[PATCH 2/5] Swap Migration V4: PF_SWAPWRITE to allow writing to swap
Christoph Lameter
- Use PF_SWAPWRITE in may_write_to_queue() instead of checking for kswapd
and pdflush
- Set PF_SWAPWRITE flag for kswapd and pdflush
Signed-off-by: Christoph Lameter <clam...@sgi.com>
Index: linux-2.6.14-rc5-mm1/include/linux/sched.h
===================================================================
--- linux-2.6.14-rc5-mm1.orig/include/linux/sched.h 2005-10-24 10:27:29.000000000 -0700
+++ linux-2.6.14-rc5-mm1/include/linux/sched.h 2005-10-25 11:07:11.000000000 -0700
@@ -914,6 +914,7 @@ do { if (atomic_dec_and_test(&(tsk)->usa
#define PF_SYNCWRITE 0x00200000 /* I am doing a sync write */
#define PF_BORROWED_MM 0x00400000 /* I am a kthread doing use_mm */
#define PF_RANDOMIZE 0x00800000 /* randomize virtual address space */
+#define PF_SWAPWRITE 0x01000000 /* the process is allowed to write to swap */
/*
* Only the _current_ task can read/write to tsk->flags, but other
Index: linux-2.6.14-rc5-mm1/mm/vmscan.c
===================================================================
--- linux-2.6.14-rc5-mm1.orig/mm/vmscan.c 2005-10-25 08:09:52.000000000 -0700
+++ linux-2.6.14-rc5-mm1/mm/vmscan.c 2005-10-25 11:07:11.000000000 -0700
@@ -263,9 +263,7 @@ static inline int is_page_cache_freeable
static int may_write_to_queue(struct backing_dev_info *bdi)
{
- if (current_is_kswapd())
- return 1;
- if (current_is_pdflush()) /* This is unlikely, but why not... */
+ if (current->flags & PF_SWAPWRITE)
return 1;
if (!bdi_write_congested(bdi))
return 1;
@@ -1279,7 +1277,7 @@ static int kswapd(void *p)
* us from recursively trying to free more memory as we're
* trying to free the first piece of memory in the first place).
*/
- tsk->flags |= PF_MEMALLOC|PF_KSWAPD;
+ tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD;
order = 0;
for ( ; ; ) {
Index: linux-2.6.14-rc5-mm1/mm/pdflush.c
===================================================================
--- linux-2.6.14-rc5-mm1.orig/mm/pdflush.c 2005-10-24 10:27:21.000000000 -0700
+++ linux-2.6.14-rc5-mm1/mm/pdflush.c 2005-10-25 11:07:11.000000000 -0700
@@ -90,7 +90,7 @@ struct pdflush_work {
static int __pdflush(struct pdflush_work *my_work)
{
- current->flags |= PF_FLUSHER;
+ current->flags |= PF_FLUSHER | PF_SWAPWRITE;
my_work->fn = NULL;
my_work->who = current;
INIT_LIST_HEAD(&my_work->list);
-
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Christoph Lameter
Implement functions to isolate pages from the LRU and put them back later.
An earlier implementation was provided by
Hirokazu Takahashi <ta...@valinux.co.jp> and
IWAMOTO Toshihiro <iwa...@valinux.co.jp> for the memory
hotplug project.
From Magnus:
This patch for 2.6.14-rc4-mm1 breaks out isolate_lru_page() and
putpack_lru_page() and makes them inline. I'd like to build my code on
top of this patch, and I think your page eviction code could be built
on top of this patch too - without introducing too much duplicated
code.
Changes V3-V4:
- Remove obsolete second parameter from isolate_lru_page
- Mention the original authors
Signed-off-by: Magnus Damm <magnu...@gmail.com>
Signed-off-by: Christoph Lameter <clam...@sgi.com>
Index: linux-2.6.14-rc5-mm1/include/linux/mm_inline.h
===================================================================
--- linux-2.6.14-rc5-mm1.orig/include/linux/mm_inline.h 2005-10-19 23:23:05.000000000 -0700
+++ linux-2.6.14-rc5-mm1/include/linux/mm_inline.h 2005-10-25 08:09:52.000000000 -0700
@@ -38,3 +38,55 @@ del_page_from_lru(struct zone *zone, str
zone->nr_inactive--;
}
}
+
+/*
+ * Isolate one page from the LRU lists.
