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Message-Id: <20170124162824.91275-8-kirill.shutemov@linux.intel.com>
Date: Tue, 24 Jan 2017 19:28:19 +0300
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: Andrea Arcangeli <aarcange@...hat.com>,
Hugh Dickins <hughd@...gle.com>,
Rik van Riel <riel@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCH 07/12] mm: convert try_to_unmap_one() to page_check_walk()
For consistency, it worth converting all page_check_address() to
page_check_walk(), so we could drop the former.
It also makes freeze_page() as we walk though rmap only once.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
---
mm/huge_memory.c | 16 +---
mm/rmap.c | 260 ++++++++++++++++++++++++++++---------------------------
2 files changed, 137 insertions(+), 139 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 16820e001d79..ca7855f857fa 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1839,24 +1839,16 @@ void vma_adjust_trans_huge(struct vm_area_struct *vma,
static void freeze_page(struct page *page)
{
enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS |
- TTU_RMAP_LOCKED;
- int i, ret;
+ TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD;
+ int ret;
VM_BUG_ON_PAGE(!PageHead(page), page);
if (PageAnon(page))
ttu_flags |= TTU_MIGRATION;
- /* We only need TTU_SPLIT_HUGE_PMD once */
- ret = try_to_unmap(page, ttu_flags | TTU_SPLIT_HUGE_PMD);
- for (i = 1; !ret && i < HPAGE_PMD_NR; i++) {
- /* Cut short if the page is unmapped */
- if (page_count(page) == 1)
- return;
-
- ret = try_to_unmap(page + i, ttu_flags);
- }
- VM_BUG_ON_PAGE(ret, page + i - 1);
+ ret = try_to_unmap(page, ttu_flags);
+ VM_BUG_ON_PAGE(ret, page);
}
static void unfreeze_page(struct page *page)
diff --git a/mm/rmap.c b/mm/rmap.c
index 41874a6f6cf5..c9a096ffb242 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -607,8 +607,7 @@ void try_to_unmap_flush_dirty(void)
try_to_unmap_flush();
}
-static void set_tlb_ubc_flush_pending(struct mm_struct *mm,
- struct page *page, bool writable)
+static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable)
{
struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc;
@@ -643,8 +642,7 @@ static bool should_defer_flush(struct mm_struct *mm, enum ttu_flags flags)
return should_defer;
}
#else
-static void set_tlb_ubc_flush_pending(struct mm_struct *mm,
- struct page *page, bool writable)
+static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable)
{
}
@@ -1457,155 +1455,163 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
unsigned long address, void *arg)
{
struct mm_struct *mm = vma->vm_mm;
- pte_t *pte;
+ struct page_check_walk pcw = {
+ .page = page,
+ .vma = vma,
+ .address = address,
+ };
pte_t pteval;
- spinlock_t *ptl;
+ struct page *subpage;
int ret = SWAP_AGAIN;
struct rmap_private *rp = arg;
enum ttu_flags flags = rp->flags;
/* munlock has nothing to gain from examining un-locked vmas */
if ((flags & TTU_MUNLOCK) && !(vma->vm_flags & VM_LOCKED))
- goto out;
+ return SWAP_AGAIN;
if (flags & TTU_SPLIT_HUGE_PMD) {
split_huge_pmd_address(vma, address,
flags & TTU_MIGRATION, page);
- /* check if we have anything to do after split */
- if (page_mapcount(page) == 0)
- goto out;
}
- pte = page_check_address(page, mm, address, &ptl,
- PageTransCompound(page));
- if (!pte)
- goto out;
+ while (page_check_walk(&pcw)) {
+ subpage = page - page_to_pfn(page) + pte_pfn(*pcw.pte);
+ address = pcw.address;
- /*
- * If the page is mlock()d, we cannot swap it out.
- * If it's recently referenced (perhaps page_referenced
- * skipped over this mm) then we should reactivate it.
- */
- if (!(flags & TTU_IGNORE_MLOCK)) {
- if (vma->vm_flags & VM_LOCKED) {
- /* PTE-mapped THP are never mlocked */
- if (!PageTransCompound(page)) {
- /*
- * Holding pte lock, we do *not* need
- * mmap_sem here
- */
- mlock_vma_page(page);
+ /* Unexpected PMD-mapped THP? */
+ VM_BUG_ON_PAGE(!pcw.pte, page);
+
+ /*
+ * If the page is mlock()d, we cannot swap it out.
+ * If it's recently referenced (perhaps page_referenced
+ * skipped over this mm) then we should reactivate it.
