The following patch (against 2.4.6-ac2, already merged in 2.4.6-ac3) adds
specific perzone inactive/free shortage handling code.
This avoids us from freeing/deactivating pages from all zones in case
there are only zone-specific free or inactive shortages.
Its not _strict_ perzone handling: we still have the global free/inactive
shortage handling.
This fixes most of the highmem problems (I'm not able to deadlock a 4GB
machine running memory-intensive programs with the patch anymore. I've
also received one success report from Dirk Wetter running two 2GB
simulations on a 4GB machine).
In case you don't have any objections against the patch I'll generate
it against the latest 2.4.7-pre for inclusion.
Please read it,
diff --exclude-from=/home/marcelo/exclude -Nur linux.orig/include/linux/swap.h linux/include/linux/swap.h
--- linux.orig/include/linux/swap.h Sat Jul 14 02:47:14 2001
+++ linux/include/linux/swap.h Sat Jul 14 03:27:13 2001
@@ -123,9 +123,14 @@
extern wait_queue_head_t kreclaimd_wait;
extern int page_launder(int, int);
extern int free_shortage(void);
+extern int total_free_shortage(void);
extern int inactive_shortage(void);
+extern int total_inactive_shortage(void);
extern void wakeup_kswapd(void);
extern int try_to_free_pages(unsigned int gfp_mask);
+
+extern unsigned int zone_free_shortage(zone_t *zone);
+extern unsigned int zone_inactive_shortage(zone_t *zone);
/* linux/mm/page_io.c */
extern void rw_swap_page(int, struct page *);
diff --exclude-from=/home/marcelo/exclude -Nur linux.orig/mm/page_alloc.c linux/mm/page_alloc.c
--- linux.orig/mm/page_alloc.c Sat Jul 14 02:47:14 2001
+++ linux/mm/page_alloc.c Sat Jul 14 02:50:50 2001
@@ -451,7 +451,7 @@
* to give up than to deadlock the kernel looping here.
*/
if (gfp_mask & __GFP_WAIT) {
- if (!order || free_shortage()) {
+ if (!order || total_free_shortage()) {
int progress = try_to_free_pages(gfp_mask);
if (progress || (gfp_mask & __GFP_FS))
goto try_again;
@@ -689,6 +689,39 @@
return pages;
}
#endif
+
+unsigned int zone_free_shortage(zone_t *zone)
+{
+ int sum = 0;
+
+ if (!zone->size)
+ goto ret;
+
+ if (zone->inactive_clean_pages + zone->free_pages
+ < zone->pages_min) {
+ sum += zone->pages_min;
+ sum -= zone->free_pages;
+ sum -= zone->inactive_clean_pages;
+ }
+ret:
+ return sum;
+}
+
+unsigned int zone_inactive_shortage(zone_t *zone)
+{
+ int sum = 0;
+
+ if (!zone->size)
+ goto ret;
+
+ sum = zone->pages_high;
+ sum -= zone->inactive_dirty_pages;
+ sum -= zone->inactive_clean_pages;
+ sum -= zone->free_pages;
+
+ret:
+ return (sum > 0 ? sum : 0);
+}
/*
* Show free area list (used inside shift_scroll-lock stuff)
diff --exclude-from=/home/marcelo/exclude -Nur linux.orig/mm/vmscan.c linux/mm/vmscan.c
--- linux.orig/mm/vmscan.c Sat Jul 14 02:47:14 2001
+++ linux/mm/vmscan.c Sat Jul 14 03:22:19 2001
@@ -36,11 +36,19 @@
*/
/* mm->page_table_lock is held. mmap_sem is not held */
-static void try_to_swap_out(struct mm_struct * mm, struct vm_area_struct* vma, unsigned long address, pte_t * page_table, struct page *page)
+static void try_to_swap_out(zone_t *zone, struct mm_struct * mm, struct vm_area_struct* vma, unsigned long address, pte_t * page_table, struct page *page)
{
pte_t pte;
swp_entry_t entry;
+ /*
+ * If we are doing a zone-specific scan, do not
+ * touch pages from zones which don't have a
+ * shortage.
