The patch titled
Subject: mm/pagewalk: replace mm_walk->skip with more general mm_walk->control
has been removed from the -mm tree. Its filename was
mm-pagewalk-replace-mm_walk-skip-with-more-general-mm_walk-control.patch
This patch was dropped because it was nacked
------------------------------------------------------
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Subject: mm/pagewalk: replace mm_walk->skip with more general mm_walk->control
Originally mm_walk->skip is used to determine whether we walk over a vma
or not. But this is not enough because one of the page table walker's
caller subpage_mark_vma_nohuge(), will need another behavior PTWALK_BREAK,
which let us break current loop and continue from the beginning of the
next loop.
To implement this behavior and make it extensible for future users, this
patch replaces mm_walk->skip with more flexible mm_walk->control, and
changes its default value to PTWALK_NEXT (which is equivalent to present
walk->skip == 1.) This is because PTWALK_NEXT provides the behavior which
is most likely to be used globally.
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 20 ++++------
include/linux/mm.h | 13 +++++--
mm/memcontrol.c | 5 +-
mm/mempolicy.c | 3 -
mm/pagewalk.c | 79 ++++++++++++++++++++++++++-----------------
5 files changed, 71 insertions(+), 49 deletions(-)
diff -puN fs/proc/task_mmu.c~mm-pagewalk-replace-mm_walk-skip-with-more-general-mm_walk-control fs/proc/task_mmu.c
--- a/fs/proc/task_mmu.c~mm-pagewalk-replace-mm_walk-skip-with-more-general-mm_walk-control
+++ a/fs/proc/task_mmu.c
@@ -508,9 +508,8 @@ static int smaps_pmd(pmd_t *pmd, unsigne
smaps_pte((pte_t *)pmd, addr, addr + HPAGE_PMD_SIZE, walk);
spin_unlock(ptl);
mss->anonymous_thp += HPAGE_PMD_SIZE;
- /* don't call smaps_pte() */
- walk->skip = 1;
- }
+ } else
+ walk->control = PTWALK_DOWN;
return 0;
}
@@ -821,13 +820,14 @@ static int clear_refs_test_walk(unsigned
* Writing 4 to /proc/pid/clear_refs affects all pages.
*/
if (cp->type == CLEAR_REFS_ANON && vma->vm_file)
- walk->skip = 1;
+ return 0;
if (cp->type == CLEAR_REFS_MAPPED && !vma->vm_file)
- walk->skip = 1;
+ return 0;
if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
if (vma->vm_flags & VM_SOFTDIRTY)
vma->vm_flags &= ~VM_SOFTDIRTY;
}
+ walk->control = PTWALK_DOWN;
return 0;
}
@@ -1066,9 +1066,8 @@ static int pagemap_pmd(pmd_t *pmd, unsig
break;
}
spin_unlock(ptl);
- /* don't call pagemap_pte() */
- walk->skip = 1;
- }
+ } else
+ walk->control = PTWALK_DOWN;
return err;
}
@@ -1348,9 +1347,8 @@ static int gather_pmd_stats(pmd_t *pmd,
gather_stats(page, md, pte_dirty(huge_pte),
HPAGE_PMD_SIZE/PAGE_SIZE);
spin_unlock(ptl);
- /* don't call gather_pte_stats() */
- walk->skip = 1;
- }
+ } else
+ walk->control = PTWALK_DOWN;
return 0;
}
#ifdef CONFIG_HUGETLB_PAGE
diff -puN include/linux/mm.h~mm-pagewalk-replace-mm_walk-skip-with-more-general-mm_walk-control include/linux/mm.h
--- a/include/linux/mm.h~mm-pagewalk-replace-mm_walk-skip-with-more-general-mm_walk-control
+++ a/include/linux/mm.h
@@ -1112,8 +1112,7 @@ void unmap_vmas(struct mmu_gather *tlb,
* walk_page_test() for how the skip control works.
* @mm: mm_struct representing the target process of page table walk
* @vma: vma currently walked
- * @skip: internal control flag which is set when we skip the lower
- * level entries.
