On Sun, Nov 18, 2001 at 09:24:34AM +0100, Andrea Arcangeli wrote:
> If all works right on Monday I will port the fix to mainline (it's
Ok here it is against 2.4.15pre6:
ftp://ftp.us.kernel.org/pub/linux/kernel/people/andrea/patches/v2.4/2.4.15pre6/zone-watermarks-1
(also attached to the email). Untested on top of mainline but should be
safe to apply. also avoids GFP_ATOMIC from interrupts to eat the
PF_MEMALLOC (longstanding fix from Manfred).
Andrea
--Md/poaVZ8hnGTzuv
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment; filename=zone-watermarks-1
diff -urN 2.4.15pre6/include/linux/mmzone.h google/include/linux/mmzone.h
--- 2.4.15pre6/include/linux/mmzone.h Tue Nov 13 05:18:58 2001
+++ google/include/linux/mmzone.h Mon Nov 19 18:19:00 2001
@@ -18,6 +18,11 @@
#define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
#endif
+#define ZONE_DMA 0
+#define ZONE_NORMAL 1
+#define ZONE_HIGHMEM 2
+#define MAX_NR_ZONES 3
+
typedef struct free_area_struct {
struct list_head free_list;
unsigned long *map;
@@ -25,6 +30,10 @@
struct pglist_data;
+typedef struct zone_watermarks_s {
+ unsigned long min, low, high;
+} zone_watermarks_t;
+
/*
* On machines where it is needed (eg PCs) we divide physical memory
* into multiple physical zones. On a PC we have 3 zones:
@@ -39,8 +48,17 @@
*/
spinlock_t lock;
unsigned long free_pages;
- unsigned long pages_min, pages_low, pages_high;
- int need_balance;
+
+ /*
+ * We don't know if the memory that we're going to allocate will be freeable
+ * or/and it will be released eventually, so to avoid totally wasting several
+ * GB of ram we must reserve some of the lower zone memory (otherwise we risk
+ * to run OOM on the lower zones despite there's tons of freeable ram
+ * on the higher zones).
+ */
+ zone_watermarks_t watermarks[MAX_NR_ZONES];
+
+ unsigned long need_balance;
/*
* free areas of different sizes
@@ -60,6 +78,7 @@
*/
char *name;
unsigned long size;
+ unsigned long realsize;
} zone_t;
#define ZONE_DMA 0
@@ -113,8 +132,8 @@
extern int numnodes;
extern pg_data_t *pgdat_list;
-#define memclass(pgzone, classzone) (((pgzone)->zone_pgdat == (classzone)->zone_pgdat) \
- && ((pgzone) <= (classzone)))
+#define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones)
+#define memclass(pgzone, classzone) (zone_idx(pgzone) <= zone_idx(classzone))
/*
* The following two are not meant for general usage. They are here as
diff -urN 2.4.15pre6/mm/page_alloc.c google/mm/page_alloc.c
--- 2.4.15pre6/mm/page_alloc.c Sun Nov 18 06:04:47 2001
+++ google/mm/page_alloc.c Mon Nov 19 18:09:15 2001
@@ -27,9 +27,10 @@
pg_data_t *pgdat_list;
static char *zone_names[MAX_NR_ZONES] = { "DMA", "Normal", "HighMem" };
-static int zone_balance_ratio[MAX_NR_ZONES] __initdata = { 32, 128, 128, };
+static int zone_balance_ratio[MAX_NR_ZONES] __initdata = { 128, 128, 128, };
static int zone_balance_min[MAX_NR_ZONES] __initdata = { 20 , 20, 20, };
static int zone_balance_max[MAX_NR_ZONES] __initdata = { 255 , 255, 255, };
+static int lower_zone_reserve_ratio[MAX_NR_ZONES-1] = { 128, 8 };
/*
* Free_page() adds the page to the free lists. This is optimized for
@@ -312,16 +313,18 @@
{
zone_t **zone, * classzone;
struct page * page;
- int freed;
+ int freed, class_idx;
zone = zonelist->zones;
classzone = *zone;
+ class_idx = zone_idx(classzone);
+
for (;;) {
zone_t *z = *(zone++);
if (!z)
break;
- if (zone_free_pages(z, order) > z->pages_low) {
+ if (zone_free_pages(z, order) > z->watermarks[class_idx].low) {
page = rmqueue(z, order);
if (page)
return page;
@@ -340,7 +343,7 @@
if (!z)
break;
- min = z->pages_min;
+ min = z->watermarks[class_idx].min;
if (!(gfp_mask & __GFP_WAIT))
min >>= 2;
if (zone_free_pages(z, order) > min) {
@@ -353,7 +356,7 @@
/* here we're in the low on memory slow path */
rebalance:
- if (current->flags & (PF_MEMALLOC | PF_MEMDIE)) {
+ if (current->flags & (PF_MEMALLOC | PF_MEMDIE) && !in_interrupt()) {
zone = zonelist->zones;
for (;;) {
zone_t *z = *(zone++);
@@ -381,7 +384,7 @@
if (!z)
break;
- if (zone_free_pages(z, order) > z->pages_min) {
+ if (zone_free_pages(z, order) > z->watermarks[class_idx].min) {
page = rmqueue(z, order);
if (page)
return page;
@@ -473,13 +476,15 @@
unsigned int sum = 0;
do {
+ int class_idx;
zonelist_t *zonelist = pgdat->node_zonelists + (GFP_USER & GFP_ZONEMASK);
zone_t **zonep = zonelist->zones;
zone_t *zone;
+ class_idx = zone_idx(*zonep);
for (zone = *zonep++; zone; zone = *zonep++) {
unsigned long size = zone->size;
- unsigned long high = zone->pages_high;
+ unsigned long high = zone->watermarks[class_idx].high;
if (size > high)
sum += size - high;
}
@@ -525,13 +530,9 @@
zone_t *zone;
for (zone = tmpdat->node_zones;
zone < tmpdat->node_zones + MAX_NR_ZONES; zone++)
- printk("Zone:%s freepages:%6lukB min:%6lukB low:%6lukB "
- "high:%6lukB\n",
+ printk("Zone:%s freepages:%6lukB\n",
zone->name,
- K(zone->free_pages),
- K(zone->pages_min),
- K(zone->pages_low),
- K(zone->pages_high));
+ K(zone->free_pages));
tmpdat = tmpdat->node_next;
}
@@ -697,6 +698,7 @@
zone_t *zone = pgdat->node_zones + j;
unsigned long mask;
unsigned long size, realsize;
+ int idx;
realsize = size = zones_size[j];
if (zholes_size)
@@ -704,6 +706,7 @@
printk("zone(%lu): %lu pages.\n", j, size);
zone->size = size;
+ zone->realsize = realsize;
zone->name = zone_names[j];
zone->lock = SPIN_LOCK_UNLOCKED;
zone->zone_pgdat = pgdat;
@@ -719,9 +722,29 @@
mask = zone_balance_min[j];
else if (mask > zone_balance_max[j])
mask = zone_balance_max[j];
- zone->pages_min = mask;
- zone->pages_low = mask*2;
- zone->pages_high = mask*3;
+ zone->watermarks[j].min = mask;
+ zone->watermarks[j].low = mask*2;
+ zone->watermarks[j].high = mask*3;
+ /* now set the watermarks of the lower zones in the "j" classzone */
+ for (idx = j-1; idx >= 0; idx--) {
+ zone_t * lower_zone = pgdat->node_zones + idx;
+ unsigned long lower_zone_reserve;
+ if (!lower_zone->size)
+ continue;
+
+ mask = lower_zone->watermarks[idx].min;
+ lower_zone->watermarks[j].min = mask;
+ lower_zone->watermarks[j].low = mask*2;
+ lower_zone->watermarks[j].high = mask*3;
+
+ /* now the brainer part */
+ lower_zone_reserve = realsize / lower_zone_reserve_ratio[idx];
+ lower_zone->watermarks[j].min += lower_zone_reserve;
+ lower_zone->watermarks[j].low += lower_zone_reserve;
+ lower_zone->watermarks[j].high += lower_zone_reserve;
+
+ realsize += lower_zone->realsize;
+ }
zone->zone_mem_map = mem_map + offset;
zone->zone_start_mapnr = offset;
@@ -797,3 +820,16 @@
}
__setup("memfrac=", setup_mem_frac);
+
+static int __init setup_lower_zone_reserve(char *str)
+{
+ int j = 0;
+
+ while (get_option(&str, &lower_zone_reserve_ratio[j++]) == 2);
+ printk("setup_lower_zone_reserve: ");
+ for (j = 0; j < MAX_NR_ZONES-1; j++) printk("%d ", lower_zone_reserve_ratio[j]);
+ printk("\n");
+ return 1;
+}
+
+__setup("lower_zone_reserve=", setup_lower_zone_reserve);
diff -urN 2.4.15pre6/mm/vmscan.c google/mm/vmscan.c
--- 2.4.15pre6/mm/vmscan.c Sun Nov 18 06:04:47 2001
+++ google/mm/vmscan.c Mon Nov 19 18:10:19 2001
@@ -606,11 +606,12 @@
static int check_classzone_need_balance(zone_t * classzone)
{
- zone_t * first_classzone;
+ zone_t * first_zone;
+ int class_idx = zone_idx(classzone);
- first_classzone = classzone->zone_pgdat->node_zones;
- while (classzone >= first_classzone) {
- if (classzone->free_pages > classzone->pages_high)
+ first_zone = classzone->zone_pgdat->node_zones;
+ while (classzone >= first_zone) {
+ if (classzone->free_pages > classzone->watermarks[class_idx].high)
return 0;
classzone--;
}
--Md/poaVZ8hnGTzuv--
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