+ *
+ * - zone->lru_lock must be held
+ *
+ * Result:
+ * 0 = page not on LRU list
+ * 1 = page removed from LRU list
+ * -1 = page is being freed elsewhere.
+ */
+static inline int
+__isolate_lru_page(struct zone *zone, struct page *page)
+{
+ if (TestClearPageLRU(page)) {
+ if (get_page_testone(page)) {
+ /*
+ * It is being freed elsewhere
+ */
+ __put_page(page);
+ SetPageLRU(page);
+ return -1;
+ } else {
+ if (PageActive(page))
+ del_page_from_active_list(zone, page);
+ else
+ del_page_from_inactive_list(zone, page);
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Add isolated page back on the LRU lists
+ *
+ * - zone->lru_lock must be held
+ * - page must already be removed from other list
+ * - additional call to put_page() is needed
+ */
+static inline void
+__putback_lru_page(struct zone *zone, struct page *page)
+{
+ if (TestSetPageLRU(page))
+ BUG();
+
+ if (PageActive(page))
+ add_page_to_active_list(zone, page);
+ else
+ add_page_to_inactive_list(zone, page);
+}
Index: linux-2.6.14-rc5-mm1/mm/vmscan.c
===================================================================
--- linux-2.6.14-rc5-mm1.orig/mm/vmscan.c 2005-10-24 10:27:30.000000000 -0700
+++ linux-2.6.14-rc5-mm1/mm/vmscan.c 2005-10-25 08:09:52.000000000 -0700
@@ -578,43 +578,75 @@ keep:
*
* Appropriate locks must be held before calling this function.
*
+ * @zone: The zone where lru_lock is held.
* @nr_to_scan: The number of pages to look through on the list.
* @src: The LRU list to pull pages off.
* @dst: The temp list to put pages on to.
- * @scanned: The number of pages that were scanned.
*
- * returns how many pages were moved onto *@dst.
+ * returns the number of pages that were scanned.
*/
-static int isolate_lru_pages(int nr_to_scan, struct list_head *src,
- struct list_head *dst, int *scanned)
+static int isolate_lru_pages(struct zone *zone, int nr_to_scan,
+ struct list_head *src, struct list_head *dst)
{
- int nr_taken = 0;
struct page *page;
- int scan = 0;
+ int scanned = 0;
+ int rc;
- while (scan++ < nr_to_scan && !list_empty(src)) {
+ while (scanned++ < nr_to_scan && !list_empty(src)) {
page = lru_to_page(src);
prefetchw_prev_lru_page(page, src, flags);
- if (!TestClearPageLRU(page))
- BUG();
- list_del(&page->lru);
- if (get_page_testone(page)) {
- /*
- * It is being freed elsewhere
- */
- __put_page(page);
- SetPageLRU(page);
- list_add(&page->lru, src);
- continue;
- } else {
+ rc = __isolate_lru_page(zone, page);
+
+ BUG_ON(rc == 0); /* PageLRU(page) must be true */
+
+ if (rc == 1) /* Succeeded to isolate page */
list_add(&page->lru, dst);
- nr_taken++;
+
+ if (rc == -1) { /* Not possible to isolate */
+ list_del(&page->lru);
+ list_add(&page->lru, src);
}
}
- *scanned = scan;
- return nr_taken;
+ return scanned;
+}
+
+static void lru_add_drain_per_cpu(void *dummy)
+{
+ lru_add_drain();
+}
+
+/*
+ * Isolate one page from the LRU lists and put it on the
+ * indicated list. Do necessary cache draining if the
+ * page is not on the LRU lists yet.
+ *
+ * Result:
+ * 0 = page not on LRU list
+ * 1 = page removed from LRU list and added to the specified list.
+ * -1 = page is being freed elsewhere.
+ */
+int isolate_lru_page(struct page *page)
+{
+ int rc = 0;
+ struct zone *zone = page_zone(page);
+
+redo:
+ spin_lock_irq(&zone->lru_lock);
+ rc = __isolate_lru_page(zone, page);
+ spin_unlock_irq(&zone->lru_lock);
+ if (rc == 0) {
+ /*
+ * Maybe this page is still waiting for a cpu to drain it
+ * from one of the lru lists?
