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SubjectRe: [with-PATCH-really] highmem deadlock removal, balancing & cleanup
On Sat, 26 May 2001, Andrea Arcangeli wrote:

> Please merge this one in 2.4 for now (originally from Ingo, I only
> improved it), this is a real definitive fix and there's no nicer way to
> handle that unless you want to generalize an API for people to generate
> private anti-deadlock ("make sure to always make a progress") memory
> pools:

Alternatively, the following might be more interesting...

-ben

diff --exclude=.* --exclude=*.[^ch]* -urN kernel-2.4.3-works/linux.orig/arch/i386/kernel/irq.c linux-toolbox-current/arch/i386/kernel/irq.c
--- kernel-2.4.3-works/linux.orig/arch/i386/kernel/irq.c Thu May 10 16:04:39 2001
+++ linux-toolbox-current/arch/i386/kernel/irq.c Thu May 10 12:16:21 2001
@@ -32,6 +32,7 @@
#include <linux/kernel_stat.h>
#include <linux/irq.h>
#include <linux/proc_fs.h>
+#include <linux/mm/reservation.h>

#include <asm/atomic.h>
#include <asm/io.h>
@@ -576,7 +577,10 @@
irq_desc_t *desc = irq_desc + irq;
struct irqaction * action;
unsigned int status;
+ struct page_reservation *saved_irq_rsv;

+ saved_irq_rsv = current->page_reservations;
+ current->page_reservations = &irq_rsv;
kstat.irqs[cpu][irq]++;
spin_lock(&desc->lock);
desc->handler->ack(irq);
@@ -638,6 +642,7 @@

if (softirq_active(cpu) & softirq_mask(cpu))
do_softirq();
+ current->page_reservations = saved_irq_rsv;
return 1;
}

diff --exclude=.* --exclude=*.[^ch]* -urN kernel-2.4.3-works/linux.orig/arch/i386/mm/fault.c linux-toolbox-current/arch/i386/mm/fault.c
--- kernel-2.4.3-works/linux.orig/arch/i386/mm/fault.c Thu May 10 16:04:40 2001
+++ linux-toolbox-current/arch/i386/mm/fault.c Mon May 14 13:26:57 2001
@@ -196,6 +196,7 @@
if (in_interrupt() || !mm)
goto no_context;

+ atomic_inc(&mm->in_fault_count);
down_read(&mm->mmap_sem);

vma = find_vma(mm, address);
@@ -269,6 +270,7 @@
if (bit < 32)
tsk->thread.screen_bitmap |= 1 << bit;
}
+ atomic_dec(&mm->in_fault_count);
up_read(&mm->mmap_sem);
return;

@@ -277,6 +279,7 @@
* Fix it, but check if it's kernel or user first..
*/
bad_area:
+ atomic_dec(&mm->in_fault_count);
up_read(&mm->mmap_sem);

bad_area_nosemaphore:
@@ -339,6 +342,7 @@
* us unable to handle the page fault gracefully.
*/
out_of_memory:
+ atomic_dec(&mm->in_fault_count);
up_read(&mm->mmap_sem);
printk("VM: killing process %s\n", tsk->comm);
if (error_code & 4)
@@ -346,6 +350,7 @@
goto no_context;

do_sigbus:
+ atomic_dec(&mm->in_fault_count);
up_read(&mm->mmap_sem);

/*
diff --exclude=.* --exclude=*.[^ch]* -urN kernel-2.4.3-works/linux.orig/fs/buffer.c linux-toolbox-current/fs/buffer.c
--- kernel-2.4.3-works/linux.orig/fs/buffer.c Thu May 10 16:07:27 2001
+++ linux-toolbox-current/fs/buffer.c Fri May 11 16:42:19 2001
@@ -45,6 +45,7 @@
#include <linux/quotaops.h>
#include <linux/iobuf.h>
#include <linux/highmem.h>
+#include <linux/mm/reservation.h>

#include <asm/uaccess.h>
#include <asm/io.h>
@@ -2735,6 +2736,7 @@
*/
int bdflush(void *sem)
{
+ static struct page_reservation rsv;
struct task_struct *tsk = current;
int flushed;
/*
@@ -2748,6 +2750,12 @@
strcpy(tsk->comm, "bdflush");
bdflush_tsk = tsk;

+ init_page_reservation(&rsv, RSV_MULTISHOT, ZONE_NORMAL);
+ if (reserve_pages(&rsv, GFP_KERNEL, 64))
+ panic("bdflush unable to reserve emergency pages!\n");
+ tsk->page_reservations = &rsv;
+
+
/* avoid getting signals */
spin_lock_irq(&tsk->sigmask_lock);
flush_signals(tsk);
@@ -2778,6 +2786,8 @@
the next schedule will block. */
__set_current_state(TASK_RUNNING);
}
+
+ destroy_page_reservation(&rsv);
}

/*
@@ -2788,6 +2798,7 @@
*/
int kupdate(void *sem)
{
+ static struct page_reservation rsv;
struct task_struct * tsk = current;
int interval;

@@ -2795,6 +2806,11 @@
tsk->pgrp = 1;
strcpy(tsk->comm, "kupdated");

