[prev in list] [next in list] [prev in thread] [next in thread]
List: linux-mm
Subject: [RFC][PATCH 4/6] mm: emergency pool and __GFP_EMERGENCY
From: Peter Zijlstra <a.p.zijlstra () chello ! nl>
Date: 2006-11-30 10:14:55
Message-ID: 20061130101921.854798000 () chello ! nl
[Download RAW message or body]
Introduce __GFP_EMERGENCY and an emergency pool.
__GFP_EMERGENCY will allow the allocation to disregard the watermarks,
much like PF_MEMALLOC. The emergency pool is separated from the min watermark
because ALLOC_HARDER and ALLOC_HIGH modify the watermark in a relative way
and thus do not ensure a strict minimum.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
include/linux/gfp.h | 7 ++++++-
include/linux/mmzone.h | 3 ++-
mm/internal.h | 10 +++++++---
mm/page_alloc.c | 48 +++++++++++++++++++++++++++++++++++++++++-------
mm/vmstat.c | 6 +++---
5 files changed, 59 insertions(+), 15 deletions(-)
Index: linux-2.6-git/include/linux/gfp.h
===================================================================
--- linux-2.6-git.orig/include/linux/gfp.h 2006-11-30 10:56:35.000000000 +0100
+++ linux-2.6-git/include/linux/gfp.h 2006-11-30 10:56:43.000000000 +0100
@@ -35,17 +35,21 @@ struct vm_area_struct;
#define __GFP_HIGH ((__force gfp_t)0x20u) /* Should access emergency pools? */
#define __GFP_IO ((__force gfp_t)0x40u) /* Can start physical IO? */
#define __GFP_FS ((__force gfp_t)0x80u) /* Can call down to low-level FS? */
+
#define __GFP_COLD ((__force gfp_t)0x100u) /* Cache-cold page required */
#define __GFP_NOWARN ((__force gfp_t)0x200u) /* Suppress page allocation failure warning */
#define __GFP_REPEAT ((__force gfp_t)0x400u) /* Retry the allocation. Might fail */
#define __GFP_NOFAIL ((__force gfp_t)0x800u) /* Retry for ever. Cannot fail */
+
#define __GFP_NORETRY ((__force gfp_t)0x1000u)/* Do not retry. Might fail */
#define __GFP_NO_GROW ((__force gfp_t)0x2000u)/* Slab internal usage */
#define __GFP_COMP ((__force gfp_t)0x4000u)/* Add compound page metadata */
#define __GFP_ZERO ((__force gfp_t)0x8000u)/* Return zeroed page on success */
+
#define __GFP_NOMEMALLOC ((__force gfp_t)0x10000u) /* Don't use emergency reserves */
#define __GFP_HARDWALL ((__force gfp_t)0x20000u) /* Enforce hardwall cpuset memory allocs */
#define __GFP_THISNODE ((__force gfp_t)0x40000u)/* No fallback, no policies */
+#define __GFP_EMERGENCY ((__force gfp_t)0x80000u) /* Use emergency reserves */
#define __GFP_BITS_SHIFT 20 /* Room for 20 __GFP_FOO bits */
#define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
@@ -54,7 +58,8 @@ struct vm_area_struct;
#define GFP_LEVEL_MASK (__GFP_WAIT|__GFP_HIGH|__GFP_IO|__GFP_FS| \
__GFP_COLD|__GFP_NOWARN|__GFP_REPEAT| \
__GFP_NOFAIL|__GFP_NORETRY|__GFP_NO_GROW|__GFP_COMP| \
- __GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_THISNODE)
+ __GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_THISNODE| \
+ __GFP_EMERGENCY)
/* This equals 0, but use constants in case they ever change */
#define GFP_NOWAIT (GFP_ATOMIC & ~__GFP_HIGH)
Index: linux-2.6-git/include/linux/mmzone.h
===================================================================
--- linux-2.6-git.orig/include/linux/mmzone.h 2006-11-30 10:56:35.000000000 +0100