+ * @control: walk control flag
* @private: private data for callbacks' use
*
* (see the comment on walk_page_range() for more details)
@@ -1131,10 +1130,18 @@ struct mm_walk {
struct mm_walk *walk);
struct mm_struct *mm;
struct vm_area_struct *vma;
- int skip;
+ int control;
void *private;
};
+enum mm_walk_control {
+ PTWALK_NEXT = 0, /* Go to the next entry in the same level or
+ * the next vma. This is default behavior. */
+ PTWALK_DOWN, /* Go down to lower level */
+ PTWALK_BREAK, /* Break current loop and continue from the
+ * next loop */
+};
+
int walk_page_range(unsigned long addr, unsigned long end,
struct mm_walk *walk);
int walk_page_vma(struct vm_area_struct *vma, struct mm_walk *walk);
diff -puN mm/memcontrol.c~mm-pagewalk-replace-mm_walk-skip-with-more-general-mm_walk-control mm/memcontrol.c
--- a/mm/memcontrol.c~mm-pagewalk-replace-mm_walk-skip-with-more-general-mm_walk-control
+++ a/mm/memcontrol.c
@@ -6670,9 +6670,8 @@ static int mem_cgroup_count_precharge_pm
if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
mc.precharge += HPAGE_PMD_NR;
spin_unlock(ptl);
- /* don't call mem_cgroup_count_precharge_pte() */
- walk->skip = 1;
- }
+ } else
+ skip->control = PTWALK_DOWN;
return 0;
}
diff -puN mm/mempolicy.c~mm-pagewalk-replace-mm_walk-skip-with-more-general-mm_walk-control mm/mempolicy.c
--- a/mm/mempolicy.c~mm-pagewalk-replace-mm_walk-skip-with-more-general-mm_walk-control
+++ a/mm/mempolicy.c
@@ -596,7 +596,6 @@ static int queue_pages_test_walk(unsigne
}
qp->prev = vma;
- walk->skip = 1;
if (vma->vm_flags & VM_PFNMAP)
return 0;
@@ -610,7 +609,7 @@ static int queue_pages_test_walk(unsigne
((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
vma_migratable(vma)))
/* queue pages from current vma */
- walk->skip = 0;
+ walk->control = PTWALK_DOWN;
return 0;
}
diff -puN mm/pagewalk.c~mm-pagewalk-replace-mm_walk-skip-with-more-general-mm_walk-control mm/pagewalk.c
--- a/mm/pagewalk.c~mm-pagewalk-replace-mm_walk-skip-with-more-general-mm_walk-control
+++ a/mm/pagewalk.c
@@ -3,22 +3,12 @@
#include <linux/sched.h>
#include <linux/hugetlb.h>
-/*
- * Check the current skip status of page table walker.
- *
- * Here what I mean by skip is to skip lower level walking, and that was
- * determined for each entry independently. For example, when walk_pmd_range
- * handles a pmd_trans_huge we don't have to walk over ptes under that pmd,
- * and the skipping does not affect the walking over ptes under other pmds.
- * That's why we reset @walk->skip after tested.
- */
-static bool skip_lower_level_walking(struct mm_walk *walk)
+static int get_reset_walk_control(struct mm_walk *walk)
{
- if (walk->skip) {
- walk->skip = 0;
- return true;
- }
- return false;
+ int ret = walk->control;
+ /* Reset to default value */
+ walk->control = PTWALK_NEXT;
+ return ret;
}
static int walk_pte_range(pmd_t *pmd, unsigned long addr,
@@ -47,7 +37,18 @@ static int walk_pte_range(pmd_t *pmd, un
err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, walk);
if (err)
break;
+ switch (get_reset_walk_control(walk)) {
+ case PTWALK_NEXT:
+ continue;
+ case PTWALK_DOWN:
+ break;
+ case PTWALK_BREAK:
+ goto out_unlock;
+ default:
+ BUG();
+ }
} while (pte++, addr += PAGE_SIZE, addr < end);
+out_unlock:
pte_unmap_unlock(orig_pte, ptl);
cond_resched();
return addr == end ? 0 : err;
@@ -75,10 +76,16 @@ again:
if (walk->pmd_entry) {
err = walk->pmd_entry(pmd, addr, next, walk);
- if (skip_lower_level_walking(walk))
- continue;
if (err)
break;
+ switch (get_reset_walk_control(walk)) {
+ case PTWALK_NEXT:
+ continue;
+ case PTWALK_DOWN:
+ break;
+ default:
+ BUG();
+ }
}
if (walk->pte_entry) {
@@ -204,13 +211,13 @@ static inline int walk_hugetlb_range(uns
#endif /* CONFIG_HUGETLB_PAGE */
/*
- * Decide whether we really walk over the current vma on [@start, @end)
- * or skip it. When we skip it, we set @walk->skip to 1.