+ init_page_reservation(&rsv, RSV_MULTISHOT, ZONE_NORMAL);
+ if (reserve_pages(&rsv, GFP_KERNEL, 32))
+ panic("bdflush unable to reserve emergency pages!\n");
+ tsk->page_reservations = &rsv;
+
/* sigstop and sigcont will stop and wakeup kupdate */
spin_lock_irq(&tsk->sigmask_lock);
sigfillset(&tsk->blocked);
@@ -2833,6 +2849,7 @@
#endif
sync_old_buffers();
}
+ destroy_page_reservation(&rsv);
}

static int __init bdflush_init(void)
diff --exclude=.* --exclude=*.[^ch]* -urN kernel-2.4.3-works/linux.orig/include/linux/mm/reservation.h linux-toolbox-current/include/linux/mm/reservation.h
--- kernel-2.4.3-works/linux.orig/include/linux/mm/reservation.h Wed Dec 31 19:00:00 1969
+++ linux-toolbox-current/include/linux/mm/reservation.h Thu May 10 12:16:21 2001
@@ -0,0 +1,48 @@
+#ifndef __LINUX__MM__RESERVATION_H
+#define __LINUX__MM__RESERVATION_H
+/* inclinde/linux/mm/reservation.h
+ * written by Benjamin LaHaise
+ *
+ * Copyright 2001 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * based in part on ideas/code from Arjan Van de Ven and Stephen Tweedie.
+ */
+
+#define RSV_ONESHOT 0x00
+#define RSV_MULTISHOT 0x01 /* reservation will replenish itself */
+
+struct page_reservation {
+ struct list_head list;
+ unsigned avail, used;
+ int flags;
+ zone_t *zone;
+};
+
+extern struct page_reservation irq_rsv;
+
+extern void init_page_reservation(struct page_reservation *rsv, int flags, int zone);
+extern void destroy_page_reservation(struct page_reservation *rsv);
+
+/* Reservation is an all or nothing thing. A successful reservation
+ * returns 0. Anything else is a failure.
+ */
+extern int reserve_pages(struct page_reservation *rsv, int gfp_mask, unsigned count);
+
+/* Release a previously reserved amount of memory. */
+extern void put_reserved_pages(struct page_reservation *rsv, unsigned count);
+
+#endif
diff --exclude=.* --exclude=*.[^ch]* -urN kernel-2.4.3-works/linux.orig/include/linux/mm.h linux-toolbox-current/include/linux/mm.h
--- kernel-2.4.3-works/linux.orig/include/linux/mm.h Thu May 10 16:04:40 2001
+++ linux-toolbox-current/include/linux/mm.h Mon May 14 13:33:43 2001
@@ -528,7 +528,7 @@


#define GFP_BOUNCE (__GFP_HIGH | __GFP_FAIL)
-#define GFP_BUFFER (__GFP_HIGH | __GFP_WAIT)
+#define GFP_BUFFER (__GFP_HIGH | __GFP_WAIT | __GFP_FAIL)
#define GFP_ATOMIC (__GFP_HIGH)
#define GFP_USER ( __GFP_WAIT | __GFP_IO)
#define GFP_HIGHUSER ( __GFP_WAIT | __GFP_IO | __GFP_HIGHMEM)
diff --exclude=.* --exclude=*.[^ch]* -urN kernel-2.4.3-works/linux.orig/include/linux/mmzone.h linux-toolbox-current/include/linux/mmzone.h
--- kernel-2.4.3-works/linux.orig/include/linux/mmzone.h Thu May 10 16:07:27 2001
+++ linux-toolbox-current/include/linux/mmzone.h Fri May 11 20:46:13 2001
@@ -50,6 +50,10 @@
unsigned long inactive_dirty_pages;
unsigned long pages_min, pages_low, pages_high;

+ /* Page reservation */
+ unsigned long reserved_pages;
+ struct list_head depleted_rsv_list;
+
/*
* free areas of different sizes
*/
diff --exclude=.* --exclude=*.[^ch]* -urN kernel-2.4.3-works/linux.orig/include/linux/sched.h linux-toolbox-current/include/linux/sched.h
--- kernel-2.4.3-works/linux.orig/include/linux/sched.h Thu May 10 16:07:27 2001
+++ linux-toolbox-current/include/linux/sched.h Mon May 14 13:23:55 2001
@@ -210,6 +210,7 @@
pgd_t * pgd;
atomic_t mm_users; /* How many users with user space? */
atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
+ atomic_t in_fault_count; /* number of in progress page faults */
int map_count; /* number of VMAs */
struct rw_semaphore mmap_sem;
spinlock_t page_table_lock; /* Protects task page tables and mm->rss */
@@ -241,6 +242,7 @@
pgd: swapper_pg_dir, \
mm_users: ATOMIC_INIT(2), \
mm_count: ATOMIC_INIT(1), \
+ in_fault_count: ATOMIC_INIT(0), \
map_count: 1, \
mmap_sem: __RWSEM_INITIALIZER(name.mmap_sem), \
page_table_lock: SPIN_LOCK_UNLOCKED, \
@@ -406,6 +408,8 @@
u32 self_exec_id;
/* Protection of (de-)allocation: mm, files, fs, tty */
spinlock_t alloc_lock;
+
+ struct page_reservation *page_reservations;
};

