[patch] NEW: arca-vm-21, swapout via shrink_mmap using PG_dirty

Andrea Arcangeli
1999-01-16T00:39:26Z

I did not understood what PG_dirty means until this afternoon I thought
"why not to move the rw_swap_page to shrink_mmap" and left swap_out() only
to allocate the in-order-swap-entry and its swap cache page? So I brute
moved the rw_swap_cache with obviously tons of races and worked for a
bit well ;).

Then I seen the PG_dirty comment of Linus in vmscan.c, and if I have
understood well it, I had to use PG_dirty to realize what I was going to
do.

So I hacked heavily all the afternoon and the evening and now seems to
work fine ;)). Really the free_user_and_cache() algorithm that I am using
in this patch is "new", never seen how it works with the usual swapout
code in swap_out() so I can't make raw comparison.

What I can say is that the global performances seems improved a lot (also
the OOM handling seems improved, try and you'll see). But the raw swapout
performances are been reduced (from 51 sec of arca-vm-19 to 61 sec).
Seems very good here though.

The patch merge also other my stuff like my update_shared_mapping() that
is safe right now (at last as vmtruncate ;). It fix also the for_each_mm
issue. I can cut-out the garbage if somebody needs...

Ah and the patch removed also the map_nr field since x86 should perform
equally well (and the removal saves some bits of memory). This is been an
idea from Max.

Don't use the patch without first doing a backup though since mm
corruption could happens since I could have done mistaken.

I would be interested if somebody could make comparison with arca-vm-19 or
pre[57] for example... but don't waste time doing many benchmarks if it
seems a lose under every side.

Probably in low memory (<=8m) this my new arca-vm-21 needs a:

echo 6 1 4 32 128 512 >/proc/sys/vm/pager

Thanks.

Here arca-vm-21 against 2.2.0-pre7:

Index: linux/mm/filemap.c
diff -u linux/mm/filemap.c:1.1.1.9 linux/mm/filemap.c:1.1.1.1.2.52
--- linux/mm/filemap.c:1.1.1.9 Thu Jan 7 12:21:35 1999
+++ linux/mm/filemap.c Sat Jan 16 00:17:39 1999
@@ -5,6 +5,11 @@
*/

/*
+ * update_shared_mappings(), Copyright (C) 1998 Andrea Arcangeli
+ * PG_dirty shrink_mmap swapout, Copyright (C) 1999 Andrea Arcangeli
+ */
+
+/*
* This file handles the generic file mmap semantics used by
* most "normal" filesystems (but you don't /have/ to use this:
* the NFS filesystem used to do this differently, for example)
@@ -121,14 +126,11 @@
int shrink_mmap(int priority, int gfp_mask)
{
static unsigned long clock = 0;
- unsigned long limit = num_physpages;
struct page * page;
- int count;
-
- count = (limit << 1) >> priority;
+ unsigned long count = (num_physpages << 1) >> priority;

page = mem_map + clock;
- do {
+ while (count-- != 0) {
int referenced;

/* This works even in the presence of PageSkip because
@@ -144,10 +146,9 @@
if (PageSkip(page)) {
/* next_hash is overloaded for PageSkip */
page = page->next_hash;
- clock = page->map_nr;
+ clock = page - mem_map;
}

- count--;
referenced = test_and_clear_bit(PG_referenced, &page->flags);

if (PageLocked(page))
@@ -160,21 +161,6 @@
if (atomic_read(&page->count) != 1)
continue;

- /*
- * Is it a page swap page? If so, we want to
- * drop it if it is no longer used, even if it
- * were to be marked referenced..
- */
- if (PageSwapCache(page)) {
- if (referenced && swap_count(page->offset) != 1)
- continue;
- delete_from_swap_cache(page);
- return 1;
- }
-
- if (referenced)
- continue;
-
/* Is it a buffer page? */
if (page->buffers) {
if (buffer_under_min())
@@ -184,6 +170,26 @@
return 1;
}

+ if (referenced)
+ continue;
+
+ if (PageSwapCache(page)) {
+ unsigned long entry = page->offset;
+ if (PageTestandClearDirty(page) &&
+ swap_count(entry) > 1)
+ {
+ if (!(gfp_mask & __GFP_IO))
+ continue;
+ entry = page->offset;
+ set_bit(PG_locked, &page->flags);
+ atomic_inc(&page->count);
+ rw_swap_page(WRITE, entry, page, 0);
+ atomic_dec(&page->count);
+ }
+ delete_from_swap_cache(page);
+ return 1;
+ }
+
/* is it a page-cache page? */
if (page->inode) {
if (pgcache_under_min())
@@ -191,8 +197,7 @@
remove_inode_page(page);
return 1;
}
-
- } while (count > 0);
+ }
return 0;
}