+ */
+ if (zone && !zone_inactive_shortage(page->zone))
+ return;
+
/* Don't look at this pte if it's been accessed recently. */
if (ptep_test_and_clear_young(page_table)) {
page->age += PAGE_AGE_ADV;
@@ -131,7 +139,7 @@
}
/* mm->page_table_lock is held. mmap_sem is not held */
-static int swap_out_pmd(struct mm_struct * mm, struct vm_area_struct * vma, pmd_t *dir, unsigned long address, unsigned long end, int count)
+static int swap_out_pmd(zone_t *zone, struct mm_struct * mm, struct vm_area_struct * vma, pmd_t *dir, unsigned long address, unsigned long end, int count)
{
pte_t * pte;
unsigned long pmd_end;
@@ -155,7 +163,7 @@
struct page *page = pte_page(*pte);
if (VALID_PAGE(page) && !PageReserved(page)) {
- try_to_swap_out(mm, vma, address, pte, page);
+ try_to_swap_out(zone, mm, vma, address, pte, page);
if (!--count)
break;
}
@@ -168,7 +176,7 @@
}
/* mm->page_table_lock is held. mmap_sem is not held */
-static inline int swap_out_pgd(struct mm_struct * mm, struct vm_area_struct * vma, pgd_t *dir, unsigned long address, unsigned long end, int count)
+static inline int swap_out_pgd(zone_t *zone, struct mm_struct * mm, struct vm_area_struct * vma, pgd_t *dir, unsigned long address, unsigned long end, int count)
{
pmd_t * pmd;
unsigned long pgd_end;
@@ -188,7 +196,7 @@
end = pgd_end;
do {
- count = swap_out_pmd(mm, vma, pmd, address, end, count);
+ count = swap_out_pmd(zone, mm, vma, pmd, address, end, count);
if (!count)
break;
address = (address + PMD_SIZE) & PMD_MASK;
@@ -198,7 +206,7 @@
}
/* mm->page_table_lock is held. mmap_sem is not held */
-static int swap_out_vma(struct mm_struct * mm, struct vm_area_struct * vma, unsigned long address, int count)
+static int swap_out_vma(zone_t *zone, struct mm_struct * mm, struct vm_area_struct * vma, unsigned long address, int count)
{
pgd_t *pgdir;
unsigned long end;
@@ -213,7 +221,7 @@
if (address >= end)
BUG();
do {
- count = swap_out_pgd(mm, vma, pgdir, address, end, count);
+ count = swap_out_pgd(zone, mm, vma, pgdir, address, end, count);
if (!count)
break;
address = (address + PGDIR_SIZE) & PGDIR_MASK;
@@ -225,7 +233,7 @@
/*
* Returns non-zero if we scanned all `count' pages
*/
-static int swap_out_mm(struct mm_struct * mm, int count)
+static int swap_out_mm(zone_t *zone, struct mm_struct * mm, int count)
{
unsigned long address;
struct vm_area_struct* vma;
@@ -248,7 +256,7 @@
address = vma->vm_start;
for (;;) {
- count = swap_out_vma(mm, vma, address, count);
+ count = swap_out_vma(zone, mm, vma, address, count);
if (!count)
goto out_unlock;
vma = vma->vm_next;
@@ -280,7 +288,7 @@
return nr;
}
-static void swap_out(unsigned int priority, int gfp_mask)
+static void swap_out(zone_t *zone, unsigned int priority, int gfp_mask)
{
int counter;
int retval = 0;
@@ -288,7 +296,7 @@
/* Always start by trying to penalize the process that is allocating memory */
if (mm)
- retval = swap_out_mm(mm, swap_amount(mm));
+ retval = swap_out_mm(zone, mm, swap_amount(mm));
/* Then, look at the other mm's */
counter = (mmlist_nr << SWAP_MM_SHIFT) >> priority;
@@ -310,7 +318,7 @@
spin_unlock(&mmlist_lock);
/* Walk about 6% of the address space each time */
- retval |= swap_out_mm(mm, swap_amount(mm));
+ retval |= swap_out_mm(zone, mm, swap_amount(mm));
mmput(mm);
} while (--counter >= 0);
return;
@@ -426,7 +434,7 @@
#define MAX_LAUNDER (4 * (1 << page_cluster))
#define CAN_DO_FS (gfp_mask & __GFP_FS)
#define CAN_DO_IO (gfp_mask & __GFP_IO)
-int page_launder(int gfp_mask, int sync)
+int do_page_launder(zone_t *zone, int gfp_mask, int sync)
{
int launder_loop, maxscan, cleaned_pages, maxlaunder;
struct list_head * page_lru;
@@ -461,6 +469,17 @@
continue;
}
+ /*
+ * If we are doing zone-specific laundering,
+ * avoid touching pages from zones which do
+ * not have a free shortage.