/*
@@ -486,7 +490,8 @@
sig: &init_signals, \
pending: { NULL, &tsk.pending.head, {{0}}}, \
blocked: {{0}}, \
- alloc_lock: SPIN_LOCK_UNLOCKED \
+ alloc_lock: SPIN_LOCK_UNLOCKED, \
+ page_reservations: NULL, \
}


diff --exclude=.* --exclude=*.[^ch]* -urN kernel-2.4.3-works/linux.orig/init/main.c linux-toolbox-current/init/main.c
--- kernel-2.4.3-works/linux.orig/init/main.c Thu May 10 16:04:39 2001
+++ linux-toolbox-current/init/main.c Thu May 10 21:00:20 2001
@@ -28,6 +28,7 @@
#include <linux/iobuf.h>
#include <linux/bootmem.h>
#include <linux/tty.h>
+#include <linux/mm/reservation.h>

#include <asm/io.h>
#include <asm/bugs.h>
@@ -88,6 +89,9 @@

static int init(void *);

+extern struct page_reservation atomic_rsv;
+extern struct page_reservation swap_rsv;
+
extern void init_IRQ(void);
extern void init_modules(void);
extern void sock_init(void);
@@ -654,6 +658,13 @@
proc_root_init();
#endif
mempages = num_physpages;
+
+ if (reserve_pages(&irq_rsv, GFP_KERNEL, mempages >> 9))
+ panic("unable to reserve irq memory.\n");
+ if (reserve_pages(&swap_rsv, GFP_KERNEL, mempages >> 9))
+ panic("unable to reserve swap memory.\n");
+ if (reserve_pages(&atomic_rsv, GFP_KERNEL, mempages >> 10))
+ panic("unable to reserve atomic memory.\n");

fork_init(mempages);
proc_caches_init();
diff --exclude=.* --exclude=*.[^ch]* -urN kernel-2.4.3-works/linux.orig/kernel/exit.c linux-toolbox-current/kernel/exit.c
--- kernel-2.4.3-works/linux.orig/kernel/exit.c Thu May 10 16:07:27 2001
+++ linux-toolbox-current/kernel/exit.c Thu May 10 12:15:34 2001
@@ -10,6 +10,7 @@
#include <linux/smp_lock.h>
#include <linux/module.h>
#include <linux/tty.h>
+#include <linux/mm/reservation.h>
#ifdef CONFIG_BSD_PROCESS_ACCT
#include <linux/acct.h>
#endif
@@ -422,6 +423,11 @@
NORET_TYPE void do_exit(long code)
{
struct task_struct *tsk = current;
+
+ if (tsk->page_reservations) {
+ destroy_page_reservation(tsk->page_reservations);
+ tsk->page_reservations = NULL;
+ }

if (in_interrupt())
panic("Aiee, killing interrupt handler!");
diff --exclude=.* --exclude=*.[^ch]* -urN kernel-2.4.3-works/linux.orig/kernel/fork.c linux-toolbox-current/kernel/fork.c
--- kernel-2.4.3-works/linux.orig/kernel/fork.c Thu May 10 16:07:27 2001
+++ linux-toolbox-current/kernel/fork.c Mon May 14 13:24:45 2001
@@ -203,6 +203,7 @@
{
atomic_set(&mm->mm_users, 1);
atomic_set(&mm->mm_count, 1);
+ atomic_set(&mm->in_fault_count, 0);
init_rwsem(&mm->mmap_sem);
mm->page_table_lock = SPIN_LOCK_UNLOCKED;
mm->pgd = pgd_alloc();
@@ -630,6 +631,7 @@
p->tty_old_pgrp = 0;
p->times.tms_utime = p->times.tms_stime = 0;
p->times.tms_cutime = p->times.tms_cstime = 0;
+ p->page_reservations = 0;
#ifdef CONFIG_SMP
{
int i;
diff --exclude=.* --exclude=*.[^ch]* -urN kernel-2.4.3-works/linux.orig/mm/page_alloc.c linux-toolbox-current/mm/page_alloc.c
--- kernel-2.4.3-works/linux.orig/mm/page_alloc.c Thu May 10 16:07:27 2001
+++ linux-toolbox-current/mm/page_alloc.c Fri May 11 15:52:54 2001
@@ -18,7 +18,31 @@
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/slab.h>
+#include <linux/mm/reservation.h>

+extern int
+ page_launder_calls,
+ page_launder_scans,
+ page_launder_scanned_pages,
+ page_launder_scanned_not_dirty,
+ page_launder_scanned_active,
+ page_launder_scanned_skipped,
+ page_launder_scanned_dirty,
+ page_launder_scanned_dirty_skip,
+ page_launder_scanned_dirty_nolaunder,
+ page_launder_scanned_dirty_swapcache,
+ page_launder_scanned_buffers,
+ page_launder_scanned_buffers_refiled,
+ page_launder_scanned_buffers_freed_buffer,
+ page_launder_scanned_buffers_active,
+ page_launder_scanned_buffers_cleaned,
+ page_launder_scanned_buffers_released,
+ page_launder_scanned_mapped_clean,
+ page_launder_scanned_still_active
+;
+struct page_reservation atomic_rsv;
+struct page_reservation swap_rsv;
+struct page_reservation irq_rsv;
int nr_swap_pages;
int nr_active_pages;
int nr_inactive_dirty_pages;
@@ -99,7 +123,7 @@

page->flags &= ~((1<<PG_referenced) | (1<<PG_dirty));
page->age = PAGE_AGE_START;
-
+
zone = page->zone;

mask = (~0UL) << order;
@@ -115,7 +139,8 @@

__save_flags(flags);
__cli();
- if (!order && (per_cpu->nr_pages < per_cpu->max_nr_pages)) {
+ if (!order && (per_cpu->nr_pages < per_cpu->max_nr_pages) && list_empty(&zone->depleted_rsv_list)) {
+static int foo; if (foo++ < 5) printk("freeing per-cpu page\n");
list_add(&page->list, &per_cpu->head);
per_cpu->nr_pages++;
__restore_flags(flags);
@@ -124,6 +149,20 @@

spin_lock(&zone->lock);