@@ -1165,6 +1170,74 @@
return mk_pte(page,vma->vm_page_prot);
}

+static void update_one_shared_mapping(struct vm_area_struct *shared,
+ unsigned long address, pte_t orig_pte)
+{
+ pgd_t *pgd;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ pgd = pgd_offset(shared->vm_mm, address);
+ if (pgd_none(*pgd))
+ goto out;
+ if (pgd_bad(*pgd)) {
+ printk(KERN_ERR "update_shared_mappings: bad pgd (%08lx)\n",
+ pgd_val(*pgd));
+ pgd_clear(pgd);
+ goto out;
+ }
+
+ pmd = pmd_offset(pgd, address);
+ if (pmd_none(*pmd))
+ goto out;
+ if (pmd_bad(*pmd))
+ {
+ printk(KERN_ERR "update_shared_mappings: bad pmd (%08lx)\n",
+ pmd_val(*pmd));
+ pmd_clear(pmd);
+ goto out;
+ }
+
+ pte = pte_offset(pmd, address);
+
+ if (pte_val(pte_mkclean(pte_mkyoung(*pte))) !=
+ pte_val(pte_mkclean(pte_mkyoung(orig_pte))))
+ goto out;
+
+ flush_page_to_ram(page(pte));
+ flush_cache_page(shared, address);
+ set_pte(pte, pte_mkclean(*pte));
+ flush_tlb_page(shared, address);
+
+ out:
+}
+
+static void update_shared_mappings(struct vm_area_struct *this,
+ unsigned long address,
+ pte_t orig_pte)
+{
+ if (this->vm_flags & VM_SHARED)
+ {
+ struct file * filp = this->vm_file;
+ if (filp)
+ {
+ struct inode * inode = filp->f_dentry->d_inode;
+ struct semaphore * s = &inode->i_sem;
+ struct vm_area_struct * shared;
+
+ down(s);
+ for (shared = inode->i_mmap; shared;
+ shared = shared->vm_next_share)
+ {
+ if (shared->vm_mm == this->vm_mm)
+ continue;
+ update_one_shared_mapping(shared, address,
+ orig_pte);
+ }
+ up(s);
+ }
+ }
+}

static inline int filemap_sync_pte(pte_t * ptep, struct vm_area_struct *vma,
unsigned long address, unsigned int flags)
@@ -1184,6 +1257,7 @@
flush_tlb_page(vma, address);
page = pte_page(pte);
atomic_inc(&mem_map[MAP_NR(page)].count);
+ update_shared_mappings(vma, address, pte);
} else {
if (pte_none(pte))
return 0;
Index: linux/mm/mmap.c
diff -u linux/mm/mmap.c:1.1.1.2 linux/mm/mmap.c:1.1.1.1.2.12
--- linux/mm/mmap.c:1.1.1.2 Fri Nov 27 11:19:10 1998
+++ linux/mm/mmap.c Wed Jan 13 21:23:38 1999
@@ -66,7 +66,7 @@
free += page_cache_size;
free += nr_free_pages;
free += nr_swap_pages;
- free -= (page_cache.min_percent + buffer_mem.min_percent + 2)*num_physpages/100;
+ free -= (pager_daemon.cache_min_percent + pager_daemon.buffer_min_percent + 2)*num_physpages/100;
return free > pages;
}

@@ -76,11 +76,16 @@
struct file * file = vma->vm_file;

if (file) {
+ struct semaphore * sem = &file->f_dentry->d_inode->i_sem;
+ struct file * file = vma->vm_file;
+
+ down(sem);
if (vma->vm_flags & VM_DENYWRITE)
file->f_dentry->d_inode->i_writecount++;
if(vma->vm_next_share)
vma->vm_next_share->vm_pprev_share = vma->vm_pprev_share;
*vma->vm_pprev_share = vma->vm_next_share;
+ up(sem);
}
}

@@ -514,9 +519,6 @@
free = free->vm_next;
freed = 1;

- mm->map_count--;
- remove_shared_vm_struct(mpnt);
-
st = addr < mpnt->vm_start ? mpnt->vm_start : addr;
end = addr+len;
end = end > mpnt->vm_end ? mpnt->vm_end : end;
@@ -525,6 +527,9 @@
if (mpnt->vm_ops && mpnt->vm_ops->unmap)
mpnt->vm_ops->unmap(mpnt, st, size);

+ mm->map_count--;
+ remove_shared_vm_struct(mpnt);
+
flush_cache_range(mm, st, end);
zap_page_range(mm, st, size);
flush_tlb_range(mm, st, end);
@@ -616,14 +621,18 @@
file = vmp->vm_file;
if (file) {
struct inode * inode = file->f_dentry->d_inode;
+ struct semaphore * sem = &inode->i_sem;
+
if (vmp->vm_flags & VM_DENYWRITE)
inode->i_writecount--;

+ down(sem);
/* insert vmp into inode's share list */
if((vmp->vm_next_share = inode->i_mmap) != NULL)
inode->i_mmap->vm_pprev_share = &vmp->vm_next_share;
inode->i_mmap = vmp;
vmp->vm_pprev_share = &inode->i_mmap;
+ up(sem);
}
}