+ */
+ smp_call_function(&lru_add_drain_per_cpu, NULL, 0 , 1);
+ lru_add_drain();
+ if (PageLRU(page))
+ goto redo;
+ }
+ return rc;
}
/*
@@ -632,18 +664,15 @@ static void shrink_cache(struct zone *zo
spin_lock_irq(&zone->lru_lock);
while (max_scan > 0) {
struct page *page;
- int nr_taken;
int nr_scan;
int nr_freed;
- nr_taken = isolate_lru_pages(sc->swap_cluster_max,
- &zone->inactive_list,
- &page_list, &nr_scan);
- zone->nr_inactive -= nr_taken;
+ nr_scan = isolate_lru_pages(zone, sc->swap_cluster_max,
+ &zone->inactive_list, &page_list);
zone->pages_scanned += nr_scan;
spin_unlock_irq(&zone->lru_lock);
- if (nr_taken == 0)
+ if (list_empty(&page_list))
goto done;
max_scan -= nr_scan;
@@ -663,13 +692,9 @@ static void shrink_cache(struct zone *zo
*/
while (!list_empty(&page_list)) {
page = lru_to_page(&page_list);
- if (TestSetPageLRU(page))
- BUG();
list_del(&page->lru);
- if (PageActive(page))
- add_page_to_active_list(zone, page);
- else
- add_page_to_inactive_list(zone, page);
+ __putback_lru_page(zone, page);
+
if (!pagevec_add(&pvec, page)) {
spin_unlock_irq(&zone->lru_lock);
__pagevec_release(&pvec);
@@ -683,6 +708,33 @@ done:
}
/*
+ * Add isolated pages on the list back to the LRU
+ * Determines the zone for each pages and takes
+ * the necessary lru lock for each page.
+ *
+ * returns the number of pages put back.
+ */
+int putback_lru_pages(struct list_head *l)
+{
+ struct page * page;
+ struct page * page2;
+ int count = 0;
+
+ list_for_each_entry_safe(page, page2, l, lru) {
+ struct zone *zone = page_zone(page);
+
+ list_del(&page->lru);
+ spin_lock_irq(&zone->lru_lock);
+ __putback_lru_page(zone, page);
+ spin_unlock_irq(&zone->lru_lock);
+ count++;
+ /* Undo the get from isolate_lru_page */
+ put_page(page);
+ }
+ return count;
+}
+
+/*
* This moves pages from the active list to the inactive list.
*
* We move them the other way if the page is referenced by one or more
@@ -718,10 +770,9 @@ refill_inactive_zone(struct zone *zone,
lru_add_drain();
spin_lock_irq(&zone->lru_lock);
- pgmoved = isolate_lru_pages(nr_pages, &zone->active_list,
- &l_hold, &pgscanned);
+ pgscanned = isolate_lru_pages(zone, nr_pages,
+ &zone->active_list, &l_hold);
zone->pages_scanned += pgscanned;
- zone->nr_active -= pgmoved;
spin_unlock_irq(&zone->lru_lock);
/*
Index: linux-2.6.14-rc5-mm1/include/linux/swap.h
===================================================================
--- linux-2.6.14-rc5-mm1.orig/include/linux/swap.h 2005-10-24 10:27:13.000000000 -0700
+++ linux-2.6.14-rc5-mm1/include/linux/swap.h 2005-10-25 08:09:52.000000000 -0700
@@ -176,6 +176,9 @@ extern int zone_reclaim(struct zone *, u
extern int shrink_all_memory(int);
extern int vm_swappiness;
+extern int isolate_lru_page(struct page *p);
+extern int putback_lru_pages(struct list_head *l);
+
#ifdef CONFIG_MMU
/* linux/mm/shmem.c */
extern int shmem_unuse(swp_entry_t entry, struct page *page);
Christoph Lameter
This patch adds page migration support to the NUMA policy layer. An additional
flag MPOL_MF_MOVE is introduced for mbind. If MPOL_MF_MOVE is specified then
pages that do not conform to the memory policy will be evicted from memory.
When they get pages back in new pages will be allocated following the numa policy.
Changes V3->V4
- migrate_page_add: Do pagelist processing directly instead
of doing it via isolate_lru_page().
- Use the migrate_pages() to evict the pages.
Changes V2->V3
- Add check to not migrate pages shared with other processes (but allow
migration of memory shared between threads having a common mm_struct)
- MPOL_MF_MOVE_ALL to override and move even pages shared with other
processes. This only works if the process issuing this call has
CAP_SYS_RESOURCE because this enables the moving of pages owned
by other processes.
