The patch titled
mm: more rmpa debugging
has been added to the -mm tree. Its filename is
mm-more-rmap-debugging.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: mm: more rmpa debugging
From: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Add more debugging in the rmap code in an attempt to locate to source of
the occasional "mapcount went negative" assertions.
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/linux/rmap.h | 2 +-
mm/filemap_xip.c | 2 +-
mm/fremap.c | 2 +-
mm/memory.c | 4 ++--
mm/rmap.c | 13 ++++++++++---
5 files changed, 15 insertions(+), 8 deletions(-)
diff -puN include/linux/rmap.h~mm-more-rmap-debugging include/linux/rmap.h
--- a/include/linux/rmap.h~mm-more-rmap-debugging
+++ a/include/linux/rmap.h
@@ -72,7 +72,7 @@ void __anon_vma_link(struct vm_area_stru
void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
void page_add_file_rmap(struct page *);
-void page_remove_rmap(struct page *);
+void page_remove_rmap(struct page *, struct vm_area_struct *);
/**
* page_dup_rmap - duplicate pte mapping to a page
diff -puN mm/filemap_xip.c~mm-more-rmap-debugging mm/filemap_xip.c
--- a/mm/filemap_xip.c~mm-more-rmap-debugging
+++ a/mm/filemap_xip.c
@@ -189,7 +189,7 @@ __xip_unmap (struct address_space * mapp
/* Nuke the page table entry. */
flush_cache_page(vma, address, pte_pfn(*pte));
pteval = ptep_clear_flush(vma, address, pte);
- page_remove_rmap(page);
+ page_remove_rmap(page, vma);
dec_mm_counter(mm, file_rss);
BUG_ON(pte_dirty(pteval));
pte_unmap_unlock(pte, ptl);
diff -puN mm/fremap.c~mm-more-rmap-debugging mm/fremap.c
--- a/mm/fremap.c~mm-more-rmap-debugging
+++ a/mm/fremap.c
@@ -33,7 +33,7 @@ static int zap_pte(struct mm_struct *mm,
if (page) {
if (pte_dirty(pte))
set_page_dirty(page);
- page_remove_rmap(page);
+ page_remove_rmap(page, vma);
page_cache_release(page);
}
} else {
diff -puN mm/memory.c~mm-more-rmap-debugging mm/memory.c
--- a/mm/memory.c~mm-more-rmap-debugging
+++ a/mm/memory.c
@@ -681,7 +681,7 @@ static unsigned long zap_pte_range(struc
mark_page_accessed(page);
file_rss--;
}
- page_remove_rmap(page);
+ page_remove_rmap(page, vma);
tlb_remove_page(tlb, page);
continue;
}
@@ -1586,7 +1586,7 @@ gotten:
page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
if (likely(pte_same(*page_table, orig_pte))) {
if (old_page) {
- page_remove_rmap(old_page);
+ page_remove_rmap(old_page, vma);
if (!PageAnon(old_page)) {
dec_mm_counter(mm, file_rss);
inc_mm_counter(mm, anon_rss);
diff -puN mm/rmap.c~mm-more-rmap-debugging mm/rmap.c
--- a/mm/rmap.c~mm-more-rmap-debugging
+++ a/mm/rmap.c
@@ -47,6 +47,7 @@
#include <linux/rmap.h>
#include <linux/rcupdate.h>
#include <linux/module.h>
+#include <linux/kallsyms.h>
#include <asm/tlbflush.h>
@@ -567,14 +568,20 @@ void page_add_file_rmap(struct page *pag
*
* The caller needs to hold the pte lock.
*/
-void page_remove_rmap(struct page *page)
+void page_remove_rmap(struct page *page, struct vm_area_struct *vma)
{
if (atomic_add_negative(-1, &page->_mapcount)) {
if (unlikely(page_mapcount(page) < 0)) {
printk (KERN_EMERG "Eeek! page_mapcount(page) went negative! (%d)\n", page_mapcount(page));
+ printk (KERN_EMERG " page pfn = %lx\n", page_to_pfn(page));
printk (KERN_EMERG " page->flags = %lx\n", page->flags);
printk (KERN_EMERG " page->count = %x\n", page_count(page));
printk (KERN_EMERG " page->mapping = %p\n", page->mapping);
+ print_symbol (KERN_EMERG " vma->vm_ops = %s\n", (unsigned long)vma->vm_ops);
+ if (vma->vm_ops)
+ print_symbol (KERN_EMERG " vma->vm_ops->nopage = %s\n", (unsigned long)vma->vm_ops->nopage);
+ if (vma->vm_file && vma->vm_file->f_op)
+ print_symbol (KERN_EMERG " vma->vm_file->f_op->mmap = %s\n", (unsigned long)vma->vm_file->f_op->mmap);
BUG();
}
@@ -679,7 +686,7 @@ static int try_to_unmap_one(struct page
dec_mm_counter(mm, file_rss);
- page_remove_rmap(page);
+ page_remove_rmap(page, vma);
page_cache_release(page);
out_unmap:
@@ -769,7 +776,7 @@ static void try_to_unmap_cluster(unsigne
if (pte_dirty(pteval))
set_page_dirty(page);
- page_remove_rmap(page);
+ page_remove_rmap(page, vma);
page_cache_release(page);
dec_mm_counter(mm, file_rss);
(*mapcount)--;
_
Patches currently in -mm which might be from nickpiggin@xxxxxxxxxxxx are
mm-more-rmap-debugging.patch
cpuset-remove-sched-domain-hooks-from-cpusets.patch
mm-only-sched-add-a-few-scheduler-event-counters.patch
sched2-sched-domain-sysctl.patch
sched2-sched-domain-sysctl-use-ctl_unnumbered.patch
-
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