Index: linux/mm/page_alloc.c
diff -u linux/mm/page_alloc.c:1.1.1.9 linux/mm/page_alloc.c:1.1.1.1.2.32
--- linux/mm/page_alloc.c:1.1.1.9 Thu Jan 14 12:32:57 1999
+++ linux/mm/page_alloc.c Fri Jan 15 21:48:00 1999
@@ -124,8 +124,7 @@
if (!PageReserved(page) && atomic_dec_and_test(&page->count)) {
if (PageSwapCache(page))
panic ("Freeing swap cache page");
- page->flags &= ~(1 << PG_referenced);
- free_pages_ok(page->map_nr, 0);
+ free_pages_ok(page - mem_map, 0);
return;
}
}
@@ -141,7 +140,6 @@
if (atomic_dec_and_test(&map->count)) {
if (PageSwapCache(map))
panic ("Freeing swap cache pages");
- map->flags &= ~(1 << PG_referenced);
free_pages_ok(map_nr, order);
return;
}
@@ -163,7 +161,7 @@
if (!dma || CAN_DMA(ret)) { \
unsigned long map_nr; \
(prev->next = ret->next)->prev = prev; \
- map_nr = ret->map_nr; \
+ map_nr = ret - mem_map; \
MARK_USED(map_nr, new_order, area); \
nr_free_pages -= 1 << order; \
EXPAND(ret, map_nr, order, new_order, area); \
@@ -212,19 +210,18 @@
* further thought.
*/
if (!(current->flags & PF_MEMALLOC)) {
- static int trashing = 0;
int freed;

if (nr_free_pages > freepages.min) {
- if (!trashing)
+ if (!current->trashing)
goto ok_to_allocate;
if (nr_free_pages > freepages.low) {
- trashing = 0;
+ current->trashing = 0;
goto ok_to_allocate;
}
}

- trashing = 1;
+ current->trashing = 1;
current->flags |= PF_MEMALLOC;
freed = try_to_free_pages(gfp_mask);
current->flags &= ~PF_MEMALLOC;
@@ -322,7 +319,6 @@
--p;
atomic_set(&p->count, 0);
p->flags = (1 << PG_DMA) | (1 << PG_reserved);
- p->map_nr = p - mem_map;
} while (p > mem_map);

for (i = 0 ; i < NR_MEM_LISTS ; i++) {
@@ -361,7 +357,7 @@
if (offset >= swapdev->max)
break;
/* Don't block on I/O for read-ahead */
- if (atomic_read(&nr_async_pages) >= pager_daemon.swap_cluster)
+ if (atomic_read(&nr_async_pages) >= pager_daemon.max_async_pages)
break;
/* Don't read in bad or busy pages */
if (!swapdev->swap_map[offset])
Index: linux/mm/page_io.c
diff -u linux/mm/page_io.c:1.1.1.4 linux/mm/page_io.c:1.1.1.1.2.7
--- linux/mm/page_io.c:1.1.1.4 Tue Dec 29 01:39:20 1998
+++ linux/mm/page_io.c Fri Jan 15 21:48:00 1999
@@ -58,7 +58,7 @@
}

/* Don't allow too many pending pages in flight.. */
- if (atomic_read(&nr_async_pages) > pager_daemon.swap_cluster)
+ if (atomic_read(&nr_async_pages) > pager_daemon.max_async_pages)
wait = 1;

p = &swap_info[type];
@@ -233,10 +233,8 @@
/* A simple wrapper so the base function doesn't need to enforce
* that all swap pages go through the swap cache!
*/
-void rw_swap_page(int rw, unsigned long entry, char *buf, int wait)
+void rw_swap_page(int rw, unsigned long entry, struct page *page, int wait)
{
- struct page *page = mem_map + MAP_NR(buf);
-
if (page->inode && page->inode != &swapper_inode)
panic ("Tried to swap a non-swapper page");

@@ -281,7 +279,7 @@
page->inode = &swapper_inode;
page->offset = entry;
atomic_inc(&page->count); /* Protect from shrink_mmap() */
- rw_swap_page(rw, entry, buffer, 1);
+ rw_swap_page(rw, entry, page, 1);
atomic_dec(&page->count);
page->inode = 0;
clear_bit(PG_swap_cache, &page->flags);
Index: linux/mm/swap.c
diff -u linux/mm/swap.c:1.1.1.6 linux/mm/swap.c:1.1.1.1.2.18
--- linux/mm/swap.c:1.1.1.6 Mon Jan 11 22:24:24 1999
+++ linux/mm/swap.c Sat Jan 16 00:00:55 1999
@@ -40,28 +40,19 @@
};

/* How many pages do we try to swap or page in/out together? */
-int page_cluster = 4; /* Default value modified in swap_setup() */
+int page_cluster = 5; /* Default readahead 32 pages every time */

/* We track the number of pages currently being asynchronously swapped
out, so that we don't try to swap TOO many pages out at once */
atomic_t nr_async_pages = ATOMIC_INIT(0);

-buffer_mem_t buffer_mem = {
- 2, /* minimum percent buffer */
- 10, /* borrow percent buffer */
- 60 /* maximum percent buffer */
-};
-
-buffer_mem_t page_cache = {
- 2, /* minimum percent page cache */
- 15, /* borrow percent page cache */
- 75 /* maximum */
-};
-
pager_daemon_t pager_daemon = {
- 512, /* base number for calculating the number of tries */
- SWAP_CLUSTER_MAX, /* minimum number of tries */
- SWAP_CLUSTER_MAX, /* do swap I/O in clusters of this size */
+ 10, /* starting priority of try_to_free_pages() */
+ 1, /* minimum percent buffer */
+ 5, /* minimum percent page cache */
+ 32, /* number of tries we do on every try_to_free_pages() */
+ 128, /* do swap I/O in clusters of this size */
+ 512 /* max number of async swapped-out pages on the fly */
};