- MPOL_MF_DISCONTIG_OK (internal use only) to not check for continuous VMAs.
Enable MPOL_MF_DISCONTIG_OK if policy to be set is NULL (default policy).
Changes V1->V2
- Add vma_migratable() function for future enhancements.
- No side effects on WARN_ON
- Remove move_pages for now
- Make patch fit 2.6.14-rc4-mm1
Signed-off-by: Christoph Lameter <clam...@sgi.com>
Index: linux-2.6.14-rc5-mm1/mm/mempolicy.c
===================================================================
--- linux-2.6.14-rc5-mm1.orig/mm/mempolicy.c 2005-10-24 10:27:13.000000000 -0700
+++ linux-2.6.14-rc5-mm1/mm/mempolicy.c 2005-10-25 09:09:54.000000000 -0700
@@ -83,9 +83,13 @@
#include <linux/init.h>
#include <linux/compat.h>
#include <linux/mempolicy.h>
+#include <linux/swap.h>
#include <asm/tlbflush.h>
#include <asm/uaccess.h>
+/* Internal MPOL_MF_xxx flags */
+#define MPOL_MF_DISCONTIG_OK (1<<20) /* Skip checks for continuous vmas */
+
static kmem_cache_t *policy_cache;
static kmem_cache_t *sn_cache;
@@ -179,9 +183,62 @@ static struct mempolicy *mpol_new(int mo
return policy;
}
+/* Check if we are the only process mapping the page in question */
+static inline int single_mm_mapping(struct mm_struct *mm,
+ struct address_space *mapping)
+{
+ struct vm_area_struct *vma;
+ struct prio_tree_iter iter;
+ int rc = 1;
+
+ spin_lock(&mapping->i_mmap_lock);
+ vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
+ if (mm != vma->vm_mm) {
+ rc = 0;
+ goto out;
+ }
+ list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
+ if (mm != vma->vm_mm) {
+ rc = 0;
+ goto out;
+ }
+out:
+ spin_unlock(&mapping->i_mmap_lock);
+ return rc;
+}
+
+/*
+ * Add a page to be migrated to the pagelist
+ */
+static void migrate_page_add(struct vm_area_struct *vma,
+ struct page *page, struct list_head *pagelist, unsigned long flags)
+{
+ /*
+ * Avoid migrating a page that is shared by others and not writable.
+ */
+ if ((flags & MPOL_MF_MOVE_ALL) ||
+ PageAnon(page) ||
+ mapping_writably_mapped(page->mapping) ||
+ single_mm_mapping(vma->vm_mm, page->mapping)
+ ) {
+ int rc = isolate_lru_page(page);
+
+ if (rc == 1)
+ list_add(&page->lru, pagelist);
+ /*
+ * If the isolate attempt was not successful
+ * then we just encountered an unswappable
+ * page. Something must be wrong.
+ */
+ WARN_ON(rc == 0);
+ }
+}
+
/* Ensure all existing pages follow the policy. */
static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
- unsigned long addr, unsigned long end, nodemask_t *nodes)
+ unsigned long addr, unsigned long end,
+ nodemask_t *nodes, unsigned long flags,
+ struct list_head *pagelist)
{
pte_t *orig_pte;
pte_t *pte;
@@ -200,15 +257,23 @@ static int check_pte_range(struct vm_are
continue;
}
nid = pfn_to_nid(pfn);
- if (!node_isset(nid, *nodes))
- break;
+ if (!node_isset(nid, *nodes)) {
+ if (pagelist) {
+ struct page *page = pfn_to_page(pfn);
+
+ migrate_page_add(vma, page, pagelist, flags);
+ } else
+ break;
+ }
} while (pte++, addr += PAGE_SIZE, addr != end);
pte_unmap_unlock(orig_pte, ptl);
return addr != end;
}
static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud,
- unsigned long addr, unsigned long end, nodemask_t *nodes)
+ unsigned long addr, unsigned long end,
+ nodemask_t *nodes, unsigned long flags,
+ struct list_head *pagelist)
{
pmd_t *pmd;
unsigned long next;
@@ -218,14 +283,17 @@ static inline int check_pmd_range(struct
next = pmd_addr_end(addr, end);
