[PATCH v6 5/5] mm: factor out common parts between MADV_COLD and MADV_PAGEOUT

Minchan Kim
2019-07-23T06:26:20Z

There are many common parts between MADV_COLD and MADV_PAGEOUT.
This patch factor them out to save code duplication.

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
mm/madvise.c | 193 ++++++++++++---------------------------------------
1 file changed, 46 insertions(+), 147 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 24ded9f9e0fab..22be197c7cc9b 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -30,6 +30,11 @@

#include "internal.h"

+struct madvise_walk_private {
+ struct mmu_gather *tlb;
+ bool pageout;
+};
+
/*
* Any behaviour which results in changes to the vma->vm_flags needs to
* take mmap_sem for writing. Others, which simply traverse vmas, need
@@ -310,16 +315,23 @@ static long madvise_willneed(struct vm_area_struct *vma,
return 0;
}

-static int madvise_cold_pte_range(pmd_t *pmd, unsigned long addr,
- unsigned long end, struct mm_walk *walk)
+static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
+ unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
{
- struct mmu_gather *tlb = walk->private;
+ struct madvise_walk_private *private = walk->private;
+ struct mmu_gather *tlb = private->tlb;
+ bool pageout = private->pageout;
struct mm_struct *mm = tlb->mm;
struct vm_area_struct *vma = walk->vma;
pte_t *orig_pte, *pte, ptent;
spinlock_t *ptl;
- struct page *page;
unsigned long next;
+ struct page *page = NULL;
+ LIST_HEAD(page_list);
+
+ if (fatal_signal_pending(current))
+ return -EINTR;

next = pmd_addr_end(addr, end);
if (pmd_trans_huge(*pmd)) {
@@ -366,10 +378,17 @@ static int madvise_cold_pte_range(pmd_t *pmd, unsigned long addr,
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
}

+ ClearPageReferenced(page);
test_and_clear_page_young(page);
- deactivate_page(page);
+ if (pageout) {
+ if (!isolate_lru_page(page))
+ list_add(&page->lru, &page_list);
+ } else
+ deactivate_page(page);
huge_unlock:
spin_unlock(ptl);
+ if (pageout)
+ reclaim_pages(&page_list);
return 0;
}

@@ -437,12 +456,19 @@ static int madvise_cold_pte_range(pmd_t *pmd, unsigned long addr,
* As a side effect, it makes confuse idle-page tracking
* because they will miss recent referenced history.
*/
+ ClearPageReferenced(page);
test_and_clear_page_young(page);
- deactivate_page(page);
+ if (pageout) {
+ if (!isolate_lru_page(page))
+ list_add(&page->lru, &page_list);
+ } else
+ deactivate_page(page);
}

arch_leave_lazy_mmu_mode();
pte_unmap_unlock(orig_pte, ptl);
+ if (pageout)
+ reclaim_pages(&page_list);
cond_resched();

return 0;
@@ -452,10 +478,15 @@ static void madvise_cold_page_range(struct mmu_gather *tlb,
struct vm_area_struct *vma,
unsigned long addr, unsigned long end)
{
+ struct madvise_walk_private walk_private = {
+ .tlb = tlb,
+ .pageout = false,
+ };
+
struct mm_walk cold_walk = {
- .pmd_entry = madvise_cold_pte_range,
+ .pmd_entry = madvise_cold_or_pageout_pte_range,
.mm = vma->vm_mm,
- .private = tlb,
+ .private = &walk_private,
};

tlb_start_vma(tlb, vma);
@@ -482,151 +513,19 @@ static long madvise_cold(struct vm_area_struct *vma,
return 0;
}

