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[PATCH] page migration: use allocator function for migrate_pages() 

Instead of passing a list of new pages, pass a function to allocate a new
page.  This allows the correct placement of MPOL_INTERLEAVE pages during page
migration.  It also further simplifies the callers of migrate pages.
migrate_pages() becomes similar to migrate_pages_to() so drop
migrate_pages_to().  The batching of new page allocations becomes unnecessary.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Jes Sorensen <jes@trained-monkey.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Christoph Lameter 2006-06-23 02:03:53 -07:00 committed by Linus Torvalds
parent aaa994b300
commit 95a402c384
3 changed files with 59 additions and 90 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
include/linux/migrate.h
View File

@ -3,14 +3,15 @@
#include <linux/mm.h>
typedef struct page *new_page_t(struct page *, unsigned long private);
#ifdef CONFIG_MIGRATION
extern int isolate_lru_page(struct page *p, struct list_head *pagelist);
extern int putback_lru_pages(struct list_head *l);
extern int migrate_page(struct address_space *,
struct page *, struct page *);
extern int migrate_pages(struct list_head *l, struct list_head *t);
extern int migrate_pages_to(struct list_head *pagelist,
struct vm_area_struct *vma, int dest);
extern int migrate_pages(struct list_head *l, new_page_t x, unsigned long);
extern int fail_migrate_page(struct address_space *,
struct page *, struct page *);
@ -21,8 +22,8 @@ extern int migrate_prep(void);
static inline int isolate_lru_page(struct page *p, struct list_head *list)
{ return -ENOSYS; }
static inline int putback_lru_pages(struct list_head *l) { return 0; }
static inline int migrate_pages(struct list_head *l, struct list_head *t)
{ return -ENOSYS; }
static inline int migrate_pages(struct list_head *l, new_page_t x,
unsigned long private) { return -ENOSYS; }
static inline int migrate_pages_to(struct list_head *pagelist,
struct vm_area_struct *vma, int dest) { return 0; }

23
mm/mempolicy.c
View File

@ -87,6 +87,7 @@
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <linux/migrate.h>
#include <linux/rmap.h>
#include <asm/tlbflush.h>
#include <asm/uaccess.h>
@ -587,6 +588,11 @@ static void migrate_page_add(struct page *page, struct list_head *pagelist,
isolate_lru_page(page, pagelist);
}
static struct page *new_node_page(struct page *page, unsigned long node)
{
return alloc_pages_node(node, GFP_HIGHUSER, 0);
}
/*
* Migrate pages from one node to a target node.
* Returns error or the number of pages not migrated.
@ -604,7 +610,8 @@ int migrate_to_node(struct mm_struct *mm, int source, int dest, int flags)
flags | MPOL_MF_DISCONTIG_OK, &pagelist);
if (!list_empty(&pagelist))
err = migrate_pages_to(&pagelist, NULL, dest);
err = migrate_pages(&pagelist, new_node_page, dest);
return err;
}
@ -691,6 +698,12 @@ int do_migrate_pages(struct mm_struct *mm,
}
static struct page *new_vma_page(struct page *page, unsigned long private)
{
struct vm_area_struct *vma = (struct vm_area_struct *)private;
return alloc_page_vma(GFP_HIGHUSER, vma, page_address_in_vma(page, vma));
}
#else
static void migrate_page_add(struct page *page, struct list_head *pagelist,
@ -703,6 +716,11 @@ int do_migrate_pages(struct mm_struct *mm,
{
return -ENOSYS;
}
static struct page *new_vma_page(struct page *page, unsigned long private)
{
return NULL;
}
#endif
long do_mbind(unsigned long start, unsigned long len,
@ -764,7 +782,8 @@ long do_mbind(unsigned long start, unsigned long len,
err = mbind_range(vma, start, end, new);
if (!list_empty(&pagelist))
nr_failed = migrate_pages_to(&pagelist, vma, -1);
nr_failed = migrate_pages(&pagelist, new_vma_page,
(unsigned long)vma);
if (!err && nr_failed && (flags & MPOL_MF_STRICT))
err = -EIO;