+ /* Check if we need to replenish any of this zone's reservations. */
+ if (!list_empty(&zone->depleted_rsv_list)) {
+ struct page_reservation *rsv = list_entry(zone->depleted_rsv_list.next, struct page_reservation, list);
+static int foo; if (foo++ < 5) printk("updating reserve: %p %u %u\n", rsv, rsv->avail, rsv->used);
+ if (!rsv->used)
+ BUG();
+ rsv->avail++;
+ rsv->used--;
+
+ list_del_init(&rsv->list);
+ if (rsv->used)
+ list_add(&rsv->list, zone->depleted_rsv_list.prev);
+ }
+
zone->free_pages -= mask;

while (mask + (1 << (MAX_ORDER-1))) {
@@ -190,12 +229,13 @@
}


-static FASTCALL(struct page * rmqueue(zone_t *zone, unsigned long order));
-static struct page * rmqueue(zone_t *zone, unsigned long order)
+static FASTCALL(struct page * rmqueue(zone_t *zone, unsigned long order, struct page_reservation *rsv));
+static struct page * rmqueue(zone_t *zone, unsigned long order, struct page_reservation *rsv)
{
per_cpu_t *per_cpu = zone->cpu_pages + smp_processor_id();
free_area_t * area = zone->free_area + order;
unsigned long curr_order = order;
+ unsigned long free_pages;
struct list_head *head, *curr;
unsigned long flags;
struct page *page;
@@ -216,7 +256,15 @@
}

spin_lock(&zone->lock);
- do {
+
+ free_pages = zone->free_pages;
+ free_pages -= zone->reserved_pages;
+
+ /* Using a reservation? */
+ if (rsv)
+ free_pages += rsv->avail;
+
+ if (free_pages >= (1 << order)) do {
head = &area->free_list;
curr = memlist_next(head);

@@ -232,6 +280,16 @@
zone->free_pages -= 1 << order;

page = expand(zone, page, index, order, curr_order, area);
+ if (rsv && (rsv->avail >= (1 << order))) {
+static int foo; if (foo++ < 5) printk("alloc from reserv: %p %u %u\n", rsv, rsv->avail, rsv->used);
+ if (!rsv->used && (rsv->flags & RSV_MULTISHOT)) {
+static int foo; if (foo++ < 5) printk("multishot reserv: %p\n", rsv);
+ list_add(&rsv->list, &zone->depleted_rsv_list);
+ rsv->avail -= 1 << order;
+ rsv->used += 1 << order;
+}
+ zone->reserved_pages--;
+ }
spin_unlock_irqrestore(&zone->lock, flags);

set_page_count(page, 1);
@@ -265,6 +323,7 @@
for (;;) {
zone_t *z = *(zone++);
unsigned long water_mark;
+ unsigned long free_pages;

if (!z)
break;
@@ -275,6 +334,8 @@
* We allocate if the number of free + inactive_clean
* pages is above the watermark.
*/
+ free_pages = z->free_pages - z->reserved_pages;
+
switch (limit) {
default:
case PAGES_MIN:
@@ -287,14 +348,14 @@
water_mark = z->pages_high;
}

- if (z->free_pages + z->inactive_clean_pages > water_mark) {
+ if (free_pages + z->inactive_clean_pages > water_mark) {
struct page *page = NULL;
/* If possible, reclaim a page directly. */
- if (direct_reclaim && z->free_pages < z->pages_min + 8)
+ if (direct_reclaim && free_pages < z->pages_min + 8)
page = reclaim_page(z);
/* If that fails, fall back to rmqueue. */
if (!page)
- page = rmqueue(z, order);
+ page = rmqueue(z, order, NULL);
if (page)
return page;
}
@@ -304,6 +365,8 @@
return NULL;
}

+extern struct page *get_reserved_page (void);
+

/*
* This is the 'heart' of the zoned buddy allocator:
@@ -320,7 +383,7 @@
* Allocations put pressure on the VM subsystem.
*/
memory_pressure++;
-
+
/*
* (If anyone calls gfp from interrupts nonatomically then it
* will sooner or later tripped up by a schedule().)
@@ -351,11 +414,11 @@
if (!z->size)
BUG();

- if (z->free_pages >= z->pages_low) {
- page = rmqueue(z, order);
+ if (z->free_pages - z->reserved_pages >= z->pages_low) {
+ page = rmqueue(z, order, NULL);
if (page)
- return page;
- } else if (z->free_pages < z->pages_min &&
+ goto out_success;
+ } else if (z->free_pages - z->reserved_pages < z->pages_min &&
waitqueue_active(&kreclaimd_wait)) {
wake_up_interruptible(&kreclaimd_wait);
}
@@ -371,7 +434,7 @@
*/
page = __alloc_pages_limit(zonelist, order, PAGES_HIGH, direct_reclaim);
if (page)
- return page;
+ goto out_success;