/*
@@ -75,6 +66,4 @@
page_cluster = 2;
else if (num_physpages < ((32 * 1024 * 1024) >> PAGE_SHIFT))
page_cluster = 3;
- else
- page_cluster = 4;
}
Index: linux/mm/swap_state.c
diff -u linux/mm/swap_state.c:1.1.1.6 linux/mm/swap_state.c:1.1.1.1.2.13
--- linux/mm/swap_state.c:1.1.1.6 Thu Jan 14 12:32:57 1999
+++ linux/mm/swap_state.c Fri Jan 15 23:23:54 1999
@@ -213,6 +213,7 @@
"entry %08lx)\n",
page_address(page), atomic_read(&page->count), entry);
#endif
+ PageClearDirty(page);
remove_from_swap_cache (page);
swap_free (entry);
}
@@ -320,7 +321,7 @@
goto out_free_page;

set_bit(PG_locked, &new_page->flags);
- rw_swap_page(READ, entry, (char *) new_page_addr, wait);
+ rw_swap_page(READ, entry, new_page, wait);
#ifdef DEBUG_SWAP
printk("DebugVM: read_swap_cache_async created "
"entry %08lx at %p\n",
Index: linux/mm/swapfile.c
diff -u linux/mm/swapfile.c:1.1.1.3 linux/mm/swapfile.c:1.1.1.1.2.6
--- linux/mm/swapfile.c:1.1.1.3 Mon Jan 11 22:24:24 1999
+++ linux/mm/swapfile.c Wed Jan 13 00:00:04 1999
@@ -23,7 +23,6 @@

struct swap_info_struct swap_info[MAX_SWAPFILES];

-#define SWAPFILE_CLUSTER 256

static inline int scan_swap_map(struct swap_info_struct *si)
{
@@ -31,7 +30,7 @@
/*
* We try to cluster swap pages by allocating them
* sequentially in swap. Once we've allocated
- * SWAPFILE_CLUSTER pages this way, however, we resort to
+ * SWAP_CLUSTER pages this way, however, we resort to
* first-free allocation, starting a new cluster. This
* prevents us from scattering swap pages all over the entire
* swap partition, so that we reduce overall disk seek times
@@ -47,7 +46,7 @@
goto got_page;
}
}
- si->cluster_nr = SWAPFILE_CLUSTER;
+ si->cluster_nr = SWAP_CLUSTER;
for (offset = si->lowest_bit; offset <= si->highest_bit ; offset++) {
if (si->swap_map[offset])
continue;
Index: linux/mm/vmalloc.c
diff -u linux/mm/vmalloc.c:1.1.1.2 linux/mm/vmalloc.c:1.1.1.1.2.3
--- linux/mm/vmalloc.c:1.1.1.2 Fri Nov 27 11:19:11 1998
+++ linux/mm/vmalloc.c Thu Dec 31 18:55:11 1998
@@ -10,6 +10,7 @@
#include <asm/uaccess.h>

static struct vm_struct * vmlist = NULL;
+static spinlock_t vmlist_spinlock;

static inline void free_area_pte(pmd_t * pmd, unsigned long address, unsigned long size)
{
@@ -158,17 +159,21 @@
if (!area)
return NULL;
addr = VMALLOC_START;
+ spin_lock(&vmlist_spinlock);
for (p = &vmlist; (tmp = *p) ; p = &tmp->next) {
if (size + addr < (unsigned long) tmp->addr)
break;
- if (addr > VMALLOC_END-size)
+ if (addr > VMALLOC_END-size) {
+ spin_unlock(&vmlist_spinlock);
return NULL;
+ }
addr = tmp->size + (unsigned long) tmp->addr;
}
area->addr = (void *)addr;
area->size = size + PAGE_SIZE;
area->next = *p;
*p = area;
+ spin_unlock(&vmlist_spinlock);
return area;
}

@@ -182,14 +187,18 @@
printk("Trying to vfree() bad address (%p)\n", addr);
return;
}
+ spin_lock(&vmlist_spinlock);
for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {
if (tmp->addr == addr) {
*p = tmp->next;
- vmfree_area_pages(VMALLOC_VMADDR(tmp->addr), tmp->size);
+ spin_unlock(&vmlist_spinlock);
+ vmfree_area_pages(VMALLOC_VMADDR(tmp->addr),
+ tmp->size - PAGE_SIZE);
kfree(tmp);
return;
}
}
+ spin_unlock(&vmlist_spinlock);
printk("Trying to vfree() nonexistent vm area (%p)\n", addr);
}

@@ -222,6 +231,7 @@
if ((unsigned long) addr + count < count)
count = -(unsigned long) addr;