+++ linux-2.6-git/include/linux/mmzone.h 2006-11-30 10:56:43.000000000 +0100
@@ -156,7 +156,7 @@ enum zone_type {
struct zone {
/* Fields commonly accessed by the page allocator */
unsigned long free_pages;
- unsigned long pages_min, pages_low, pages_high;
+ unsigned long pages_emerg, pages_min, pages_low, pages_high;
/*
* 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
@@ -461,6 +461,7 @@ int sysctl_min_unmapped_ratio_sysctl_han
struct file *, void __user *, size_t *, loff_t *);
int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
struct file *, void __user *, size_t *, loff_t *);
+void adjust_memalloc_reserve(int pages);
#include <linux/topology.h>
/* Returns the number of the current Node. */
Index: linux-2.6-git/mm/page_alloc.c
===================================================================
--- linux-2.6-git.orig/mm/page_alloc.c 2006-11-30 10:56:43.000000000 +0100
+++ linux-2.6-git/mm/page_alloc.c 2006-11-30 11:00:02.000000000 +0100
@@ -103,6 +103,7 @@ static char *zone_names[MAX_NR_ZONES] =
static DEFINE_SPINLOCK(min_free_lock);
int min_free_kbytes = 1024;
+int var_free_kbytes;
unsigned long __meminitdata nr_kernel_pages;
unsigned long __meminitdata nr_all_pages;
@@ -903,7 +904,8 @@ int zone_watermark_ok(struct zone *z, in
if (alloc_flags & ALLOC_HARDER)
min -= min / 4;
- if (free_pages <= min + z->lowmem_reserve[classzone_idx])
+ if (free_pages <= min + z->lowmem_reserve[classzone_idx] +
+ z->pages_emerg)
return 0;
for (o = 0; o < order; o++) {
/* At the next order, this order's pages become unavailable */
@@ -1344,9 +1346,9 @@ void show_free_areas(void)
"\n",
zone->name,
K(zone->free_pages),
- K(zone->pages_min),
- K(zone->pages_low),
- K(zone->pages_high),
+ K(zone->pages_emerg + zone->pages_min),
+ K(zone->pages_emerg + zone->pages_low),
+ K(zone->pages_emerg + zone->pages_high),
K(zone->nr_active),
K(zone->nr_inactive),
K(zone->present_pages),
@@ -2757,7 +2759,7 @@ static void calculate_totalreserve_pages
}
/* we treat pages_high as reserved pages. */
- max += zone->pages_high;
+ max += zone->pages_high + zone->pages_emerg;
if (max > zone->present_pages)
max = zone->present_pages;
@@ -2814,7 +2816,8 @@ static void setup_per_zone_lowmem_reserv
*/
static void __setup_per_zone_pages_min(void)
{
- unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
+ unsigned pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
+ unsigned pages_emerg = var_free_kbytes >> (PAGE_SHIFT - 10);
unsigned long lowmem_pages = 0;
struct zone *zone;
unsigned long flags;
@@ -2826,11 +2829,13 @@ static void __setup_per_zone_pages_min(v
}
for_each_zone(zone) {
- u64 tmp;
+ u64 tmp, tmp_emerg;
spin_lock_irqsave(&zone->lru_lock, flags);
tmp = (u64)pages_min * zone->present_pages;
do_div(tmp, lowmem_pages);
+ tmp_emerg = (u64)pages_emerg * zone->present_pages;
+ do_div(tmp_emerg, lowmem_pages);
if (is_highmem(zone)) {
/*
* __GFP_HIGH and PF_MEMALLOC allocations usually don't
@@ -2849,12 +2854,14 @@ static void __setup_per_zone_pages_min(v
if (min_pages > 128)
min_pages = 128;
zone->pages_min = min_pages;
+ zone->pages_emerg = min_pages;
} else {
/*
* If it's a lowmem zone, reserve a number of pages
* proportionate to the zone's size.