/*
* Then try to allocate a page from a zone with more
@@ -383,7 +446,7 @@
*/
page = __alloc_pages_limit(zonelist, order, PAGES_LOW, direct_reclaim);
if (page)
- return page;
+ goto out_success;

/*
* OK, none of the zones on our zonelist has lots
@@ -418,8 +481,42 @@
*/
page = __alloc_pages_limit(zonelist, order, PAGES_MIN, direct_reclaim);
if (page)
- return page;
+ goto out_success;

+ /* Memory reservation hook. Note: memory reservations are
+ * attempted after all other normal means of allocations have
+ * failed. Give it a try with the memory reservation and see
+ * what happens.
+ * TODO: with memory reservations in place, much of the code
+ * below is completely bogus. Clean this up! -ben
+ */
+ if (current->page_reservations || (gfp_mask & __GFP_HIGH)) {
+ struct page_reservation *rsv;
+
+ if (gfp_mask & __GFP_HIGH)
+ rsv = &atomic_rsv;
+ else
+ rsv = current->page_reservations;
+
+ do {
+ zone = zonelist->zones;
+ for (;;) {
+ zone_t *z = *(zone++);
+ if (!z)
+ break;
+
+ if (z == rsv->zone) {
+static int foo; if (foo++ < 5) printk("trying reservation: %p\n", current->page_reservations);
+ page = rmqueue(z, order, rsv);
+ if (page)
+ goto out_success;
+ break;
+ }
+ }
+ } while (rsv == &atomic_rsv &&
+ (rsv = current->page_reservations));
+ }
+
/*
* If we dont want to try too hard then we can give up
* now
@@ -465,9 +562,9 @@
break;
__free_page(page);
/* Try if the allocation succeeds. */
- page = rmqueue(z, order);
+ page = rmqueue(z, order, NULL);
if (page)
- return page;
+ goto out_success;
}
}
}
@@ -485,6 +582,11 @@
memory_pressure++;
try_to_free_pages(gfp_mask);
wakeup_bdflush(0);
+ if ((gfp_mask & __GFP_WAIT) && !(current->flags & PF_ATOMICALLOC)) {
+ __set_current_state(TASK_RUNNING);
+ current->policy |= SCHED_YIELD;
+ schedule();
+ }
goto try_again;
}
}
@@ -511,31 +613,25 @@
if (direct_reclaim) {
page = reclaim_page(z);
if (page)
- return page;
+ goto out_success;
}

/* XXX: is pages_min/4 a good amount to reserve for this? */
- if (z->free_pages < z->pages_min / 4 &&
+ if (z->free_pages - z->reserved_pages < z->pages_min / 4 &&
!((current->flags & PF_MEMALLOC) &&
(gfp_mask & __GFP_WAIT)))
continue;
- page = rmqueue(z, order);
+ page = rmqueue(z, order, NULL);
if (page)
- return page;
+ goto out_success;
}

- // okay - we are in trouble, lets go to the DMA pool directly:
-
- {
- zone_t *z = pgdat_list->node_zones;
-
- page = rmqueue(z, order);
- if (page)
- return page;
- }
/* No luck.. */
printk(KERN_INFO "__alloc_pages: %lu-order allocation failed.\n", order);
return NULL;
+
+out_success:
+ return page;
}

/*
@@ -588,7 +684,7 @@
sum = 0;
while (pgdat) {
for (zone = pgdat->node_zones; zone < pgdat->node_zones + MAX_NR_ZONES; zone++)
- sum += zone->free_pages;
+ sum += zone->free_pages - zone->reserved_pages;
pgdat = pgdat->node_next;
}
return sum;
@@ -605,7 +701,8 @@
sum = 0;
pgdat = pgdat_list;
while (pgdat) {
- sum += (pgdat->node_zones+zone_type)->free_pages;
+ zone_t *z = pgdat->node_zones+zone_type;
+ sum += z->free_pages - z->reserved_pages;
pgdat = pgdat->node_next;
}
return sum;
@@ -694,6 +791,7 @@

while (pgdat) {
pages += pgdat->node_zones[ZONE_HIGHMEM].free_pages;
+ pages -= pgdat->node_zones[ZONE_HIGHMEM].reserved_pages;
pgdat = pgdat->node_next;
}
return pages;
@@ -723,13 +821,37 @@
freepages.low,
freepages.high);

+ printk( "%8u %8u %8u %8u %8u %8u\n"
+ "%8u %8u %8u %8u %8u %8u\n"
+ "%8u %8u %8u %8u %8u %8u\n",
+ page_launder_calls,
+ page_launder_scans,
+ page_launder_scanned_pages,
+ page_launder_scanned_not_dirty,
+ page_launder_scanned_active,
+ page_launder_scanned_skipped,
+ page_launder_scanned_dirty,
+ page_launder_scanned_dirty_skip,
+ page_launder_scanned_dirty_nolaunder,
+ page_launder_scanned_dirty_swapcache,
+ page_launder_scanned_buffers,
+ page_launder_scanned_buffers_refiled,
+ page_launder_scanned_buffers_freed_buffer,
+ page_launder_scanned_buffers_active,
+ page_launder_scanned_buffers_cleaned,
+ page_launder_scanned_buffers_released,
+ page_launder_scanned_mapped_clean,
+ page_launder_scanned_still_active
+);
+
for (type = 0; type < MAX_NR_ZONES; type++) {
struct list_head *head, *curr;
zone_t *zone = pgdat->node_zones + type;
- unsigned long nr, total, flags;
+ unsigned long nr, total, flags, reserved;

