm/pat.c
View File

@ -505,35 +505,6 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size)
}
#endif /* CONFIG_STRICT_DEVMEM */
/*
* Change the memory type for the physial address range in kernel identity
* mapping space if that range is a part of identity map.
*/
static int kernel_map_sync_memtype(u64 base, unsigned long size,
unsigned long flags)
{
unsigned long id_sz;
int ret;
if (!pat_enabled || base >= __pa(high_memory))
return 0;
id_sz = (__pa(high_memory) < base + size) ?
__pa(high_memory) - base :
size;
ret = ioremap_change_attr((unsigned long)__va(base), id_sz, flags);
/*
* -EFAULT return means that the addr was not valid and did not have
* any identity mapping. That case is a success for
* kernel_map_sync_memtype.
*/
if (ret == -EFAULT)
ret = 0;
return ret;
}
int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
unsigned long size, pgprot_t *vma_prot)
{
@ -584,7 +555,9 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
if (retval < 0)
return 0;
if (kernel_map_sync_memtype(offset, size, flags)) {
if (((pfn < max_low_pfn_mapped) ||
(pfn >= (1UL<<(32 - PAGE_SHIFT)) && pfn < max_pfn_mapped)) &&
ioremap_change_attr((unsigned long)__va(offset), size, flags) < 0) {
free_memtype(offset, offset + size);
printk(KERN_INFO
"%s:%d /dev/mem ioremap_change_attr failed %s for %Lx-%Lx\n",
@ -632,7 +605,7 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
int strict_prot)
{
int is_ram = 0;
int ret;
int id_sz, ret;
unsigned long flags;
unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK);
@ -673,7 +646,15 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
flags);
}
if (kernel_map_sync_memtype(paddr, size, flags)) {
/* Need to keep identity mapping in sync */
if (paddr >= __pa(high_memory))
return 0;
id_sz = (__pa(high_memory) < paddr + size) ?
__pa(high_memory) - paddr :
size;
if (ioremap_change_attr((unsigned long)__va(paddr), id_sz, flags) < 0) {
free_memtype(paddr, paddr + size);
printk(KERN_ERR
"%s:%d reserve_pfn_range ioremap_change_attr failed %s "