The patch titled
htlb forget rss with pt sharing
has been added to the -mm tree. Its filename is
htlb-forget-rss-with-pt-sharing.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: htlb forget rss with pt sharing
From: "Chen, Kenneth W" <kenneth.w.chen@xxxxxxxxx>
Imprecise RSS accounting is an irritating ill effect with pt sharing. After
consulted with several VM experts, I have tried various methods to solve that
problem: (1) iterate through all mm_structs that share the PT and increment
count; (2) keep RSS count in page table structure and then sum them up at
reporting time. None of the above methods yield any satisfactory
implementation.
Since process RSS accounting is pure information only, I propose we don't
count them at all for hugetlb page. rlimit has such field, though there is
absolutely no enforcement on limiting that resource. One other method is to
account all RSS at hugetlb mmap time regardless they are faulted or not. I
opt for the simplicity of no accounting at all.
Signed-off-by: Ken Chen <kenneth.w.chen@xxxxxxxxx>
Cc: Hugh Blemings <hab@xxxxxxxxxxx>
Cc: Dave McCracken <dmccr@xxxxxxxxxx>
Cc: William Lee Irwin III <wli@xxxxxxxxxxxxxx>
Cc: "Luck, Tony" <tony.luck@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
Cc: Adam Litke <agl@xxxxxxxxxx>
Cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
mm/hugetlb.c | 8 --------
1 files changed, 8 deletions(-)
diff -puN mm/hugetlb.c~htlb-forget-rss-with-pt-sharing mm/hugetlb.c
--- a/mm/hugetlb.c~htlb-forget-rss-with-pt-sharing
+++ a/mm/hugetlb.c
@@ -344,7 +344,6 @@ int copy_hugetlb_page_range(struct mm_st
entry = *src_pte;
ptepage = pte_page(entry);
get_page(ptepage);
- add_mm_counter(dst, file_rss, HPAGE_SIZE / PAGE_SIZE);
set_huge_pte_at(dst, addr, dst_pte, entry);
}
spin_unlock(&src->page_table_lock);
@@ -377,10 +376,6 @@ void __unmap_hugepage_range(struct vm_ar
BUG_ON(end & ~HPAGE_MASK);
spin_lock(&mm->page_table_lock);
-
- /* Update high watermark before we lower rss */
- update_hiwater_rss(mm);
-
for (address = start; address < end; address += HPAGE_SIZE) {
ptep = huge_pte_offset(mm, address);
if (!ptep)
@@ -395,9 +390,7 @@ void __unmap_hugepage_range(struct vm_ar
page = pte_page(pte);
list_add(&page->lru, &page_list);
- add_mm_counter(mm, file_rss, (int) -(HPAGE_SIZE / PAGE_SIZE));
}
-
spin_unlock(&mm->page_table_lock);
flush_tlb_range(vma, start, end);
list_for_each_entry_safe(page, tmp, &page_list, lru) {
@@ -520,7 +513,6 @@ retry:
if (!pte_none(*ptep))
goto backout;
- add_mm_counter(mm, file_rss, HPAGE_SIZE / PAGE_SIZE);
new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
&& (vma->vm_flags & VM_SHARED)));
set_huge_pte_at(mm, address, ptep, new_pte);
_
Patches currently in -mm which might be from kenneth.w.chen@xxxxxxxxx are
__unmap_hugepage_range-add-comment.patch
shared-page-table-for-hugetlb-page-v4.patch
htlb-forget-rss-with-pt-sharing.patch
-
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