- total = 0;
+ reserved = total = 0;
if (zone->size) {
+ printk("Zone %s: ", zone->name);
spin_lock_irqsave(&zone->lock, flags);
for (order = 0; order < MAX_ORDER; order++) {
head = &(zone->free_area + order)->free_list;
@@ -745,9 +867,10 @@
printk("%lu*%lukB ", nr,
(PAGE_SIZE>>10) << order);
}
+ reserved = zone->reserved_pages;
spin_unlock_irqrestore(&zone->lock, flags);
}
- printk("= %lukB)\n", total * (PAGE_SIZE>>10));
+ printk("= %lukB) Reserved: %lukB\n", total * (PAGE_SIZE>>10), reserved * (PAGE_SIZE>>10));
}

#ifdef SWAP_CACHE_INFO
@@ -901,8 +1024,11 @@
zone->lock = SPIN_LOCK_UNLOCKED;
zone->zone_pgdat = pgdat;
zone->free_pages = 0;
+ zone->reserved_pages = 0;
zone->inactive_clean_pages = 0;
zone->inactive_dirty_pages = 0;
+ zone->reserved_pages = 0;
+ INIT_LIST_HEAD(&zone->depleted_rsv_list);
memlist_init(&zone->inactive_clean_list);
if (!size)
continue;
@@ -914,7 +1040,7 @@
mask = zone_balance_min[j];
else if (mask > zone_balance_max[j])
mask = zone_balance_max[j];
- zone->pages_min = mask;
+ zone->pages_min = 0;
zone->pages_low = mask*2;
zone->pages_high = mask*3;
/*
@@ -928,7 +1054,7 @@
* for people who require it to catch load spikes in eg.
* gigabit ethernet routing...
*/
- freepages.min += mask;
+ freepages.min = 0;
freepages.low += mask*2;
freepages.high += mask*3;
zone->zone_mem_map = mem_map + offset;
@@ -955,12 +1081,16 @@
bitmap_size = size >> i;
bitmap_size = (bitmap_size + 7) >> 3;
bitmap_size = LONG_ALIGN(bitmap_size);
- bitmap_size *= 2;
+ bitmap_size *= 1;
zone->free_area[i].map =
(unsigned int *) alloc_bootmem_node(pgdat, bitmap_size);
}
}
build_zonelists(pgdat);
+
+ init_page_reservation(&irq_rsv, RSV_MULTISHOT, ZONE_NORMAL);
+ init_page_reservation(&swap_rsv, RSV_MULTISHOT, ZONE_NORMAL);
+ init_page_reservation(&atomic_rsv, RSV_MULTISHOT, ZONE_NORMAL);
}

void __init free_area_init(unsigned long *zones_size)
@@ -977,6 +1107,101 @@
for (j = 0; j < MAX_NR_ZONES; j++) printk("%d ", zone_balance_ratio[j]);
printk("\n");
return 1;
+}
+
+void init_page_reservation(struct page_reservation *rsv, int flags, int zone)
+{
+static int foo; if (foo++ < 5) printk("init_page_reservation(%p, %d, %d)\n", rsv, flags, zone);
+ INIT_LIST_HEAD(&rsv->list);
+ rsv->avail = 0;
+ rsv->used = 0;
+ rsv->flags = flags;
+
+ /* FIXME: This doesn't work properly on NUMA or multizoned setups.
+ */
+ rsv->zone = pgdat_list->node_zones + zone;
+}
+
+void destroy_page_reservation(struct page_reservation *rsv)
+{
+ unsigned long flags;
+ zone_t *zone = rsv->zone;
+static int foo; if (foo++ < 5) printk("destroy_page_reservation(%p)\n", rsv);
+
+ spin_lock_irqsave(&zone->lock, flags);
+ zone->reserved_pages -= rsv->avail;
+ list_del_init(&rsv->list); /* This relies on list_del_init being used */
+ spin_unlock_irqrestore(&zone->lock, flags);
+ memset(rsv, 0x57, sizeof(*rsv));
+}
+
+int reserve_pages(struct page_reservation *rsv, int gfp_mask, unsigned count)
+{
+ unsigned long flags, free_pages;
+ zone_t *zone = rsv->zone;
+ unsigned orig = count;
+ int tries = 5;
+static int foo; if (foo++ < 5) printk("reserve_pages(%p, %d, %u)\n", rsv, gfp_mask, count);
+
+ spin_lock_irqsave(&zone->lock, flags);
+ free_pages = zone->free_pages - zone->reserved_pages;
+ if (free_pages > count)
+ free_pages = count;
+ count -= free_pages;
+ zone->reserved_pages += free_pages;
+
+ rsv->used += count;
+ if (count)
+ zone->pages_min++;
+ list_del_init(&rsv->list);
+ if (rsv->used)
+ list_add(&rsv->list, zone->depleted_rsv_list.prev);
+
+ spin_unlock_irqrestore(&zone->lock, flags);
+
+ while (--tries && rsv->used) {
+ try_to_free_pages(gfp_mask);
+ if ((gfp_mask & __GFP_WAIT) && !(current->flags & PF_ATOMICALLOC)) {
+ __set_current_state(TASK_RUNNING);
+ current->policy |= SCHED_YIELD;
+ schedule();
+ }
+ }
+
+ if (count) {
+ spin_lock_irqsave(&zone->lock, flags);
+ zone->pages_min--;
+ spin_unlock_irqrestore(&zone->lock, flags);
+ }
+
+ if (!rsv->used)
+ return 0;
+
+ put_reserved_pages(rsv, orig);
+ return -ENOMEM;
+}
+
+void put_reserved_pages(struct page_reservation *rsv, unsigned count)
+{
+ unsigned long flags;
+ zone_t *zone = rsv->zone;
+static int foo; if (foo++ < 5) printk("put_reserved_pages(%p, %u)\n", rsv, count);
+ spin_lock_irqsave(&zone->lock, flags);
+
+ if (rsv->used <= count) {
+ count -= rsv->used;
+ rsv->used = 0;
+ } else {
+ rsv->used -= count;
+ count = 0;
+ }
+
+ if (count > rsv->avail)
+ BUG();
+
+ rsv->avail -= count;
+ zone->reserved_pages -= count;
+ spin_unlock_irqrestore(&zone->lock, flags);
}

