mm: mempolicy: Use _PAGE_NUMA to migrate pages

Note: Based on "mm/mpol: Use special PROT_NONE to migrate pages" but
	sufficiently different that the signed-off-bys were dropped

Combine our previous _PAGE_NUMA, mpol_misplaced and migrate_misplaced_page()
pieces into an effective migrate on fault scheme.

Note that (on x86) we rely on PROT_NONE pages being !present and avoid
the TLB flush from try_to_unmap(TTU_MIGRATION). This greatly improves the
page-migration performance.

Based-on-work-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
This commit is contained in:
Mel Gorman
2012-11-02 11:33:45 +00:00
parent 149c33e1c9
commit 4daae3b4b9
3 changed files with 60 additions and 12 deletions

View File

@@ -57,6 +57,7 @@
#include <linux/swapops.h>
#include <linux/elf.h>
#include <linux/gfp.h>
#include <linux/migrate.h>
#include <asm/io.h>
#include <asm/pgalloc.h>
@@ -3451,8 +3452,9 @@ static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, pte_t pte, pte_t *ptep, pmd_t *pmd)
{
struct page *page;
struct page *page = NULL;
spinlock_t *ptl;
int current_nid, target_nid;
/*
* The "pte" at this point cannot be used safely without
@@ -3465,8 +3467,11 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
*/
ptl = pte_lockptr(mm, pmd);
spin_lock(ptl);
if (unlikely(!pte_same(*ptep, pte)))
goto out_unlock;
if (unlikely(!pte_same(*ptep, pte))) {
pte_unmap_unlock(ptep, ptl);
goto out;
}
pte = pte_mknonnuma(pte);
set_pte_at(mm, addr, ptep, pte);
update_mmu_cache(vma, addr, ptep);
@@ -3477,8 +3482,25 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
return 0;
}
out_unlock:
get_page(page);
current_nid = page_to_nid(page);
target_nid = mpol_misplaced(page, vma, addr);
pte_unmap_unlock(ptep, ptl);
if (target_nid == -1) {
/*
* Account for the fault against the current node if it not
* being replaced regardless of where the page is located.
*/
current_nid = numa_node_id();
put_page(page);
goto out;
}
/* Migrate to the requested node */
if (migrate_misplaced_page(page, target_nid))
current_nid = target_nid;
out:
return 0;
}
@@ -3655,7 +3677,7 @@ retry:
barrier();
if (pmd_trans_huge(orig_pmd)) {
if (pmd_numa(*pmd))
return do_huge_pmd_numa_page(mm, address,
return do_huge_pmd_numa_page(mm, vma, address,
orig_pmd, pmd);
if ((flags & FAULT_FLAG_WRITE) && !pmd_write(orig_pmd)) {