Commit-ID: e9941dae870861da410835560b603d17c43dabee
Gitweb: http://git.kernel.org/tip/e9941dae870861da410835560b603d17c43dabee
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Sat, 3 Mar 2012 17:06:25 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 18 May 2012 08:16:21 +0200
mm/mpol: Lazy migrate a process/vma
Provide simple functions to lazy migrate a process (or part thereof).
These will be used to implement memory migration for NUMA process
migration.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
Cc: Paul Turner <pjt@xxxxxxxxxx>
Cc: Dan Smith <danms@xxxxxxxxxx>
Cc: Bharata B Rao <bharata.rao@xxxxxxxxx>
Cc: Lee Schermerhorn <Lee.Schermerhorn@xxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-pdhg3wh71m4eu8xerantpvln@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
include/linux/mempolicy.h | 3 ++
mm/mempolicy.c | 84 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 87 insertions(+), 0 deletions(-)
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 578fcd0..af2983b 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -262,6 +262,9 @@ extern int vma_migratable(struct vm_area_struct *);
extern int mpol_misplaced(struct page *, struct vm_area_struct *, unsigned long);
+extern void lazy_migrate_vma(struct vm_area_struct *vma, int node);
+extern void lazy_migrate_process(struct mm_struct *mm, int node);
+
#else
struct mempolicy {};
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 57fbc4c..df29149 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1193,6 +1193,90 @@ static long do_mbind(unsigned long start, unsigned long len,
return err;
}
+static nodemask_t mpol_node_mask(struct mempolicy *pol, int node)
+{
+ if (pol->mode == MPOL_PREFERRED) {
+ if (pol->flags & MPOL_F_LOCAL)
+ return nodemask_of_node(node);
+
+ return nodemask_of_node(pol->v.preferred_node);
+ }
+
+ return pol->v.nodes;
+}
+
+void lazy_migrate_vma(struct vm_area_struct *vma, int node)
+{
+ struct mempolicy *pol = NULL;
+ struct mempol_walk_data data;
+ struct mm_walk walk;
+ LIST_HEAD(pagelist);
+ nodemask_t nmask;
+
+ if (vma->vm_file)
+ return;
+
+ if (!vma_migratable(vma))
+ return;
+
+ /*
+ * Obtain a more-or-less correct nodemask to find which pages we need
+ * to unmap so that MoF can put them right again.
+ *
+ * Not quite correct for INTERLEAVE, that would need us doing
+ * offset_il_node() from check_pte_entry().
+ *
+ * Also not quite correct for task policies since we don't have a task,
+ * approximate by having @node function as local / task-home-node.
+ */
+
+ if (vma->vm_ops && vma->vm_ops->get_policy)
+ pol = vma->vm_ops->get_policy(vma, vma->vm_start);
+ else if (vma->vm_policy)
+ pol = vma->vm_policy;
+
+ if (pol) {
+ nmask = mpol_node_mask(pol, node);
+ mpol_cond_put(pol);
+
+ /*
+ * If there's an explicit policy that doesn't support MoF, skip
+ * this vma, there's nothing we can do about that.
+ */
+ if (!(pol->flags & MPOL_F_MOF))
+ return;
+ } else
+ nmask = nodemask_of_node(node);
+
+ data = (struct mempol_walk_data){
+ .nodes = &nmask,
+ .flags = MPOL_MF_MOVE | MPOL_MF_INVERT, /* move all pages not in set */
+ .private = &pagelist,
+ .vma = vma,
+ };
+
+ walk = (struct mm_walk){
+ .pte_entry = check_pte_entry,
+ .mm = vma->vm_mm,
+ .private = &data,
+ };
+
+ if (!walk_page_range(vma->vm_start, vma->vm_end, &walk))
+ migrate_pages_unmap_only(&pagelist);
+
+ putback_lru_pages(&pagelist);
+}
+
+void lazy_migrate_process(struct mm_struct *mm, int node)
+{
+ struct vm_area_struct *vma;
+
+ down_read(&mm->mmap_sem);
+ for (vma = mm->mmap; vma; vma = vma->vm_next)
+ lazy_migrate_vma(vma, node);
+ up_read(&mm->mmap_sem);
+}
+
/*
* User space interface with variable sized bitmaps for nodelists.
*/
--
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