+ */
+ if (!(flags & TTU_IGNORE_MLOCK)) {
+ if (vma->vm_flags & VM_LOCKED) {
+ /* PTE-mapped THP are never mlocked */
+ if (!PageTransCompound(page)) {
+ /*
+ * Holding pte lock, we do *not* need
+ * mmap_sem here
+ */
+ mlock_vma_page(page);
+ }
+ ret = SWAP_MLOCK;
+ page_check_walk_done(&pcw);
+ break;
}
- ret = SWAP_MLOCK;
- goto out_unmap;
+ if (flags & TTU_MUNLOCK)
+ continue;
}
- if (flags & TTU_MUNLOCK)
- goto out_unmap;
- }
- if (!(flags & TTU_IGNORE_ACCESS)) {
- if (ptep_clear_flush_young_notify(vma, address, pte)) {
- ret = SWAP_FAIL;
- goto out_unmap;
+
+ if (!(flags & TTU_IGNORE_ACCESS)) {
+ if (ptep_clear_flush_young_notify(vma, address,
+ pcw.pte)) {
+ ret = SWAP_FAIL;
+ page_check_walk_done(&pcw);
+ break;
+ }
}
- }
- /* Nuke the page table entry. */
- flush_cache_page(vma, address, page_to_pfn(page));
- if (should_defer_flush(mm, flags)) {
- /*
- * We clear the PTE but do not flush so potentially a remote
- * CPU could still be writing to the page. If the entry was
- * previously clean then the architecture must guarantee that
- * a clear->dirty transition on a cached TLB entry is written
- * through and traps if the PTE is unmapped.
- */
- pteval = ptep_get_and_clear(mm, address, pte);
+ /* Nuke the page table entry. */
+ flush_cache_page(vma, address, pte_to_pfn(pcw.pte));
+ if (should_defer_flush(mm, flags)) {
+ /*
+ * We clear the PTE but do not flush so potentially
+ * a remote CPU could still be writing to the page.
+ * If the entry was previously clean then the
+ * architecture must guarantee that a clear->dirty
+ * transition on a cached TLB entry is written through
+ * and traps if the PTE is unmapped.
+ */
+ pteval = ptep_get_and_clear(mm, address, pcw.pte);
+
+ set_tlb_ubc_flush_pending(mm, pte_dirty(pteval));
+ } else {
+ pteval = ptep_clear_flush(vma, address, pcw.pte);
+ }
- set_tlb_ubc_flush_pending(mm, page, pte_dirty(pteval));
- } else {
- pteval = ptep_clear_flush(vma, address, pte);
- }
+ /* Move the dirty bit to the page. Now the pte is gone. */
+ if (pte_dirty(pteval))
+ set_page_dirty(page);
- /* Move the dirty bit to the physical page now the pte is gone. */
- if (pte_dirty(pteval))
- set_page_dirty(page);
+ /* Update high watermark before we lower rss */
+ update_hiwater_rss(mm);
- /* Update high watermark before we lower rss */
- update_hiwater_rss(mm);
+ if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) {
+ if (PageHuge(page)) {
+ int nr = 1 << compound_order(page);
+ hugetlb_count_sub(nr, mm);
+ } else {
+ dec_mm_counter(mm, mm_counter(page));
+ }
- if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) {
- if (PageHuge(page)) {
- hugetlb_count_sub(1 << compound_order(page), mm);
- } else {
+ pteval = swp_entry_to_pte(make_hwpoison_entry(subpage));
+ set_pte_at(mm, address, pcw.pte, pteval);
+ } else if (pte_unused(pteval)) {
+ /*
+ * The guest indicated that the page content is of no
+ * interest anymore. Simply discard the pte, vmscan
+ * will take care of the rest.
+ */
dec_mm_counter(mm, mm_counter(page));
- }
- set_pte_at(mm, address, pte,
- swp_entry_to_pte(make_hwpoison_entry(page)));
- } else if (pte_unused(pteval)) {
- /*
- * The guest indicated that the page content is of no
- * interest anymore. Simply discard the pte, vmscan
- * will take care of the rest.
- */
- dec_mm_counter(mm, mm_counter(page));
- } else if (IS_ENABLED(CONFIG_MIGRATION) && (flags & TTU_MIGRATION)) {
- swp_entry_t entry;
- pte_t swp_pte;
- /*
- * Store the pfn of the page in a special migration
- * pte. do_swap_page() will wait until the migration
- * pte is removed and then restart fault handling.