if (pmd_none_or_clear_bad(pmd))
continue;
- if (check_pte_range(vma, pmd, addr, next, nodes))
+ if (check_pte_range(vma, pmd, addr, next, nodes,
+ flags, pagelist))
return -EIO;
} while (pmd++, addr = next, addr != end);
return 0;
}
static inline int check_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
- unsigned long addr, unsigned long end, nodemask_t *nodes)
+ unsigned long addr, unsigned long end,
+ nodemask_t *nodes, unsigned long flags,
+ struct list_head *pagelist)
{
pud_t *pud;
unsigned long next;
@@ -235,14 +303,17 @@ static inline int check_pud_range(struct
next = pud_addr_end(addr, end);
if (pud_none_or_clear_bad(pud))
continue;
- if (check_pmd_range(vma, pud, addr, next, nodes))
+ if (check_pmd_range(vma, pud, addr, next, nodes,
+ flags, pagelist))
return -EIO;
} while (pud++, addr = next, addr != end);
return 0;
}
static inline int check_pgd_range(struct vm_area_struct *vma,
- unsigned long addr, unsigned long end, nodemask_t *nodes)
+ unsigned long addr, unsigned long end,
+ nodemask_t *nodes, unsigned long flags,
+ struct list_head *pagelist)
{
pgd_t *pgd;
unsigned long next;
@@ -252,16 +323,35 @@ static inline int check_pgd_range(struct
next = pgd_addr_end(addr, end);
if (pgd_none_or_clear_bad(pgd))
continue;
- if (check_pud_range(vma, pgd, addr, next, nodes))
+ if (check_pud_range(vma, pgd, addr, next, nodes,
+ flags, pagelist))
return -EIO;
} while (pgd++, addr = next, addr != end);
return 0;
}
-/* Step 1: check the range */
+/* Check if a vma is migratable */
+static inline int vma_migratable(struct vm_area_struct *vma)
+{
+ if (vma->vm_flags & (
+ VM_LOCKED |
+ VM_IO |
+ VM_RESERVED |
+ VM_DENYWRITE |
+ VM_SHM
+ ))
+ return 0;
+ return 1;
+}
+
+/*
+ * Check if all pages in a range are on a set of nodes.
+ * If pagelist != NULL then isolate pages from the LRU and
+ * put them on the pagelist.
+ */
static struct vm_area_struct *
check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
- nodemask_t *nodes, unsigned long flags)
+ nodemask_t *nodes, unsigned long flags, struct list_head *pagelist)
{
int err;
struct vm_area_struct *first, *vma, *prev;
@@ -273,17 +363,24 @@ check_range(struct mm_struct *mm, unsign
return ERR_PTR(-EACCES);
prev = NULL;
for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) {
- if (!vma->vm_next && vma->vm_end < end)
- return ERR_PTR(-EFAULT);
- if (prev && prev->vm_end < vma->vm_start)
- return ERR_PTR(-EFAULT);
- if ((flags & MPOL_MF_STRICT) && !is_vm_hugetlb_page(vma)) {
+ if (!(flags & MPOL_MF_DISCONTIG_OK)) {
+ if (!vma->vm_next && vma->vm_end < end)
+ return ERR_PTR(-EFAULT);
+ if (prev && prev->vm_end < vma->vm_start)
+ return ERR_PTR(-EFAULT);
+ }
+ if (!is_vm_hugetlb_page(vma) &&
+ ((flags & MPOL_MF_STRICT) ||
+ ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
+ vma_migratable(vma)
+ ))) {
unsigned long endvma = vma->vm_end;
if (endvma > end)
endvma = end;
if (vma->vm_start > start)
start = vma->vm_start;
- err = check_pgd_range(vma, start, endvma, nodes);
+ err = check_pgd_range(vma, start, endvma, nodes,
+ flags, pagelist);
if (err) {
first = ERR_PTR(err);
break;
@@ -357,33 +454,59 @@ long do_mbind(unsigned long start, unsig
struct mempolicy *new;
unsigned long end;
int err;
+ LIST_HEAD(pagelist);
- if ((flags & ~(unsigned long)(MPOL_MF_STRICT)) || mode > MPOL_MAX)
+ if ((flags & ~(unsigned long)(MPOL_MF_STRICT | MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
