xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

s390/mm: implement software referenced bits

Browse Source 
The last remaining use for the storage key of the s390 architecture
is reference counting. The alternative is to make page table entries
invalid while they are old. On access the fault handler marks the
pte/pmd as young which makes the pte/pmd valid if the access rights
allow read access. The pte/pmd invalidations required for software
managed reference bits cost a bit of performance, on the other hand
the RRBE/RRBM instructions to read and reset the referenced bits are
quite expensive as well.

Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky
2013-07-23 22:11:42 +02:00
parent fbd70035fb
commit 0944fe3f4a
7 changed files with 243 additions and 193 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
arch/s390/include/asm/page.h
View File

@@ -140,15 +140,6 @@ static inline int page_reset_referenced(unsigned long addr)
#define _PAGE_FP_BIT 0x08 /* HW fetch protection bit */
#define _PAGE_ACC_BITS 0xf0 /* HW access control bits */
/*
* Test and clear referenced bit in storage key.
*/
#define __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
static inline int page_test_and_clear_young(unsigned long pfn)
{
return page_reset_referenced(pfn << PAGE_SHIFT);
}
struct page;
void arch_free_page(struct page *page, int order);
void arch_alloc_page(struct page *page, int order);