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[PATCH] mm: more rmap debugging

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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@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Nick Piggin 2006-12-22 01:09:33 -08:00 committed by Linus Torvalds
parent 19900cdee2
commit 7de6b80579
5 changed files with 15 additions and 8 deletions
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2
include/linux/rmap.h
View file

@ -72,7 +72,7 @@ void __anon_vma_link(struct vm_area_struct *);
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

2
mm/filemap_xip.c
View file

@ -189,7 +189,7 @@ __xip_unmap (struct address_space * mapping,
/* 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);

2
mm/fremap.c
View file

@ -33,7 +33,7 @@ static int zap_pte(struct mm_struct *mm, struct vm_area_struct *vma,
if (page) {
if (pte_dirty(pte))
set_page_dirty(page);
page_remove_rmap(page);
page_remove_rmap(page, vma);
page_cache_release(page);
}
} else {

4
mm/memory.c
View file

@ -681,7 +681,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
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);

13
mm/rmap.c
View file

@ -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 *page)
*
* 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 *page, struct vm_area_struct *vma,
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(unsigned long cursor,
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)--;