-static int madvise_pageout_pte_range(pmd_t *pmd, unsigned long addr,
- unsigned long end, struct mm_walk *walk)
-{
- struct mmu_gather *tlb = walk->private;
- struct mm_struct *mm = tlb->mm;
- struct vm_area_struct *vma = walk->vma;
- pte_t *orig_pte, *pte, ptent;
- spinlock_t *ptl;
- LIST_HEAD(page_list);
- struct page *page;
- unsigned long next;
-
- if (fatal_signal_pending(current))
- return -EINTR;
-
- next = pmd_addr_end(addr, end);
- if (pmd_trans_huge(*pmd)) {
- pmd_t orig_pmd;
-
- tlb_change_page_size(tlb, HPAGE_PMD_SIZE);
- ptl = pmd_trans_huge_lock(pmd, vma);
- if (!ptl)
- return 0;
-
- orig_pmd = *pmd;
- if (is_huge_zero_pmd(orig_pmd))
- goto huge_unlock;
-
- if (unlikely(!pmd_present(orig_pmd))) {
- VM_BUG_ON(thp_migration_supported() &&
- !is_pmd_migration_entry(orig_pmd));
- goto huge_unlock;
- }
-
- page = pmd_page(orig_pmd);
- if (next - addr != HPAGE_PMD_SIZE) {
- int err;
-
- if (page_mapcount(page) != 1)
- goto huge_unlock;
- get_page(page);
- spin_unlock(ptl);
- lock_page(page);
- err = split_huge_page(page);
- unlock_page(page);
- put_page(page);
- if (!err)
- goto regular_page;
- return 0;
- }
-
- if (pmd_young(orig_pmd)) {
- pmdp_invalidate(vma, addr, pmd);
- orig_pmd = pmd_mkold(orig_pmd);
-
- set_pmd_at(mm, addr, pmd, orig_pmd);
- tlb_remove_tlb_entry(tlb, pmd, addr);
- }
-
- ClearPageReferenced(page);
- test_and_clear_page_young(page);
-
- if (!isolate_lru_page(page))
- list_add(&page->lru, &page_list);
-huge_unlock:
- spin_unlock(ptl);
- reclaim_pages(&page_list);
- return 0;
- }
-
- if (pmd_trans_unstable(pmd))
- return 0;
-regular_page:
- tlb_change_page_size(tlb, PAGE_SIZE);
- orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
- flush_tlb_batched_pending(mm);
- arch_enter_lazy_mmu_mode();
- for (; addr < end; pte++, addr += PAGE_SIZE) {
- ptent = *pte;
- if (!pte_present(ptent))
- continue;
-
- page = vm_normal_page(vma, addr, ptent);
- if (!page)
- continue;
-
- /*
- * creating a THP page is expensive so split it only if we
- * are sure it's worth. Split it if we are only owner.
- */
- if (PageTransCompound(page)) {
- if (page_mapcount(page) != 1)
- break;
- get_page(page);
- if (!trylock_page(page)) {
- put_page(page);
- break;
- }
- pte_unmap_unlock(orig_pte, ptl);
- if (split_huge_page(page)) {
- unlock_page(page);
- put_page(page);
- pte_offset_map_lock(mm, pmd, addr, &ptl);
- break;
- }
- unlock_page(page);
- put_page(page);
- pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
- pte--;
- addr -= PAGE_SIZE;
- continue;
- }
-
- VM_BUG_ON_PAGE(PageTransCompound(page), page);
-
- if (pte_young(ptent)) {
- ptent = ptep_get_and_clear_full(mm, addr, pte,
- tlb->fullmm);
- ptent = pte_mkold(ptent);
- set_pte_at(mm, addr, pte, ptent);
- tlb_remove_tlb_entry(tlb, pte, addr);
- }
- ClearPageReferenced(page);
- test_and_clear_page_young(page);
-
- if (!isolate_lru_page(page))
- list_add(&page->lru, &page_list);
- }
-
- arch_leave_lazy_mmu_mode();
- pte_unmap_unlock(orig_pte, ptl);
- reclaim_pages(&page_list);
- cond_resched();
-
- return 0;
-}
-
static void madvise_pageout_page_range(struct mmu_gather *tlb,
struct vm_area_struct *vma,
unsigned long addr, unsigned long end)
{
+ struct madvise_walk_private walk_private = {
+ .pageout = true,
+ .tlb = tlb,
+ };
+
struct mm_walk pageout_walk = {
- .pmd_entry = madvise_pageout_pte_range,
+ .pmd_entry = madvise_cold_or_pageout_pte_range,
.mm = vma->vm_mm,
- .private = tlb,
+ .private = &walk_private,
};

tlb_start_vma(tlb, vma);
--
2.22.0.657.g960e92d24f-goog