+ || mode > MPOL_MAX)
return -EINVAL;
+ if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_RESOURCE))
+ return -EPERM;
+
if (start & ~PAGE_MASK)
return -EINVAL;
+
if (mode == MPOL_DEFAULT)
flags &= ~MPOL_MF_STRICT;
+
len = (len + PAGE_SIZE - 1) & PAGE_MASK;
end = start + len;
+
if (end < start)
return -EINVAL;
if (end == start)
return 0;
+
if (mpol_check_policy(mode, nmask))
return -EINVAL;
+
new = mpol_new(mode, nmask);
if (IS_ERR(new))
return PTR_ERR(new);
+ /*
+ * If we are using the default policy then operation
+ * on discontinuous address spaces is okay after all
+ */
+ if (!new)
+ flags |= MPOL_MF_DISCONTIG_OK;
+
PDprintk("mbind %lx-%lx mode:%ld nodes:%lx\n",start,start+len,
mode,nodes_addr(nodes)[0]);
down_write(&mm->mmap_sem);
- vma = check_range(mm, start, end, nmask, flags);
+ vma = check_range(mm, start, end, nmask, flags,
+ (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) ? &pagelist : NULL);
err = PTR_ERR(vma);
- if (!IS_ERR(vma))
+ if (!IS_ERR(vma)) {
err = mbind_range(vma, start, end, new);
+ if (!list_empty(&pagelist))
+ migrate_pages(&pagelist, NULL);
+ if (!err && !list_empty(&pagelist) && (flags & MPOL_MF_STRICT))
+ err = -EIO;
+ }
+ if (!list_empty(&pagelist))
+ putback_lru_pages(&pagelist);
+
up_write(&mm->mmap_sem);
mpol_free(new);
return err;
Index: linux-2.6.14-rc5-mm1/include/linux/mempolicy.h
===================================================================
--- linux-2.6.14-rc5-mm1.orig/include/linux/mempolicy.h 2005-10-24 10:27:12.000000000 -0700
+++ linux-2.6.14-rc5-mm1/include/linux/mempolicy.h 2005-10-25 09:09:34.000000000 -0700
@@ -22,6 +22,8 @@
/* Flags for mbind */
#define MPOL_MF_STRICT (1<<0) /* Verify existing pages in the mapping */
+#define MPOL_MF_MOVE (1<<1) /* Move pages owned by this process to conform to mapping */
+#define MPOL_MF_MOVE_ALL (1<<2) /* Move every page to conform to mapping */
#ifdef __KERNEL__
Peter Zijlstra
> + if (rc == -1) { /* Not possible to isolate */
> + list_del(&page->lru);
> + list_add(&page->lru, src);
> }
Would the usage of list_move() not be simpler?
Peter Zijlstra
Christoph Lameter
> On Tue, 2005-10-25 at 12:30 -0700, Christoph Lameter wrote:
>
> > + if (rc == -1) { /* Not possible to isolate */
> > + list_del(&page->lru);
> > + list_add(&page->lru, src);
> > }
>
> Would the usage of list_move() not be simpler?
Hmmm. yes the whole section is a bit weird there (sorry Magnus). How
about this additional patch:
Index: linux-2.6.14-rc5-mm1/mm/vmscan.c
===================================================================
--- linux-2.6.14-rc5-mm1.orig/mm/vmscan.c 2005-10-25 08:09:52.000000000 -0700
+++ linux-2.6.14-rc5-mm1/mm/vmscan.c 2005-10-26 09:42:34.000000000 -0700
@@ -590,22 +590,22 @@ static int isolate_lru_pages(struct zone
{
struct page *page;
int scanned = 0;
- int rc;
while (scanned++ < nr_to_scan && !list_empty(src)) {
page = lru_to_page(src);
prefetchw_prev_lru_page(page, src, flags);
- rc = __isolate_lru_page(zone, page);
-
- BUG_ON(rc == 0); /* PageLRU(page) must be true */
-
- if (rc == 1) /* Succeeded to isolate page */
+ switch (__isolate_lru_page(zone, page)) {
+ case 1:
+ /* Succeeded to isolate page */
list_add(&page->lru, dst);
-
- if (rc == -1) { /* Not possible to isolate */
- list_del(&page->lru);
- list_add(&page->lru, src);
+ break;
+ case -1:
+ /* Not possible to isolate */
+ list_move(&page->lru, src);
+ break;
+ default:
+ BUG();