- * The return value is used to control the page table walking to
- * continue (for zero) or not (for non-zero).
+ * Decide whether we really walk over the current vma on [@start, @end) or
+ * skip it. If we walk over it, we should set @walk->control to PTWALK_DOWN.
+ * Otherwise, we skip it. The return value is used to control the current
+ * walking to continue (for zero) or terminate (for non-zero).
*
- * Default check (only VM_PFNMAP check for now) is used when the caller
- * doesn't define test_walk() callback.
+ * We fall through to the default check if the caller doesn't define its own
+ * test_walk() callback.
*/
static int walk_page_test(unsigned long start, unsigned long end,
struct mm_walk *walk)
@@ -224,8 +231,8 @@ static int walk_page_test(unsigned long
* Do not walk over vma(VM_PFNMAP), because we have no valid struct
* page backing a VM_PFNMAP range. See also commit a9ff785e4437.
*/
- if (vma->vm_flags & VM_PFNMAP)
- walk->skip = 1;
+ if (!(vma->vm_flags & VM_PFNMAP))
+ walk->control = PTWALK_DOWN;
return 0;
}
@@ -266,7 +273,7 @@ static int __walk_page_range(unsigned lo
* defines test_walk(), pmd_entry(), and pte_entry(), then callbacks are
* called in the order of test_walk(), pmd_entry(), and pte_entry().
* If you don't want to go down to lower level at some point and move to
- * the next entry in the same level, you set @walk->skip to 1.
+ * the next entry in the same level, you set @walk->control to PTWALK_DOWN.
* For example if you succeed to handle some pmd entry as trans_huge entry,
* you need not call walk_pte_range() any more, so set it to avoid that.
* We can't determine whether to go down to lower level with the return
@@ -310,10 +317,16 @@ int walk_page_range(unsigned long start,
next = min(end, vma->vm_end);
err = walk_page_test(start, next, walk);
- if (skip_lower_level_walking(walk))
- continue;
if (err)
break;
+ switch (get_reset_walk_control(walk)) {
+ case PTWALK_NEXT:
+ continue;
+ case PTWALK_DOWN:
+ break;
+ default:
+ BUG();
+ }
}
err = __walk_page_range(start, next, walk);
if (err)
@@ -333,9 +346,15 @@ int walk_page_vma(struct vm_area_struct
VM_BUG_ON(!vma);
walk->vma = vma;
err = walk_page_test(vma->vm_start, vma->vm_end, walk);
- if (skip_lower_level_walking(walk))
- return 0;
if (err)
return err;
+ switch (get_reset_walk_control(walk)) {
+ case PTWALK_NEXT:
+ return 0;
+ case PTWALK_DOWN:
+ break;
+ default:
+ BUG();
+ }
return __walk_page_range(vma->vm_start, vma->vm_end, walk);
}
_
Patches currently in -mm which might be from n-horiguchi@xxxxxxxxxxxxx are
hwpoison-fix-the-handling-path-of-the-victimized-page-frame-that-belong-to-non-lur.patch
mm-hugetlbfs-fix-rmapping-for-anonymous-hugepages-with-page_pgoff.patch
mm-hugetlbfs-fix-rmapping-for-anonymous-hugepages-with-page_pgoff-v2.patch
mm-hugetlbfs-fix-rmapping-for-anonymous-hugepages-with-page_pgoff-v3.patch
mm-hugetlbfs-fix-rmapping-for-anonymous-hugepages-with-page_pgoff-v3-fix.patch
mm-pagewalk-replace-mm_walk-skip-with-more-general-mm_walk-control-fix.patch
madvise-cleanup-swapin_walk_pmd_entry.patch
madvise-cleanup-swapin_walk_pmd_entry-fix.patch
memcg-separate-mem_cgroup_move_charge_pte_range.patch
memcg-separate-mem_cgroup_move_charge_pte_range-checkpatch-fixes.patch
arch-powerpc-mm-subpage-protc-cleanup-subpage_walk_pmd_entry.patch
mm-pagewalk-move-pmd_trans_huge_lock-from-callbacks-to-common-code.patch
mm-pagewalk-move-pmd_trans_huge_lock-from-callbacks-to-common-code-checkpatch-fixes.patch
mincore-apply-page-table-walker-on-do_mincore.patch
mincore-apply-page-table-walker-on-do_mincore-fix.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
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