Hi.
This patch tries to fix the potential rss accounting race where we
fiddle with mm->rss without holding the page_table_lock.
In addition to the places this patch touches there are some places
in fs/ where mm->rss is touched. But I am not sure of the finer
points of this code, so perhaps somebody else could have a look?
The files are binfmt_aout.c, binfmt_elf.c, and exec.c.
It applies against ac12 and 241p11.
Please comment. Or else I will continue to sumbit it :)
diff -aur linux-2.4.1-pre11-clean/mm/memory.c linux/mm/memory.c
--- linux-2.4.1-pre11-clean/mm/memory.c Sun Jan 28 20:53:13 2001
+++ linux/mm/memory.c Sun Jan 28 22:43:04 2001
@@ -377,7 +377,6 @@
address = (address + PGDIR_SIZE) & PGDIR_MASK;
dir++;
} while (address && (address < end));
- spin_unlock(&mm->page_table_lock);
/*
* Update rss for the mm_struct (not necessarily current->mm)
* Notice that rss is an unsigned long.
@@ -386,6 +385,7 @@
mm->rss -= freed;
else
mm->rss = 0;
+ spin_unlock(&mm->page_table_lock);
}
@@ -1038,7 +1038,9 @@
flush_icache_page(vma, page);
}
+ spin_lock(&mm->page_table_lock);
mm->rss++;
+ spin_unlock(&mm->page_table_lock);
pte = mk_pte(page, vma->vm_page_prot);
@@ -1072,7 +1074,9 @@
return -1;
clear_user_highpage(page, addr);
entry = pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
+ spin_lock(&mm->page_table_lock);
mm->rss++;
+ spin_unlock(&mm->page_table_lock);
flush_page_to_ram(page);
}
set_pte(page_table, entry);
@@ -1111,7 +1115,9 @@
return 0;
if (new_page == NOPAGE_OOM)
return -1;
+ spin_lock(&mm->page_table_lock);
++mm->rss;
+ spin_unlock(&mm->page_table_lock);
/*
* This silly early PAGE_DIRTY setting removes a race
* due to the bad i386 page protection. But it's valid
diff -aur linux-2.4.1-pre11-clean/mm/mmap.c linux/mm/mmap.c
--- linux-2.4.1-pre11-clean/mm/mmap.c Sat Dec 30 18:35:19 2000
+++ linux/mm/mmap.c Sun Jan 28 22:43:04 2001
@@ -879,8 +879,8 @@
spin_lock(&mm->page_table_lock);
mpnt = mm->mmap;
mm->mmap = mm->mmap_avl = mm->mmap_cache = NULL;
- spin_unlock(&mm->page_table_lock);
mm->rss = 0;
+ spin_unlock(&mm->page_table_lock);
mm->total_vm = 0;
mm->locked_vm = 0;
while (mpnt) {
diff -aur linux-2.4.1-pre11-clean/mm/swapfile.c linux/mm/swapfile.c
--- linux-2.4.1-pre11-clean/mm/swapfile.c Fri Dec 29 23:07:24 2000
+++ linux/mm/swapfile.c Sun Jan 28 22:43:04 2001
@@ -231,7 +231,9 @@
set_pte(dir, pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
swap_free(entry);
get_page(page);
+ spin_lock(&vma->vm_mm->page_table_lock);
++vma->vm_mm->rss;
+ spin_unlock(&vma->vm_mm->page_table_lock);
}
static inline void unuse_pmd(struct vm_area_struct * vma, pmd_t *dir,
diff -aur linux-2.4.1-pre11-clean/mm/vmscan.c linux/mm/vmscan.c
--- linux-2.4.1-pre11-clean/mm/vmscan.c Sun Jan 28 20:53:13 2001
+++ linux/mm/vmscan.c Mon Jan 29 22:09:18 2001
@@ -72,7 +72,9 @@
swap_duplicate(entry);
set_pte(page_table, swp_entry_to_pte(entry));
drop_pte:
+ spin_lock(&mm->page_table_lock);
mm->rss--;
+ spin_unlock(&mm->page_table_lock);
if (!page->age)
deactivate_page(page);
UnlockPage(page);
--
Regards,
Rasmus([EMAIL PROTECTED])
I've never had major knee surgery on any other part of my body.
-Winston Bennett, University of Kentucky basketball forward
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