lkml.org 
[lkml]   [2015]   [Oct]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCHv12 30/37] thp: add option to setup migration entries during PMD split
Date
We are going to use migration PTE entries to stabilize page counts.
If the page is mapped with PMDs we need to split the PMD and setup
migration entries. It's reasonable to combine these operations to avoid
double-scanning over the page table.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
---
mm/huge_memory.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index d2a86df4dd00..4a2a263790b2 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2806,7 +2806,7 @@ static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
}

static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
- unsigned long haddr)
+ unsigned long haddr, bool freeze)
{
struct mm_struct *mm = vma->vm_mm;
struct page *page;
@@ -2850,12 +2850,18 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
* transferred to avoid any possibility of altering
* permissions across VMAs.
*/
- entry = mk_pte(page + i, vma->vm_page_prot);
- entry = maybe_mkwrite(pte_mkdirty(entry), vma);
- if (!write)
- entry = pte_wrprotect(entry);
- if (!young)
- entry = pte_mkold(entry);
+ if (freeze) {
+ swp_entry_t swp_entry;
+ swp_entry = make_migration_entry(page + i, write);
+ entry = swp_entry_to_pte(swp_entry);
+ } else {
+ entry = mk_pte(page + i, vma->vm_page_prot);
+ entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+ if (!write)
+ entry = pte_wrprotect(entry);
+ if (!young)
+ entry = pte_mkold(entry);
+ }
pte = pte_offset_map(&_pmd, haddr);
BUG_ON(!pte_none(*pte));
set_pte_at(mm, haddr, pte, entry);
@@ -2896,7 +2902,7 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PMD_SIZE);
ptl = pmd_lock(mm, pmd);
if (likely(pmd_trans_huge(*pmd)))
- __split_huge_pmd_locked(vma, pmd, haddr);
+ __split_huge_pmd_locked(vma, pmd, haddr, false);
spin_unlock(ptl);
mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PMD_SIZE);
}
--
2.5.3


\
 
 \ /
  Last update: 2015-10-06 17:41    [W:0.115 / U:0.500 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site