+ spin_lock(&vmlist_spinlock);
for (tmp = vmlist; tmp; tmp = tmp->next) {
vaddr = (char *) tmp->addr;
if (addr >= vaddr + tmp->size - PAGE_SIZE)
@@ -245,5 +255,6 @@
} while (--n > 0);
}
finished:
+ spin_unlock(&vmlist_spinlock);
return buf - buf_start;
}
Index: linux/mm/vmscan.c
diff -u linux/mm/vmscan.c:1.1.1.12 linux/mm/vmscan.c:1.1.1.1.2.98
--- linux/mm/vmscan.c:1.1.1.12 Mon Jan 11 22:24:24 1999
+++ linux/mm/vmscan.c Sat Jan 16 00:06:41 1999
@@ -10,6 +10,12 @@
* Version: $Id: vmscan.c,v 1.5 1998/02/23 22:14:28 sct Exp $
*/

+/*
+ * free_user_and_cache() and always async swapout original idea.
+ * PG_dirty shrink_mmap swapout
+ * Copyright (C) 1999 Andrea Arcangeli
+ */
+
#include <linux/slab.h>
#include <linux/kernel_stat.h>
#include <linux/swap.h>
@@ -20,6 +26,8 @@

#include <asm/pgtable.h>

+int swapout_interval = HZ;
+
/*
* The swap-out functions return 1 if they successfully
* threw something out, and we got a free page. It returns
@@ -53,12 +61,7 @@
return 0;

if (pte_young(pte)) {
- /*
- * Transfer the "accessed" bit from the page
- * tables to the global page map.
- */
set_pte(page_table, pte_mkold(pte));
- set_bit(PG_referenced, &page_map->flags);
return 0;
}

@@ -66,9 +69,6 @@
* Is the page already in the swap cache? If so, then
* we can just drop our reference to it without doing
* any IO - it's already up-to-date on disk.
- *
- * Return 0, as we didn't actually free any real
- * memory, and we should just continue our scan.
*/
if (PageSwapCache(page_map)) {
entry = page_map->offset;
@@ -77,8 +77,9 @@
drop_pte:
vma->vm_mm->rss--;
flush_tlb_page(vma, address);
+ entry = atomic_read(&page_map->count);
__free_page(page_map);
- return 0;
+ return entry <= 2;
}

/*
@@ -86,11 +87,6 @@
* by just paging it in again, and we can just drop
* it..
*
- * However, this won't actually free any real
- * memory, as the page will just be in the page cache
- * somewhere, and as such we should just continue
- * our scan.
- *
* Basically, this just makes it possible for us to do
* some real work in the future in "shrink_mmap()".
*/
@@ -127,7 +123,10 @@
* That would get rid of a lot of problems.
*/
if (vma->vm_ops && vma->vm_ops->swapout) {
- pid_t pid = tsk->pid;
+ pid_t pid;
+ if (!(gfp_mask & __GFP_IO))
+ return 0;
+ pid = tsk->pid;
vma->vm_mm->rss--;
if (vma->vm_ops->swapout(vma, address - vma->vm_start + vma->vm_offset, page_table))
kill_proc(pid, SIGBUS, 1);
@@ -151,14 +150,9 @@
set_pte(page_table, __pte(entry));
flush_tlb_page(vma, address);
swap_duplicate(entry); /* One for the process, one for the swap cache */
- add_to_swap_cache(page_map, entry);
- /* We checked we were unlocked way up above, and we
- have been careful not to stall until here */
- set_bit(PG_locked, &page_map->flags);
-
- /* OK, do a physical asynchronous write to swap. */
- rw_swap_page(WRITE, entry, (char *) page, 0);
-
+ add_to_swap_cache(page_map, entry);
+ if (PageTestandSetDirty(page_map))
+ printk(KERN_ERR "VM: page was just marked dirty!\n");
__free_page(page_map);
return 1;
}
@@ -199,7 +193,7 @@

do {
int result;
- tsk->swap_address = address + PAGE_SIZE;
+ tsk->mm->swap_address = address + PAGE_SIZE;
result = try_to_swap_out(tsk, vma, address, pte, gfp_mask);
if (result)
return result;
@@ -271,7 +265,7 @@
/*
* Go through process' page directory.
*/
- address = p->swap_address;
+ address = p->mm->swap_address;

/*
* Find the proper vm-area
@@ -293,8 +287,8 @@
}

/* We didn't find anything for the process */
- p->swap_cnt = 0;
- p->swap_address = 0;
+ p->mm->swap_cnt = 0;
+ p->mm->swap_address = 0;
return 0;
}

@@ -303,10 +297,11 @@
* N.B. This function returns only 0 or 1. Return values != 1 from
* the lower level routines result in continued processing.
*/
-static int swap_out(unsigned int priority, int gfp_mask)
+static int grow_freeable(unsigned int priority, int gfp_mask)
{
struct task_struct * p, * pbest;
- int counter, assign, max_cnt;
+ int counter, assign;
+ unsigned long max_cnt;