+ */
+ if (zone && !zone_free_shortage(page->zone)) {
+ list_del(page_lru);
+ list_add(page_lru, &inactive_dirty_list);
+ continue;
+ }
+
/*
* The page is locked. IO in progress?
* Move it to the back of the list.
@@ -574,8 +593,13 @@
* If we're freeing buffer cache pages, stop when
* we've got enough free memory.
*/
- if (freed_page && !free_shortage())
- break;
+ if (freed_page) {
+ if (zone) {
+ if (!zone_free_shortage(zone))
+ break;
+ } else if (!free_shortage())
+ break;
+ }
continue;
} else if (page->mapping && !PageDirty(page)) {
/*
@@ -613,7 +637,8 @@
* loads, flush out the dirty pages before we have to wait on
* IO.
*/
- if (CAN_DO_IO && !launder_loop && free_shortage()) {
+ if (CAN_DO_IO && !launder_loop && (free_shortage()
+ || (zone && zone_free_shortage(zone)))) {
launder_loop = 1;
/* If we cleaned pages, never do synchronous IO. */
if (cleaned_pages)
@@ -629,6 +654,34 @@
return cleaned_pages;
}
+int page_launder(int gfp_mask, int sync)
+{
+ int type = 0;
+ int ret;
+ pg_data_t *pgdat = pgdat_list;
+ /*
+ * First do a global scan if there is a
+ * global shortage.
+ */
+ if (free_shortage())
+ ret += do_page_launder(NULL, gfp_mask, sync);
+
+ /*
+ * Then check if there is any specific zone
+ * needs laundering.
+ */
+ for (type = 0; type < MAX_NR_ZONES; type++) {
+ zone_t *zone = pgdat->node_zones + type;
+
+ if (zone_free_shortage(zone))
+ ret += do_page_launder(zone, gfp_mask, sync);
+ }
+
+ return ret;
+}
+
+
+
/**
* refill_inactive_scan - scan the active list and find pages to deactivate
* @priority: the priority at which to scan
@@ -637,7 +690,7 @@
* This function will scan a portion of the active list to find
* unused pages, those pages will then be moved to the inactive list.
*/
-int refill_inactive_scan(unsigned int priority, int target)
+int refill_inactive_scan(zone_t *zone, unsigned int priority, int target)
{
struct list_head * page_lru;
struct page * page;
@@ -665,6 +718,16 @@
continue;
}
+ /*
+ * If we are doing zone-specific scanning, ignore
+ * pages from zones without shortage.
+ */
+
+ if (zone && !zone_inactive_shortage(page->zone)) {
+ page_active = 1;
+ goto skip_page;
+ }
+
/* Do aging on the pages. */
if (PageTestandClearReferenced(page)) {
age_page_up_nolock(page);
@@ -694,6 +757,7 @@
* to the other end of the list. Otherwise we exit if
* we have done enough work.
*/
+skip_page:
if (page_active || PageActive(page)) {
list_del(page_lru);
list_add(page_lru, &active_list);
@@ -709,12 +773,10 @@
}
/*
- * Check if there are zones with a severe shortage of free pages,
- * or if all zones have a minor shortage.
+ * Check if we have are low on free pages globally.
*/
int free_shortage(void)
{
- pg_data_t *pgdat = pgdat_list;
int sum = 0;
int freeable = nr_free_pages() + nr_inactive_clean_pages();
int freetarget = freepages.high;
@@ -722,6 +784,22 @@
/* Are we low on free pages globally? */
if (freeable < freetarget)
return freetarget - freeable;
+ return 0;
+}
+
+/*
+ *
+ * Check if there are zones with a severe shortage of free pages,
+ * or if all zones have a minor shortage.
+ */
+int total_free_shortage(void)
+{
+ int sum = 0;
+ pg_data_t *pgdat = pgdat_list;
+
+ /* Do we have a global free shortage? */
+ if((sum = free_shortage()))
+ return sum;
/* If not, are we very low on any particular zone? */
do {
@@ -739,15 +817,15 @@
} while (pgdat);
return sum;
+
}
/*
- * How many inactive pages are we short?
+ * How many inactive pages are we short globally?
*/
int inactive_shortage(void)
{
int shortage = 0;
- pg_data_t *pgdat = pgdat_list;
/* Is the inactive dirty list too small? */
@@ -759,10 +837,20 @@
if (shortage > 0)
return shortage;
+ return 0;
+}
+/*
+ * Are we low on inactive pages globally or in any zone?
