From 7b2259b3e53f128c10a9fded0965e69d4a949847 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Sun, 25 Jun 2006 05:46:48 -0700 Subject: [PATCH] page migration: Support a vma migration function Hooks for calling vma specific migration functions With this patch a vma may define a vma->vm_ops->migrate function. That function may perform page migration on its own (some vmas may not contain page structs and therefore cannot be handled by regular page migration. Pages in a vma may require special preparatory treatment before migration is possible etc) . Only mmap_sem is held when the migration function is called. The migrate() function gets passed two sets of nodemasks describing the source and the target of the migration. The flags parameter either contains MPOL_MF_MOVE which means that only pages used exclusively by the specified mm should be moved or MPOL_MF_MOVE_ALL which means that pages shared with other processes should also be moved. The migration function returns 0 on success or an error condition. An error condition will prevent regular page migration from occurring. On its own this patch cannot be included since there are no users for this functionality. But it seems that the uncached allocator will need this functionality at some point. Signed-off-by: Christoph Lameter Cc: Hugh Dickins Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/migrate.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 1c2a71aa05cd..0576c0535988 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -976,3 +976,23 @@ out2: } #endif +/* + * Call migration functions in the vma_ops that may prepare + * memory in a vm for migration. migration functions may perform + * the migration for vmas that do not have an underlying page struct. + */ +int migrate_vmas(struct mm_struct *mm, const nodemask_t *to, + const nodemask_t *from, unsigned long flags) +{ + struct vm_area_struct *vma; + int err = 0; + + for(vma = mm->mmap; vma->vm_next && !err; vma = vma->vm_next) { + if (vma->vm_ops && vma->vm_ops->migrate) { + err = vma->vm_ops->migrate(vma, to, from, flags); + if (err) + break; + } + } + return err; +} -- cgit v1.2.3-59-g8ed1b