*/
zone->pages_min = tmp;
+ zone->pages_emerg = tmp_emerg;
}
zone->pages_low = zone->pages_min + (tmp >> 2);
@@ -2875,6 +2882,33 @@ void setup_per_zone_pages_min(void)
spin_unlock_irqrestore(&min_free_lock, flags);
}
+/**
+ * adjust_memalloc_reserve - adjust the memalloc reserve
+ * @pages: number of pages to add
+ *
+ * It adds a number of pages to the memalloc reserve; if
+ * the number was positive it kicks kswapd into action to
+ * satisfy the higher watermarks.
+ *
+ * NOTE: there is only a single caller, hence no locking.
+ */
+void adjust_memalloc_reserve(int pages)
+{
+ var_free_kbytes += pages << (PAGE_SHIFT - 10);
+ BUG_ON(var_free_kbytes < 0);
+ setup_per_zone_pages_min();
+ if (pages > 0) {
+ struct zone *zone;
+ for_each_zone(zone)
+ wakeup_kswapd(zone, 0);
+ }
+ if (pages)
+ printk(KERN_DEBUG "Emergency reserve: %d\n",
+ var_free_kbytes);
+}
+
+EXPORT_SYMBOL_GPL(adjust_memalloc_reserve);
+
/*
* Initialise min_free_kbytes.
*
Index: linux-2.6-git/mm/vmstat.c
===================================================================
--- linux-2.6-git.orig/mm/vmstat.c 2006-11-30 10:56:35.000000000 +0100
+++ linux-2.6-git/mm/vmstat.c 2006-11-30 11:00:42.000000000 +0100
@@ -535,9 +535,9 @@ static int zoneinfo_show(struct seq_file
"\n spanned %lu"
"\n present %lu",
zone->free_pages,
- zone->pages_min,
- zone->pages_low,
- zone->pages_high,
+ zone->pages_emerg + zone->pages_min,
+ zone->pages_emerg + zone->pages_low,
+ zone->pages_emerg + zone->pages_high,
zone->nr_active,
zone->nr_inactive,
zone->pages_scanned,
Index: linux-2.6-git/mm/internal.h
===================================================================
--- linux-2.6-git.orig/mm/internal.h 2006-11-30 10:56:43.000000000 +0100
+++ linux-2.6-git/mm/internal.h 2006-11-30 10:56:43.000000000 +0100
@@ -75,7 +75,9 @@ static int inline gfp_to_alloc_flags(gfp
alloc_flags |= ALLOC_HARDER;
if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
- if (!in_irq() && (p->flags & PF_MEMALLOC))
+ if (gfp_mask & __GFP_EMERGENCY)
+ alloc_flags |= ALLOC_NO_WATERMARKS;
+ else if (!in_irq() && (p->flags & PF_MEMALLOC))
alloc_flags |= ALLOC_NO_WATERMARKS;
else if (!in_interrupt() &&
unlikely(test_thread_flag(TIF_MEMDIE)))
@@ -103,7 +105,7 @@ static inline int alloc_flags_to_rank(in
return rank;
}
-static inline int gfp_to_rank(gfp_t gfp_mask)
+static __always_inline int gfp_to_rank(gfp_t gfp_mask)
{
/*
* Although correct this full version takes a ~3% performance
@@ -118,7 +120,9 @@ static inline int gfp_to_rank(gfp_t gfp_
*/
if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
- if (!in_irq() && (current->flags & PF_MEMALLOC))
+ if (gfp_mask & __GFP_EMERGENCY)
+ return 0;
+ else if (!in_irq() && (current->flags & PF_MEMALLOC))
return 0;
else if (!in_interrupt() &&
unlikely(test_thread_flag(TIF_MEMDIE)))
--
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
[prev in list] [next in list] [prev in thread] [next in thread]
Configure |
About |
News |
Add a list |
Sponsored by KoreLogic