__setup("memfrac=", setup_mem_frac);
diff --exclude=.* --exclude=*.[^ch]* -urN kernel-2.4.3-works/linux.orig/mm/vmscan.c linux-toolbox-current/mm/vmscan.c
--- kernel-2.4.3-works/linux.orig/mm/vmscan.c Thu May 10 16:07:27 2001
+++ linux-toolbox-current/mm/vmscan.c Mon May 14 13:30:26 2001
@@ -21,9 +21,32 @@
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/file.h>
+#include <linux/mm/reservation.h>

#include <asm/pgalloc.h>

+extern struct page_reservation swap_rsv;
+
+int page_launder_calls,
+ page_launder_scans,
+ page_launder_scanned_pages,
+ page_launder_scanned_not_dirty,
+ page_launder_scanned_active,
+ page_launder_scanned_skipped,
+ page_launder_scanned_dirty,
+ page_launder_scanned_dirty_skip,
+ page_launder_scanned_dirty_nolaunder,
+ page_launder_scanned_dirty_swapcache,
+ page_launder_scanned_buffers,
+ page_launder_scanned_buffers_refiled,
+ page_launder_scanned_buffers_freed_buffer,
+ page_launder_scanned_buffers_active,
+ page_launder_scanned_buffers_cleaned,
+ page_launder_scanned_buffers_released,
+ page_launder_scanned_mapped_clean,
+ page_launder_scanned_still_active
+;
+
/*
* The swap-out function returns 1 if it successfully
* scanned all the pages it was asked to (`count').
@@ -230,6 +253,14 @@
{
unsigned long address;
struct vm_area_struct* vma;
+ unsigned long min_rss = atomic_read(&mm->in_fault_count);
+
+ min_rss *= 64;
+ if (min_rss > 256)
+ min_rss = 256;
+
+ if (mm->rss <= min_rss)
+ return;

/*
* Go through process' page directory.
@@ -466,11 +497,18 @@
flushed_pages = 0;
freed_pages = 0;

+ spin_lock(&pagemap_lru_lock);
+ page_launder_calls++;
+ spin_unlock(&pagemap_lru_lock);
+
dirty_page_rescan:
spin_lock(&pagemap_lru_lock);
+ page_launder_scans++;
+
maxscan = nr_inactive_dirty_pages;
while ((page_lru = inactive_dirty_list.prev) != &inactive_dirty_list &&
maxscan-- > 0) {
+ page_launder_scanned_pages++;

page = list_entry(page_lru, struct page, lru);
zone = page->zone;
@@ -481,6 +519,7 @@
list_del(page_lru);
nr_inactive_dirty_pages--;
zone->inactive_dirty_pages--;
+ page_launder_scanned_not_dirty++;
continue;
}

@@ -490,6 +529,7 @@
page_ramdisk(page)) {
del_page_from_inactive_dirty_list(page);
add_page_to_active_list(page);
+ page_launder_scanned_active++;
continue;
}

@@ -505,7 +545,7 @@
if (launder_loop && !maxlaunder)
break;
if (launder_loop && zone->inactive_clean_pages +
- zone->free_pages > zone->pages_high)
+ zone->free_pages - zone->reserved_pages > zone->pages_high)
goto skip_page;

/*
@@ -514,6 +554,7 @@
*/
if (TryLockPage(page)) {
skip_page:
+ page_launder_scanned_skipped++;
list_del(page_lru);
list_add(page_lru, &inactive_dirty_list);
continue;
@@ -524,13 +565,19 @@
* last copy..
*/
if (PageDirty(page)) {
+ struct page_reservation *saved_rsv;
int (*writepage)(struct page *) = page->mapping->a_ops->writepage;

- if (!writepage || !can_get_io_locks)
+ page_launder_scanned_dirty++;
+
+ if (!writepage || !can_get_io_locks) {
+ page_launder_scanned_dirty_skip++;
goto page_active;
+ }