/*
* We make one or two passes through the task list, indexed by
@@ -325,8 +320,6 @@
counter = nr_tasks / (priority+1);
if (counter < 1)
counter = 1;
- if (counter > nr_tasks)
- counter = nr_tasks;

for (; counter >= 0; counter--) {
assign = 0;
@@ -338,13 +331,13 @@
for (; p != &init_task; p = p->next_task) {
if (!p->swappable)
continue;
- if (p->mm->rss <= 0)
+ if (p->mm->rss == 0)
continue;
/* Refresh swap_cnt? */
if (assign)
- p->swap_cnt = p->mm->rss;
- if (p->swap_cnt > max_cnt) {
- max_cnt = p->swap_cnt;
+ p->mm->swap_cnt = p->mm->rss;
+ if (p->mm->swap_cnt > max_cnt) {
+ max_cnt = p->mm->swap_cnt;
pbest = p;
}
}
@@ -376,7 +369,7 @@
char *revision="$Revision: 1.5 $", *s, *e;

swap_setup();
-
+
if ((s = strchr(revision, ':')) &&
(e = strchr(s, '$')))
s++, i = e - s;
@@ -406,12 +399,6 @@
strcpy(current->comm, "kswapd");

/*
- * Hey, if somebody wants to kill us, be our guest.
- * Don't come running to mama if things don't work.
- */
- siginitsetinv(&current->blocked, sigmask(SIGKILL));
-
- /*
* Tell the memory management that we're a "memory allocator",
* and that if we need more memory we should get access to it
* regardless (see "__get_free_pages()"). "kswapd" should
@@ -426,11 +413,10 @@
current->flags |= PF_MEMALLOC;

while (1) {
- if (signal_pending(current))
- break;
- current->state = TASK_INTERRUPTIBLE;
run_task_queue(&tq_disk);
- schedule_timeout(HZ);
+ current->state = TASK_INTERRUPTIBLE;
+ flush_signals(current);
+ schedule_timeout(swapout_interval);

/*
* kswapd isn't even meant to keep up with anything,
@@ -438,13 +424,37 @@
* point is to make sure that the system doesn't stay
* forever in a really bad memory squeeze.
*/
- if (nr_free_pages < freepages.high)
+ if (nr_free_pages < freepages.min)
try_to_free_pages(GFP_KSWAPD);
}

return 0;
}

+static int free_user_and_cache(int priority, int gfp_mask)
+{
+ int freed, grown = 0;
+ static int need_freeable = 0;
+
+ freed = shrink_mmap(priority, gfp_mask);
+
+ if (need_freeable)
+ {
+ grown = grow_freeable(priority, gfp_mask);
+ if (freed)
+ need_freeable = 0;
+ } else {
+ freed = shrink_mmap(priority, gfp_mask);
+ if (!freed)
+ {
+ grown = grow_freeable(priority, gfp_mask);
+ need_freeable = 1;
+ }
+ }
+
+ return freed || grown;
+}
+
/*
* We need to make the locks finer granularity, but right
* now we need this so that we can do page allocations
@@ -457,34 +467,35 @@
int try_to_free_pages(unsigned int gfp_mask)
{
int priority;
- int count = SWAP_CLUSTER_MAX;
+ static int state = 0;
+ int count = pager_daemon.tries;

lock_kernel();

/* Always trim SLAB caches when memory gets low. */
kmem_cache_reap(gfp_mask);

- priority = 6;
- do {
- while (shrink_mmap(priority, gfp_mask)) {
- if (!--count)
- goto done;
- }
-
- /* Try to get rid of some shared memory pages.. */
- while (shm_swap(priority, gfp_mask)) {
- if (!--count)
- goto done;
- }
-
- /* Then, try to page stuff out.. */
- while (swap_out(priority, gfp_mask)) {
- if (!--count)
- goto done;
- }
+ priority = pager_daemon.priority;
+ switch (state)
+ {
+ do {
+ case 0:
+ while (free_user_and_cache(priority, gfp_mask)) {
+ if (!--count)
+ goto done;
+ }
+ state = 1;
+ case 1:
+ /* Try to get rid of some shared memory pages.. */
+ while (shm_swap(priority, gfp_mask)) {
+ if (!--count)
+ goto done;
+ }
+ state = 0;

- shrink_dcache_memory(priority, gfp_mask);
- } while (--priority >= 0);
+ shrink_dcache_memory(priority, gfp_mask);
+ } while (--priority >= 0);
+ }
done:
unlock_kernel();

Index: linux/kernel/fork.c
diff -u linux/kernel/fork.c:1.1.1.6 linux/kernel/fork.c:1.1.1.1.2.10
--- linux/kernel/fork.c:1.1.1.6 Mon Jan 11 22:24:21 1999
+++ linux/kernel/fork.c Mon Jan 11 22:56:09 1999
@@ -209,16 +209,19 @@
tmp->vm_next = NULL;
file = tmp->vm_file;
if (file) {
+ struct semaphore * s = &file->f_dentry->d_inode->i_sem;
file->f_count++;
if (tmp->vm_flags & VM_DENYWRITE)
file->f_dentry->d_inode->i_writecount--;
-
+
+ down(s);
/* insert tmp into the share list, just after mpnt */
if((tmp->vm_next_share = mpnt->vm_next_share) != NULL)
mpnt->vm_next_share->vm_pprev_share =
&tmp->vm_next_share;
mpnt->vm_next_share = tmp;
tmp->vm_pprev_share = &mpnt->vm_next_share;
+ up(s);
}