115
mm/migrate.c
View File

@ -28,9 +28,6 @@
#include "internal.h"
/* The maximum number of pages to take off the LRU for migration */
#define MIGRATE_CHUNK_SIZE 256
#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
/*
@ -587,18 +584,23 @@ static int move_to_new_page(struct page *newpage, struct page *page)
* Obtain the lock on page, remove all ptes and migrate the page
* to the newly allocated page in newpage.
*/
static int unmap_and_move(struct page *newpage, struct page *page, int force)
static int unmap_and_move(new_page_t get_new_page, unsigned long private,
struct page *page, int force)
{
int rc = 0;
struct page *newpage = get_new_page(page, private);
if (!newpage)
return -ENOMEM;
if (page_count(page) == 1)
/* page was freed from under us. So we are done. */
goto ret;
goto move_newpage;
rc = -EAGAIN;
if (TestSetPageLocked(page)) {
if (!force)
goto ret;
goto move_newpage;
lock_page(page);
}
@ -622,7 +624,7 @@ static int unmap_and_move(struct page *newpage, struct page *page, int force)
remove_migration_ptes(page, page);
unlock:
unlock_page(page);
ret:
if (rc != -EAGAIN) {
/*
* A page that has been migrated has all references
@ -632,29 +634,33 @@ ret:
*/
list_del(&page->lru);
move_to_lru(page);
list_del(&newpage->lru);
move_to_lru(newpage);
}
move_newpage:
/*
* Move the new page to the LRU. If migration was not successful
* then this will free the page.
*/
move_to_lru(newpage);
return rc;
}
/*
* migrate_pages
*
* Two lists are passed to this function. The first list
* contains the pages isolated from the LRU to be migrated.
* The second list contains new pages that the isolated pages
* can be moved to.
* The function takes one list of pages to migrate and a function
* that determines from the page to be migrated and the private data
* the target of the move and allocates the page.
*
* The function returns after 10 attempts or if no pages
* are movable anymore because to has become empty
* or no retryable pages exist anymore. All pages will be
* retruned to the LRU or freed.
*
* Return: Number of pages not migrated.
* Return: Number of pages not migrated or error code.
*/
int migrate_pages(struct list_head *from, struct list_head *to)
int migrate_pages(struct list_head *from,
new_page_t get_new_page, unsigned long private)
{
int retry = 1;
int nr_failed = 0;
@ -671,15 +677,14 @@ int migrate_pages(struct list_head *from, struct list_head *to)
retry = 0;
list_for_each_entry_safe(page, page2, from, lru) {
if (list_empty(to))
break;
cond_resched();
rc = unmap_and_move(lru_to_page(to), page, pass > 2);
rc = unmap_and_move(get_new_page, private,
page, pass > 2);
switch(rc) {
case -ENOMEM:
goto out;
case -EAGAIN:
retry++;
break;
@ -692,72 +697,16 @@ int migrate_pages(struct list_head *from, struct list_head *to)
}
}
}
rc = 0;
out:
if (!swapwrite)
current->flags &= ~PF_SWAPWRITE;
putback_lru_pages(from);
if (rc)
return rc;
return nr_failed + retry;
}
/*
* Migrate the list 'pagelist' of pages to a certain destination.
*
* Specify destination with either non-NULL vma or dest_node >= 0
* Return the number of pages not migrated or error code
*/
int migrate_pages_to(struct list_head *pagelist,
struct vm_area_struct *vma, int dest)
{
LIST_HEAD(newlist);
int err = 0;
unsigned long offset = 0;
int nr_pages;
int nr_failed = 0;
struct page *page;
struct list_head *p;
redo:
nr_pages = 0;
list_for_each(p, pagelist) {
if (vma) {
/*
* The address passed to alloc_page_vma is used to
* generate the proper interleave behavior. We fake
* the address here by an increasing offset in order
* to get the proper distribution of pages.
*
* No decision has been made as to which page
* a certain old page is moved to so we cannot
* specify the correct address.
*/
page = alloc_page_vma(GFP_HIGHUSER, vma,
offset + vma->vm_start);
offset += PAGE_SIZE;
}
else
page = alloc_pages_node(dest, GFP_HIGHUSER, 0);
if (!page) {
err = -ENOMEM;
goto out;
}
list_add_tail(&page->lru, &newlist);
nr_pages++;
if (nr_pages > MIGRATE_CHUNK_SIZE)
break;
}
err = migrate_pages(pagelist, &newlist);
if (err >= 0) {
nr_failed += err;
if (list_empty(&newlist) && !list_empty(pagelist))
goto redo;
}
out:
/* Calculate number of leftover pages */
list_for_each(p, pagelist)
nr_failed++;
return nr_failed;
}