From: Christoph Lameter Date: Fri, 23 Jun 2006 09:03:53 +0000 (-0700) Subject: [PATCH] page migration: use allocator function for migrate_pages() X-Git-Tag: v2.6.18-rc1~1081^2~156 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=95a402c3847cc16f4ba03013cd01404fa0f14c2e;p=linux-2.6 [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 Cc: Hugh Dickins Cc: Jes Sorensen Cc: KAMEZAWA Hiroyuki Cc: Lee Schermerhorn Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 83af25949f..5b95d6568d 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -3,14 +3,15 @@ #include +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; } diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 244f3f130e..f432642e9e 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -87,6 +87,7 @@ #include #include #include +#include #include #include @@ -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; diff --git a/mm/migrate.c b/mm/migrate.c index d3a1810a4c..251a8d1582 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -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); - 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: + if (rc) + return rc; - /* Calculate number of leftover pages */ - list_for_each(p, pagelist) - nr_failed++; - return nr_failed; + return nr_failed + retry; } +