/* First time through? Move it to the back of the list */
if (!launder_loop) {
+ page_launder_scanned_dirty_nolaunder++;
list_del(page_lru);
list_add(page_lru, &inactive_dirty_list);
UnlockPage(page);
@@ -542,10 +589,16 @@
page_cache_get(page);
spin_unlock(&pagemap_lru_lock);

+ saved_rsv = current->page_reservations;
+ current->page_reservations = &swap_rsv;
writepage(page);
+ current->page_reservations = saved_rsv;
+
/* XXX: all ->writepage()s should use nr_async_pages */
if (!PageSwapCache(page))
flushed_pages++;
+ else
+ page_launder_scanned_dirty_swapcache++;
maxlaunder--;
page_cache_release(page);

@@ -565,6 +618,7 @@
*/
if (page->buffers) {
int wait, clearedbuf;
+ page_launder_scanned_buffers++;
/*
* Since we might be doing disk IO, we have to
* drop the spinlock and take an extra reference
@@ -594,21 +648,25 @@

/* The buffers were not freed. */
if (!clearedbuf) {
+ page_launder_scanned_buffers_refiled++;
add_page_to_inactive_dirty_list(page);
if (wait)
flushed_pages++;

/* The page was only in the buffer cache. */
} else if (!page->mapping) {
+ page_launder_scanned_buffers_freed_buffer++;
atomic_dec(&buffermem_pages);
freed_pages++;

/* The page has more users besides the cache and us. */
} else if (page_count(page) > 2) {
+ page_launder_scanned_buffers_active++;
add_page_to_active_list(page);

/* OK, we "created" a freeable page. */
} else /* page->mapping && page_count(page) == 2 */ {
+ page_launder_scanned_buffers_cleaned++;
add_page_to_inactive_clean_list(page);
freed_pages++;
}
@@ -618,10 +676,12 @@
* We can only do it here because we are accessing
* the page struct above.
*/
+ page_launder_scanned_buffers_released++;
UnlockPage(page);
page_cache_release(page);

} else if (page->mapping && !PageDirty(page)) {
+ page_launder_scanned_mapped_clean++;
/*
* If a page had an extra reference in
* deactivate_page(), we will find it here.
@@ -634,6 +694,7 @@
freed_pages++;

} else {
+ page_launder_scanned_still_active++;
page_active:
/*
* OK, we don't know what to do with the page.
@@ -660,6 +721,13 @@
*/
shortage = free_shortage();
if (can_get_io_locks && !launder_loop && shortage) {
+ if (gfp_mask & __GFP_WAIT) {
+ __set_current_state(TASK_RUNNING);
+ current->policy |= SCHED_YIELD;
+ schedule();
+ }
+
+ shortage = free_shortage();
launder_loop = 1;

/*
@@ -835,10 +903,11 @@
for(i = 0; i < MAX_NR_ZONES; i++) {
zone_t *zone = pgdat->node_zones+ i;
if (zone->size && (zone->inactive_clean_pages +
- zone->free_pages < zone->pages_min+1)) {
+ zone->free_pages - zone->reserved_pages < zone->pages_min+1)) {
/* + 1 to have overlap with alloc_pages() !! */
sum += zone->pages_min + 1;
sum -= zone->free_pages;
+ sum += zone->reserved_pages;
sum -= zone->inactive_clean_pages;
}
}
@@ -881,6 +950,7 @@
zone_shortage -= zone->inactive_dirty_pages;
zone_shortage -= zone->inactive_clean_pages;
zone_shortage -= zone->free_pages;
+ zone_shortage += zone->reserved_pages;
if (zone_shortage > 0)
shortage += zone_shortage;
}
@@ -1009,6 +1079,7 @@

int kswapd(void *unused)
{
+ static struct page_reservation kswapd_rsv;
struct task_struct *tsk = current;

tsk->session = 1;
@@ -1016,6 +1087,11 @@
strcpy(tsk->comm, "kswapd");
sigfillset(&tsk->blocked);
kswapd_task = tsk;
+
+ init_page_reservation(&kswapd_rsv, RSV_MULTISHOT, ZONE_NORMAL);
+ if (reserve_pages(&kswapd_rsv, GFP_KERNEL, 32))
+ panic("kswapd unable to reserve emergency pages!\n");
+ tsk->page_reservations = &kswapd_rsv;

/*
* Tell the memory management that we're a "memory allocator",
@@ -1086,6 +1162,8 @@
oom_kill();
}
}
+
+ destroy_page_reservation(&kswapd_rsv);
}

void wakeup_kswapd(void)
@@ -1102,6 +1180,10 @@
int try_to_free_pages(unsigned int gfp_mask)
{
int ret = 1;
+ struct page_reservation *rsv = current->page_reservations;
+
+ if (!rsv)
+ current->page_reservations = &swap_rsv;

if (gfp_mask & __GFP_WAIT) {
unsigned long caller_memalloc = current->flags & PF_MEMALLOC;
@@ -1111,6 +1193,8 @@
current->flags |= caller_memalloc;
}

+ current->page_reservations = rsv;
+
return ret;
}

@@ -1151,7 +1235,7 @@
if (!zone->size)
continue;

- while (zone->free_pages < zone->pages_low) {
+ while (zone->free_pages - zone->reserved_pages < zone->pages_low) {
struct page * page;
page = reclaim_page(zone);
if (!page)
-
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