- */
- entry = make_migration_entry(page, pte_write(pteval));
- swp_pte = swp_entry_to_pte(entry);
- if (pte_soft_dirty(pteval))
- swp_pte = pte_swp_mksoft_dirty(swp_pte);
- set_pte_at(mm, address, pte, swp_pte);
- } else if (PageAnon(page)) {
- swp_entry_t entry = { .val = page_private(page) };
- pte_t swp_pte;
- /*
- * Store the swap location in the pte.
- * See handle_pte_fault() ...
- */
- VM_BUG_ON_PAGE(!PageSwapCache(page), page);
+ } else if (IS_ENABLED(CONFIG_MIGRATION) &&
+ (flags & TTU_MIGRATION)) {
+ swp_entry_t entry;
+ pte_t swp_pte;
+ /*
+ * Store the pfn of the page in a special migration
+ * pte. do_swap_page() will wait until the migration
+ * pte is removed and then restart fault handling.
+ */
+ entry = make_migration_entry(subpage,
+ pte_write(pteval));
+ swp_pte = swp_entry_to_pte(entry);
+ if (pte_soft_dirty(pteval))
+ swp_pte = pte_swp_mksoft_dirty(swp_pte);
+ set_pte_at(mm, address, pcw.pte, swp_pte);
+ } else if (PageAnon(page)) {
+ swp_entry_t entry = { .val = page_private(subpage) };
+ pte_t swp_pte;
+ /*
+ * Store the swap location in the pte.
+ * See handle_pte_fault() ...
+ */
+ VM_BUG_ON_PAGE(!PageSwapCache(page), page);
+
+ if (!PageDirty(page) && (flags & TTU_LZFREE)) {
+ /* It's a freeable page by MADV_FREE */
+ dec_mm_counter(mm, MM_ANONPAGES);
+ rp->lazyfreed++;
+ goto discard;
+ }
- if (!PageDirty(page) && (flags & TTU_LZFREE)) {
- /* It's a freeable page by MADV_FREE */
+ if (swap_duplicate(entry) < 0) {
+ set_pte_at(mm, address, pcw.pte, pteval);
+ ret = SWAP_FAIL;
+ page_check_walk_done(&pcw);
+ break;
+ }
+ if (list_empty(&mm->mmlist)) {
+ spin_lock(&mmlist_lock);
+ if (list_empty(&mm->mmlist))
+ list_add(&mm->mmlist, &init_mm.mmlist);
+ spin_unlock(&mmlist_lock);
+ }
dec_mm_counter(mm, MM_ANONPAGES);
- rp->lazyfreed++;
- goto discard;
- }
-
- if (swap_duplicate(entry) < 0) {
- set_pte_at(mm, address, pte, pteval);
- ret = SWAP_FAIL;
- goto out_unmap;
- }
- if (list_empty(&mm->mmlist)) {
- spin_lock(&mmlist_lock);
- if (list_empty(&mm->mmlist))
- list_add(&mm->mmlist, &init_mm.mmlist);
- spin_unlock(&mmlist_lock);
- }
- dec_mm_counter(mm, MM_ANONPAGES);
- inc_mm_counter(mm, MM_SWAPENTS);
- swp_pte = swp_entry_to_pte(entry);
- if (pte_soft_dirty(pteval))
- swp_pte = pte_swp_mksoft_dirty(swp_pte);
- set_pte_at(mm, address, pte, swp_pte);
- } else
- dec_mm_counter(mm, mm_counter_file(page));
-
+ inc_mm_counter(mm, MM_SWAPENTS);
+ swp_pte = swp_entry_to_pte(entry);
+ if (pte_soft_dirty(pteval))
+ swp_pte = pte_swp_mksoft_dirty(swp_pte);
+ set_pte_at(mm, address, pcw.pte, swp_pte);
+ } else
+ dec_mm_counter(mm, mm_counter_file(page));
discard:
- page_remove_rmap(page, PageHuge(page));
- put_page(page);
-
-out_unmap:
- pte_unmap_unlock(pte, ptl);
- if (ret != SWAP_FAIL && ret != SWAP_MLOCK && !(flags & TTU_MUNLOCK))
+ page_remove_rmap(subpage, PageHuge(page));
+ put_page(page);
mmu_notifier_invalidate_page(mm, address);
-out:
+ }
return ret;
}
@@ -1630,7 +1636,7 @@ static bool invalid_migration_vma(struct vm_area_struct *vma, void *arg)
static int page_mapcount_is_zero(struct page *page)
{
- return !page_mapcount(page);
+ return !total_mapcount(page);
}
/**
--
2.11.0
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