/* Copy the pages, but defer checking for errors */
@@ -511,6 +514,7 @@

p->did_exec = 0;
p->swappable = 0;
+ p->trashing = 0;
p->state = TASK_UNINTERRUPTIBLE;

copy_flags(clone_flags, p);
Index: linux/kernel/sysctl.c
diff -u linux/kernel/sysctl.c:1.1.1.6 linux/kernel/sysctl.c:1.1.1.1.2.12
--- linux/kernel/sysctl.c:1.1.1.6 Mon Jan 11 22:24:22 1999
+++ linux/kernel/sysctl.c Wed Jan 13 21:23:38 1999
@@ -32,7 +32,7 @@

/* External variables not in a header file. */
extern int panic_timeout;
-extern int console_loglevel, C_A_D;
+extern int console_loglevel, C_A_D, swapout_interval;
extern int bdf_prm[], bdflush_min[], bdflush_max[];
extern char binfmt_java_interpreter[], binfmt_java_appletviewer[];
extern int sysctl_overcommit_memory;
@@ -216,6 +216,8 @@
};

static ctl_table vm_table[] = {
+ {VM_SWAPOUT, "swapout_interval",
+ &swapout_interval, sizeof(int), 0644, NULL, &proc_dointvec},
{VM_FREEPG, "freepages",
&freepages, sizeof(freepages_t), 0644, NULL, &proc_dointvec},
{VM_BDFLUSH, "bdflush", &bdf_prm, 9*sizeof(int), 0600, NULL,
@@ -223,11 +225,7 @@
&bdflush_min, &bdflush_max},
{VM_OVERCOMMIT_MEMORY, "overcommit_memory", &sysctl_overcommit_memory,
sizeof(sysctl_overcommit_memory), 0644, NULL, &proc_dointvec},
- {VM_BUFFERMEM, "buffermem",
- &buffer_mem, sizeof(buffer_mem_t), 0644, NULL, &proc_dointvec},
- {VM_PAGECACHE, "pagecache",
- &page_cache, sizeof(buffer_mem_t), 0644, NULL, &proc_dointvec},
- {VM_PAGERDAEMON, "kswapd",
+ {VM_PAGERDAEMON, "pager",
&pager_daemon, sizeof(pager_daemon_t), 0644, NULL, &proc_dointvec},
{VM_PGT_CACHE, "pagetable_cache",
&pgt_cache_water, 2*sizeof(int), 0600, NULL, &proc_dointvec},
Index: linux/include/linux/mm.h
diff -u linux/include/linux/mm.h:1.1.1.6 linux/include/linux/mm.h:1.1.1.1.2.23
--- linux/include/linux/mm.h:1.1.1.6 Mon Jan 11 22:23:57 1999
+++ linux/include/linux/mm.h Fri Jan 15 23:23:53 1999
@@ -118,12 +118,10 @@
unsigned long offset;
struct page *next_hash;
atomic_t count;
- unsigned int unused;
unsigned long flags; /* atomic flags, some possibly updated asynchronously */
struct wait_queue *wait;
struct page **pprev_hash;
struct buffer_head * buffers;
- unsigned long map_nr; /* page->map_nr == page - mem_map */
} mem_map_t;

/* Page flag bit values */
@@ -165,6 +163,7 @@

#define PageClearSlab(page) (clear_bit(PG_Slab, &(page)->flags))
#define PageClearSwapCache(page)(clear_bit(PG_swap_cache, &(page)->flags))
+#define PageClearDirty(page) (clear_bit(PG_dirty, &(page)->flags))

#define PageTestandClearDirty(page) \
(test_and_clear_bit(PG_dirty, &(page)->flags))
@@ -302,8 +301,7 @@

/* filemap.c */
extern void remove_inode_page(struct page *);
-extern unsigned long page_unuse(struct page *);
-extern int shrink_mmap(int, int);
+extern int FASTCALL(shrink_mmap(int, int));
extern void truncate_inode_pages(struct inode *, unsigned long);
extern unsigned long get_cached_page(struct inode *, unsigned long, int);
extern void put_cached_page(unsigned long);
@@ -387,9 +385,9 @@
}

#define buffer_under_min() ((buffermem >> PAGE_SHIFT) * 100 < \
- buffer_mem.min_percent * num_physpages)
-#define pgcache_under_min() (page_cache_size * 100 < \
- page_cache.min_percent * num_physpages)
+ pager_daemon.buffer_min_percent * num_physpages)
+#define pgcache_under_min() ((page_cache_size-swapper_inode.i_nrpages) * 100 < \
+ pager_daemon.cache_min_percent * num_physpages)

#endif /* __KERNEL__ */

Index: linux/include/linux/pagemap.h
diff -u linux/include/linux/pagemap.h:1.1.1.1 linux/include/linux/pagemap.h:1.1.1.1.2.3
--- linux/include/linux/pagemap.h:1.1.1.1 Fri Nov 20 00:01:16 1998
+++ linux/include/linux/pagemap.h Fri Jan 15 21:47:58 1999
@@ -14,7 +14,7 @@

static inline unsigned long page_address(struct page * page)
{
- return PAGE_OFFSET + PAGE_SIZE * page->map_nr;
+ return PAGE_OFFSET + ((page - mem_map) << PAGE_SHIFT);
}

