The patch titled
smaps: teach smaps_pte_range() about THP pmds
has been added to the -mm tree. Its filename is
smaps-teach-smaps_pte_range-about-thp-pmds.patch
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out what to do about this
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------------------------------------------------------
Subject: smaps: teach smaps_pte_range() about THP pmds
From: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
This adds code to explicitly detect and handle pmd_trans_huge() pmds. It
then passes HPAGE_SIZE units in to the smap_pte_entry() function instead
of PAGE_SIZE.
This means that using /proc/$pid/smaps now will no longer cause THPs to be
broken down in to small pages.
Signed-off-by: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Eric B Munson <emunson@xxxxxxxxx>
Tested-by: Eric B Munson <emunson@xxxxxxxxx>
Acked-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Michael J Wolf <mjwolf@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Matt Mackall <mpm@xxxxxxxxxxx>
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
diff -puN fs/proc/task_mmu.c~smaps-teach-smaps_pte_range-about-thp-pmds fs/proc/task_mmu.c
--- a/fs/proc/task_mmu.c~smaps-teach-smaps_pte_range-about-thp-pmds
+++ a/fs/proc/task_mmu.c
@@ -1,5 +1,6 @@
#include <linux/mm.h>
#include <linux/hugetlb.h>
+#include <linux/huge_mm.h>
#include <linux/mount.h>
#include <linux/seq_file.h>
#include <linux/highmem.h>
@@ -7,6 +8,7 @@
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/mempolicy.h>
+#include <linux/rmap.h>
#include <linux/swap.h>
#include <linux/swapops.h>
@@ -385,8 +387,25 @@ static int smaps_pte_range(pmd_t *pmd, u
pte_t *pte;
spinlock_t *ptl;
- split_huge_page_pmd(walk->mm, pmd);
-
+ spin_lock(&walk->mm->page_table_lock);
+ if (pmd_trans_huge(*pmd)) {
+ if (pmd_trans_splitting(*pmd)) {
+ spin_unlock(&walk->mm->page_table_lock);
+ wait_split_huge_page(vma->anon_vma, pmd);
+ } else {
+ smaps_pte_entry(*(pte_t *)pmd, addr,
+ HPAGE_PMD_SIZE, walk);
+ spin_unlock(&walk->mm->page_table_lock);
+ return 0;
+ }
+ } else {
+ spin_unlock(&walk->mm->page_table_lock);
+ }
+ /*
+ * The mmap_sem held all the way back in m_start() is what
+ * keeps khugepaged out of here and from collapsing things
+ * in here.
+ */
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
for (; addr != end; pte++, addr += PAGE_SIZE)
smaps_pte_entry(*pte, addr, PAGE_SIZE, walk);
_
Patches currently in -mm which might be from dave@xxxxxxxxxxxxxxxxxx are
pagewalk-only-split-huge-pages-when-necessary.patch
smaps-break-out-smaps_pte_entry-from-smaps_pte_range.patch
smaps-pass-pte-size-argument-in-to-smaps_pte_entry.patch
smaps-teach-smaps_pte_range-about-thp-pmds.patch
smaps-have-smaps-show-transparent-huge-pages.patch
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