+ */
+int total_inactive_shortage(void)
+{
+ int shortage = 0;
+ pg_data_t *pgdat = pgdat_list;
- /* If not, do we have enough per-zone pages on the inactive list? */
+ if((shortage = inactive_shortage()))
+ return shortage;
- shortage = 0;
+ shortage = 0;
do {
int i;
@@ -802,7 +890,7 @@
* when called from a user process.
*/
#define DEF_PRIORITY (6)
-static int refill_inactive(unsigned int gfp_mask, int user)
+static int refill_inactive_global(unsigned int gfp_mask, int user)
{
int count, start_count, maxtry;
@@ -824,9 +912,9 @@
}
/* Walk the VM space for a bit.. */
- swap_out(DEF_PRIORITY, gfp_mask);
+ swap_out(NULL, DEF_PRIORITY, gfp_mask);
- count -= refill_inactive_scan(DEF_PRIORITY, count);
+ count -= refill_inactive_scan(NULL, DEF_PRIORITY, count);
if (count <= 0)
goto done;
@@ -839,6 +927,60 @@
return (count < start_count);
}
+static int refill_inactive_zone(zone_t *zone, unsigned int gfp_mask, int user)
+{
+ int count, start_count, maxtry;
+
+ count = start_count = zone_inactive_shortage(zone);
+
+ maxtry = (1 << DEF_PRIORITY);
+
+ do {
+ swap_out(zone, DEF_PRIORITY, gfp_mask);
+
+ count -= refill_inactive_scan(zone, DEF_PRIORITY, count);
+
+ if (count <= 0)
+ goto done;
+
+ if (--maxtry <= 0)
+ return 0;
+
+ } while(zone_inactive_shortage(zone));
+done:
+ return (count < start_count);
+}
+
+
+static int refill_inactive(unsigned int gfp_mask, int user)
+{
+ int type = 0;
+ int ret;
+ pg_data_t *pgdat = pgdat_list;
+ /*
+ * First do a global scan if there is a
+ * global shortage.
+ */
+ if (inactive_shortage())
+ ret += refill_inactive_global(gfp_mask, user);
+
+ /*
+ * Then check if there is any specific zone
+ * with a shortage and try to refill it if
+ * so.
+ */
+ for (type = 0; type < MAX_NR_ZONES; type++) {
+ zone_t *zone = pgdat->node_zones + type;
+
+ if (zone_inactive_shortage(zone))
+ ret += refill_inactive_zone(zone, gfp_mask, user);
+ }
+
+ return ret;
+}
+
+#define DEF_PRIORITY (6)
+
static int do_try_to_free_pages(unsigned int gfp_mask, int user)
{
int ret = 0;
@@ -851,8 +993,10 @@
* before we get around to moving them to the other
* list, so this is a relatively cheap operation.
*/
- if (free_shortage()) {
- ret += page_launder(gfp_mask, user);
+
+ ret += page_launder(gfp_mask, user);
+
+ if (total_free_shortage()) {
shrink_dcache_memory(DEF_PRIORITY, gfp_mask);
shrink_icache_memory(DEF_PRIORITY, gfp_mask);
}
@@ -861,8 +1005,7 @@
* If needed, we move pages from the active list
* to the inactive list.
*/
- if (inactive_shortage())
- ret += refill_inactive(gfp_mask, user);
+ ret += refill_inactive(gfp_mask, user);
/*
* Reclaim unused slab cache if memory is low.
@@ -917,7 +1060,7 @@
static long recalc = 0;
/* If needed, try to free some memory. */
- if (inactive_shortage() || free_shortage())
+ if (total_inactive_shortage() || total_free_shortage())
do_try_to_free_pages(GFP_KSWAPD, 0);
/* Once a second ... */
@@ -928,7 +1071,7 @@
recalculate_vm_stats();
/* Do background page aging. */
- refill_inactive_scan(DEF_PRIORITY, 0);
+ refill_inactive_scan(NULL, DEF_PRIORITY, 0);
}
run_task_queue(&tq_disk);
@@ -944,7 +1087,7 @@
* We go to sleep for one second, but if it's needed
* we'll be woken up earlier...
*/
- if (!free_shortage() || !inactive_shortage()) {
+ if (!total_free_shortage() || !total_inactive_shortage()) {
interruptible_sleep_on_timeout(&kswapd_wait, HZ);
/*
* If we couldn't free enough memory, we see if it was
-
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