From aaa994b300a172afafab47938804836b923e5ef7 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Fri, 23 Jun 2006 02:03:52 -0700 Subject: [PATCH] [PATCH] page migration: handle freeing of pages in migrate_pages() Do not leave pages on the lists passed to migrate_pages(). Seems that we will not need any postprocessing of pages. This will simplify the handling of pages by the callers of migrate_pages(). 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 --- include/linux/migrate.h | 7 +++--- mm/mempolicy.c | 8 +------ mm/migrate.c | 48 ++++++++++++++++++++--------------------- 3 files changed, 27 insertions(+), 36 deletions(-) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 287c47b5e5..83af25949f 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -8,8 +8,7 @@ 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, - struct list_head *moved, struct list_head *failed); +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 fail_migrate_page(struct address_space *, @@ -22,8 +21,8 @@ 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, - struct list_head *moved, struct list_head *failed) { return -ENOSYS; } +static inline int migrate_pages(struct list_head *l, struct list_head *t) + { 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 8778f58880..244f3f130e 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -603,11 +603,8 @@ int migrate_to_node(struct mm_struct *mm, int source, int dest, int flags) check_range(mm, mm->mmap->vm_start, TASK_SIZE, &nmask, flags | MPOL_MF_DISCONTIG_OK, &pagelist); - if (!list_empty(&pagelist)) { + if (!list_empty(&pagelist)) err = migrate_pages_to(&pagelist, NULL, dest); - if (!list_empty(&pagelist)) - putback_lru_pages(&pagelist); - } return err; } @@ -773,9 +770,6 @@ long do_mbind(unsigned long start, unsigned long len, err = -EIO; } - if (!list_empty(&pagelist)) - putback_lru_pages(&pagelist); - up_write(&mm->mmap_sem); mpol_free(new); return err; diff --git a/mm/migrate.c b/mm/migrate.c index 09038163bf..d3a1810a4c 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -624,6 +624,15 @@ unlock: unlock_page(page); ret: if (rc != -EAGAIN) { + /* + * A page that has been migrated has all references + * removed and will be freed. A page that has not been + * migrated will have kepts its references and be + * restored. + */ + list_del(&page->lru); + move_to_lru(page); + list_del(&newpage->lru); move_to_lru(newpage); } @@ -640,12 +649,12 @@ ret: * * The function returns after 10 attempts or if no pages * are movable anymore because to has become empty - * or no retryable pages exist anymore. + * or no retryable pages exist anymore. All pages will be + * retruned to the LRU or freed. * - * Return: Number of pages not migrated when "to" ran empty. + * Return: Number of pages not migrated. */ -int migrate_pages(struct list_head *from, struct list_head *to, - struct list_head *moved, struct list_head *failed) +int migrate_pages(struct list_head *from, struct list_head *to) { int retry = 1; int nr_failed = 0; @@ -675,11 +684,9 @@ int migrate_pages(struct list_head *from, struct list_head *to, retry++; break; case 0: - list_move(&page->lru, moved); break; default: /* Permanent failure */ - list_move(&page->lru, failed); nr_failed++; break; } @@ -689,6 +696,7 @@ int migrate_pages(struct list_head *from, struct list_head *to, if (!swapwrite) current->flags &= ~PF_SWAPWRITE; + putback_lru_pages(from); return nr_failed + retry; } @@ -702,11 +710,10 @@ int migrate_pages_to(struct list_head *pagelist, struct vm_area_struct *vma, int dest) { LIST_HEAD(newlist); - LIST_HEAD(moved); - LIST_HEAD(failed); int err = 0; unsigned long offset = 0; int nr_pages; + int nr_failed = 0; struct page *page; struct list_head *p; @@ -740,26 +747,17 @@ redo: if (nr_pages > MIGRATE_CHUNK_SIZE) break; } - err = migrate_pages(pagelist, &newlist, &moved, &failed); + err = migrate_pages(pagelist, &newlist); - putback_lru_pages(&moved); /* Call release pages instead ?? */ - - if (err >= 0 && list_empty(&newlist) && !list_empty(pagelist)) - goto redo; -out: - /* Return leftover allocated pages */ - while (!list_empty(&newlist)) { - page = list_entry(newlist.next, struct page, lru); - list_del(&page->lru); - __free_page(page); + if (err >= 0) { + nr_failed += err; + if (list_empty(&newlist) && !list_empty(pagelist)) + goto redo; } - list_splice(&failed, pagelist); - if (err < 0) - return err; +out: /* Calculate number of leftover pages */ - nr_pages = 0; list_for_each(p, pagelist) - nr_pages++; - return nr_pages; + nr_failed++; + return nr_failed; } -- 2.39.5