From 3140a2273009c01c27d316f35ab76a37e105fdd8 Mon Sep 17 00:00:00 2001 From: Brice Goglin Date: Tue, 6 Jan 2009 14:38:57 -0800 Subject: [PATCH] mm: rework do_pages_move() to work on page_sized chunks Rework do_pages_move() to work by page-sized chunks of struct page_to_node that are passed to do_move_page_to_node_array(). We now only have to allocate a single page instead a possibly very large vmalloc area to store all page_to_node entries. As a result, new_page_node() will now have a very small lookup, hidding much of the overall sys_move_pages() overhead. Signed-off-by: Brice Goglin Signed-off-by: Nathalie Furmento Acked-by: Christoph Lameter Cc: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/migrate.c | 79 +++++++++++++++++++++++++++++----------------------- 1 file changed, 44 insertions(+), 35 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 21631ab8c08b..0a75716cb736 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -919,41 +919,43 @@ static int do_pages_move(struct mm_struct *mm, struct task_struct *task, const int __user *nodes, int __user *status, int flags) { - struct page_to_node *pm = NULL; + struct page_to_node *pm; nodemask_t task_nodes; - int err = 0; - int i; + unsigned long chunk_nr_pages; + unsigned long chunk_start; + int err; task_nodes = cpuset_mems_allowed(task); - /* Limit nr_pages so that the multiplication may not overflow */ - if (nr_pages >= ULONG_MAX / sizeof(struct page_to_node) - 1) { - err = -E2BIG; - goto out; - } - - pm = vmalloc((nr_pages + 1) * sizeof(struct page_to_node)); - if (!pm) { - err = -ENOMEM; + err = -ENOMEM; + pm = (struct page_to_node *)__get_free_page(GFP_KERNEL); + if (!pm) goto out; - } - /* - * Get parameters from user space and initialize the pm - * array. Return various errors if the user did something wrong. + * Store a chunk of page_to_node array in a page, + * but keep the last one as a marker */ - for (i = 0; i < nr_pages; i++) { - const void __user *p; + chunk_nr_pages = (PAGE_SIZE / sizeof(struct page_to_node)) - 1; - err = -EFAULT; - if (get_user(p, pages + i)) - goto out_pm; + for (chunk_start = 0; + chunk_start < nr_pages; + chunk_start += chunk_nr_pages) { + int j; - pm[i].addr = (unsigned long)p; - if (nodes) { + if (chunk_start + chunk_nr_pages > nr_pages) + chunk_nr_pages = nr_pages - chunk_start; + + /* fill the chunk pm with addrs and nodes from user-space */ + for (j = 0; j < chunk_nr_pages; j++) { + const void __user *p; int node; - if (get_user(node, nodes + i)) + err = -EFAULT; + if (get_user(p, pages + j + chunk_start)) + goto out_pm; + pm[j].addr = (unsigned long) p; + + if (get_user(node, nodes + j + chunk_start)) goto out_pm; err = -ENODEV; @@ -964,22 +966,29 @@ static int do_pages_move(struct mm_struct *mm, struct task_struct *task, if (!node_isset(node, task_nodes)) goto out_pm; - pm[i].node = node; - } else - pm[i].node = 0; /* anything to not match MAX_NUMNODES */ - } - /* End marker */ - pm[nr_pages].node = MAX_NUMNODES; + pm[j].node = node; + } + + /* End marker for this chunk */ + pm[chunk_nr_pages].node = MAX_NUMNODES; + + /* Migrate this chunk */ + err = do_move_page_to_node_array(mm, pm, + flags & MPOL_MF_MOVE_ALL); + if (err < 0) + goto out_pm; - err = do_move_page_to_node_array(mm, pm, flags & MPOL_MF_MOVE_ALL); - if (err >= 0) /* Return status information */ - for (i = 0; i < nr_pages; i++) - if (put_user(pm[i].status, status + i)) + for (j = 0; j < chunk_nr_pages; j++) + if (put_user(pm[j].status, status + j + chunk_start)) { err = -EFAULT; + goto out_pm; + } + } + err = 0; out_pm: - vfree(pm); + free_page((unsigned long)pm); out: return err; } -- 2.20.1