Fix unuse_pmd() OOM handling for pte_chain_alloc() failures.
Unfortunately I'm not able to trigger anything more than light
swapping loads to test this with.
diff -urpN merge-2.5.66-8/mm/swapfile.c merge-2.5.66-9/mm/swapfile.c
--- merge-2.5.66-8/mm/swapfile.c 2003-03-24 14:00:09.000000000 -0800
+++ merge-2.5.66-9/mm/swapfile.c 2003-03-25 08:30:03.000000000 -0800
@@ -400,11 +400,10 @@ unuse_pte(struct vm_area_struct *vma, un
/* mmlist_lock and vma->vm_mm->page_table_lock are held */
static void unuse_pmd(struct vm_area_struct * vma, pmd_t *dir,
unsigned long address, unsigned long size, unsigned long offset,
- swp_entry_t entry, struct page* page)
+ swp_entry_t entry, struct page* page, struct pte_chain **pte_chainp)
{
pte_t * pte;
unsigned long end;
- struct pte_chain *pte_chain = NULL;
if (pmd_none(*dir))
return;
@@ -420,24 +419,24 @@ static void unuse_pmd(struct vm_area_str
if (end > PMD_SIZE)
end = PMD_SIZE;
do {
- /*
- * FIXME: handle pte_chain_alloc() failures
- */
- if (pte_chain == NULL)
- pte_chain = pte_chain_alloc(GFP_ATOMIC);
unuse_pte(vma, offset+address-vma->vm_start,
- pte, entry, page, &pte_chain);
+ pte, entry, page, pte_chainp);
address += PAGE_SIZE;
pte++;
+ if (!*pte_chainp)
+ *pte_chainp = pte_chain_alloc(GFP_ATOMIC);
+ if (!*pte_chainp) {
+ pte_unmap(pte-1);
+ return;
+ }
} while (address && (address < end));
pte_unmap(pte - 1);
- pte_chain_free(pte_chain);
}
/* mmlist_lock and vma->vm_mm->page_table_lock are held */
static void unuse_pgd(struct vm_area_struct * vma, pgd_t *dir,
unsigned long address, unsigned long size,
- swp_entry_t entry, struct page* page)
+ swp_entry_t entry, struct page* page, struct pte_chain **pte_chainp)
{
pmd_t * pmd;
unsigned long offset, end;
@@ -459,7 +458,9 @@ static void unuse_pgd(struct vm_area_str
BUG();
do {
unuse_pmd(vma, pmd, address, end - address, offset, entry,
- page);
+ page, pte_chainp);
+ if (!*pte_chainp)
+ return;
address = (address + PMD_SIZE) & PMD_MASK;
pmd++;
} while (address && (address < end));
@@ -467,21 +468,24 @@ static void unuse_pgd(struct vm_area_str
/* mmlist_lock and vma->vm_mm->page_table_lock are held */
static void unuse_vma(struct vm_area_struct * vma, pgd_t *pgdir,
- swp_entry_t entry, struct page* page)
+ swp_entry_t entry, struct page* page,
+ struct pte_chain **pte_chainp)
{
unsigned long start = vma->vm_start, end = vma->vm_end;
if (start >= end)
BUG();
do {
- unuse_pgd(vma, pgdir, start, end - start, entry, page);
+ unuse_pgd(vma, pgdir, start, end - start, entry, page, pte_chainp);
+ if (!*pte_chainp)
+ return;
start = (start + PGDIR_SIZE) & PGDIR_MASK;
pgdir++;
} while (start && (start < end));
}
-static void unuse_process(struct mm_struct * mm,
- swp_entry_t entry, struct page* page)
+static void unuse_process(struct mm_struct *mm, swp_entry_t entry,
+ struct page *page, struct pte_chain **pte_chainp)
{
struct vm_area_struct* vma;
@@ -491,7 +495,9 @@ static void unuse_process(struct mm_stru
spin_lock(&mm->page_table_lock);
for (vma = mm->mmap; vma; vma = vma->vm_next) {
pgd_t * pgd = pgd_offset(mm, vma->vm_start);
- unuse_vma(vma, pgd, entry, page);
+ unuse_vma(vma, pgd, entry, page, pte_chainp);
+ if (!*pte_chainp)
+ break;
}
spin_unlock(&mm->page_table_lock);
return;
@@ -551,6 +557,11 @@ static int try_to_unuse(unsigned int typ
int retval = 0;
int reset_overflow = 0;
int shmem;
+ struct pte_chain *pte_chain = pte_chain_alloc(GFP_KERNEL);
+
+ /* if we can't get one to start with we appear to be screwed */
+ if (!pte_chain)
+ return -ENOMEM;
/*
* When searching mms for an entry, a good strategy is to
@@ -638,7 +649,14 @@ static int try_to_unuse(unsigned int typ
if (start_mm == &init_mm)
shmem = shmem_unuse(entry, page);
else
- unuse_process(start_mm, entry, page);
+ unuse_process(start_mm, entry, page, &pte_chain);
+ if (!pte_chain)
+ pte_chain = pte_chain_alloc(GFP_KERNEL);
+ if (!pte_chain) {
+ retval = -ENOMEM;
+ unlock_page(page);
+ break;
+ }
}
if (*swap_map > 1) {
int set_start_mm = (*swap_map >= swcount);
@@ -656,8 +674,22 @@ static int try_to_unuse(unsigned int typ
spin_unlock(&mmlist_lock);
shmem = shmem_unuse(entry, page);
spin_lock(&mmlist_lock);
- } else
- unuse_process(mm, entry, page);
+ } else {
+ unuse_process(mm, entry, page, &pte_chain);
+ if (!pte_chain)
+ pte_chain = pte_chain_alloc(GFP_ATOMIC);
+ if (!pte_chain) {
+ /* we hold a reference to mm */
+ spin_unlock(&mmlist_lock);
+ pte_chain = pte_chain_alloc(GFP_KERNEL);
+ if (!pte_chain) {
+ retval = -ENOMEM;
+ unlock_page(page);
+ goto swap_map_check;
+ }
+ spin_lock(&mmlist_lock);
+ }
+ }
if (set_start_mm && *swap_map < swcount) {
new_start_mm = mm;
set_start_mm = 0;
@@ -741,6 +773,8 @@ static int try_to_unuse(unsigned int typ
cond_resched();
}
+swap_map_check:
+ pte_chain_free(pte_chain);
mmput(start_mm);
if (reset_overflow) {
printk(KERN_WARNING "swapoff: cleared swap entry overflow\n");
-
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This archive was generated by hypermail 2b29 : Mon Mar 31 2003 - 22:00:20 EST