#define PAGE_HASH_BITS 11
Index: linux/include/linux/sched.h
diff -u linux/include/linux/sched.h:1.1.1.6 linux/include/linux/sched.h:1.1.1.1.2.13
--- linux/include/linux/sched.h:1.1.1.6 Mon Jan 11 22:24:03 1999
+++ linux/include/linux/sched.h Thu Jan 14 12:42:58 1999
@@ -169,6 +174,7 @@
unsigned long rss, total_vm, locked_vm;
unsigned long def_flags;
unsigned long cpu_vm_mask;
+ unsigned long swap_cnt, swap_address;
/*
* This is an architecture-specific pointer: the portable
* part of Linux does not know about any segments.
@@ -177,15 +183,17 @@
};

#define INIT_MM { \
- &init_mmap, NULL, swapper_pg_dir, \
+ &init_mmap, NULL, swapper_pg_dir, \
ATOMIC_INIT(1), 1, \
MUTEX, \
0, \
0, 0, 0, 0, \
- 0, 0, 0, \
+ 0, 0, 0, \
0, 0, 0, 0, \
0, 0, 0, \
- 0, 0, NULL }
+ 0, 0, \
+ 0, 0, \
+ NULL }

struct signal_struct {
atomic_t count;
@@ -270,8 +278,7 @@
/* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
unsigned long min_flt, maj_flt, nswap, cmin_flt, cmaj_flt, cnswap;
int swappable:1;
- unsigned long swap_address;
- unsigned long swap_cnt; /* number of pages to swap on next pass */
+ int trashing:1;
/* process credentials */
uid_t uid,euid,suid,fsuid;
gid_t gid,egid,sgid,fsgid;
@@ -355,7 +362,7 @@
/* utime */ {0,0,0,0},0, \
/* per CPU times */ {0, }, {0, }, \
/* flt */ 0,0,0,0,0,0, \
-/* swp */ 0,0,0, \
+/* swp */ 0,0, \
/* process credentials */ \
/* uid etc */ 0,0,0,0,0,0,0,0, \
/* suppl grps*/ 0, {0,}, \
Index: linux/include/linux/swap.h
diff -u linux/include/linux/swap.h:1.1.1.6 linux/include/linux/swap.h:1.1.1.1.2.19
--- linux/include/linux/swap.h:1.1.1.6 Mon Jan 11 22:24:05 1999
+++ linux/include/linux/swap.h Fri Jan 15 21:47:58 1999
@@ -33,7 +33,7 @@
#define SWP_USED 1
#define SWP_WRITEOK 3

-#define SWAP_CLUSTER_MAX 32
+#define SWAP_CLUSTER (pager_daemon.swap_cluster)

#define SWAP_MAP_MAX 0x7fff
#define SWAP_MAP_BAD 0x8000
@@ -76,7 +76,7 @@
extern int try_to_free_pages(unsigned int gfp_mask);

/* linux/mm/page_io.c */
-extern void rw_swap_page(int, unsigned long, char *, int);
+extern void rw_swap_page(int, unsigned long, struct page *, int);
extern void rw_swap_page_nocache(int, unsigned long, char *);
extern void rw_swap_page_nolock(int, unsigned long, char *, int);
extern void swap_after_unlock_page (unsigned long entry);
@@ -134,13 +134,6 @@
extern unsigned long swap_cache_find_total;
extern unsigned long swap_cache_find_success;
#endif
-
-extern inline unsigned long in_swap_cache(struct page *page)
-{
- if (PageSwapCache(page))
- return page->offset;
- return 0;
-}

/*
* Work out if there are any other processes sharing this page, ignoring
Index: linux/include/linux/swapctl.h
diff -u linux/include/linux/swapctl.h:1.1.1.4 linux/include/linux/swapctl.h:1.1.1.1.2.9
--- linux/include/linux/swapctl.h:1.1.1.4 Mon Jan 11 22:24:05 1999
+++ linux/include/linux/swapctl.h Fri Jan 15 23:23:53 1999
@@ -4,32 +4,23 @@
#include <asm/page.h>
#include <linux/fs.h>

-typedef struct buffer_mem_v1
+typedef struct freepages_s
{
- unsigned int min_percent;
- unsigned int borrow_percent;
- unsigned int max_percent;
-} buffer_mem_v1;
-typedef buffer_mem_v1 buffer_mem_t;
-extern buffer_mem_t buffer_mem;
-extern buffer_mem_t page_cache;
-
-typedef struct freepages_v1
-{
unsigned int min;
unsigned int low;
unsigned int high;
-} freepages_v1;
-typedef freepages_v1 freepages_t;
+} freepages_t;
extern freepages_t freepages;

-typedef struct pager_daemon_v1
+typedef struct pager_daemon_s
{
- unsigned int tries_base;
- unsigned int tries_min;
+ unsigned int priority;
+ unsigned int buffer_min_percent;
+ unsigned int cache_min_percent;
+ unsigned int tries;
unsigned int swap_cluster;
-} pager_daemon_v1;
-typedef pager_daemon_v1 pager_daemon_t;
+ unsigned int max_async_pages;
+} pager_daemon_t;
extern pager_daemon_t pager_daemon;

#endif /* _LINUX_SWAPCTL_H */