hugetlb: simplify migrate_huge_page()

Since we migrate only one hugepage don't use linked list for passing the
page around.  Directly pass page that need to be migrated as argument.
This also remove the usage page->lru in migrate path.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 855c337b20c35cb22ef0a3fa6213cfb82a3a90b0..ce7e6671968b791194df3c35d180443dbd615869 100644 (file)
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -15,7 +15,7 @@ extern int migrate_page(struct address_space *,
 extern int migrate_pages(struct list_head *l, new_page_t x,
                        unsigned long private, bool offlining,
                        enum migrate_mode mode);
-extern int migrate_huge_pages(struct list_head *l, new_page_t x,
+extern int migrate_huge_page(struct page *, new_page_t x,
                        unsigned long private, bool offlining,
                        enum migrate_mode mode);
 
@@ -36,7 +36,7 @@ static inline void putback_lru_pages(struct list_head *l) {}
 static inline int migrate_pages(struct list_head *l, new_page_t x,
                unsigned long private, bool offlining,
                enum migrate_mode mode) { return -ENOSYS; }
-static inline int migrate_huge_pages(struct list_head *l, new_page_t x,
+static inline int migrate_huge_page(struct page *page, new_page_t x,
                unsigned long private, bool offlining,
                enum migrate_mode mode) { return -ENOSYS; }
 

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index ab1e7145e2909c8e1a02359fb1e148118c42e1b2..4a45098fc4f555e5e2d2339c74d67c25b83e2e88 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1414,7 +1414,6 @@ static int soft_offline_huge_page(struct page *page, int flags)
        int ret;
        unsigned long pfn = page_to_pfn(page);
        struct page *hpage = compound_head(page);
-       LIST_HEAD(pagelist);
 
        ret = get_any_page(page, pfn, flags);
        if (ret < 0)
@@ -1429,19 +1428,11 @@ static int soft_offline_huge_page(struct page *page, int flags)
        }
 
        /* Keep page count to indicate a given hugepage is isolated. */
-
-       list_add(&hpage->lru, &pagelist);
-       ret = migrate_huge_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL, 0,
-                               true);
+       ret = migrate_huge_page(page, new_page, MPOL_MF_MOVE_ALL, 0, true);
+       put_page(page);
        if (ret) {
-               struct page *page1, *page2;
-               list_for_each_entry_safe(page1, page2, &pagelist, lru)
-                       put_page(page1);
-
                pr_info("soft offline: %#lx: migration failed %d, type %lx\n",
                        pfn, ret, page->flags);
-               if (ret > 0)
-                       ret = -EIO;
                return ret;
        }
 done:

diff --git a/mm/migrate.c b/mm/migrate.c
index 11072383ae12e5698498be5b3da5b8d991192535..69065ab09d0815065e4bbadb0a08969cc8374f91 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -929,15 +929,8 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
        if (anon_vma)
                put_anon_vma(anon_vma);
        unlock_page(hpage);
-
 out:
-       if (rc != -EAGAIN) {
-               list_del(&hpage->lru);
-               put_page(hpage);
-       }
-
        put_page(new_hpage);
-
        if (result) {
                if (rc)
                        *result = rc;
@@ -1013,48 +1006,32 @@ out:
        return nr_failed + retry;
 }
 
-int migrate_huge_pages(struct list_head *from,
-               new_page_t get_new_page, unsigned long private, bool offlining,
-               enum migrate_mode mode)
+int migrate_huge_page(struct page *hpage, new_page_t get_new_page,
+                     unsigned long private, bool offlining,
+                     enum migrate_mode mode)
 {
-       int retry = 1;
-       int nr_failed = 0;
-       int pass = 0;
-       struct page *page;
-       struct page *page2;
-       int rc;
-
-       for (pass = 0; pass < 10 && retry; pass++) {
-               retry = 0;
-
-               list_for_each_entry_safe(page, page2, from, lru) {
+       int pass, rc;
+
+       for (pass = 0; pass < 10; pass++) {
+               rc = unmap_and_move_huge_page(get_new_page,
+                                             private, hpage, pass > 2, offlining,
+                                             mode);
+               switch (rc) {
+               case -ENOMEM:
+                       goto out;
+               case -EAGAIN:
+                       /* try again */
                        cond_resched();
-
-                       rc = unmap_and_move_huge_page(get_new_page,
-                                       private, page, pass > 2, offlining,
-                                       mode);
-
-                       switch(rc) {
-                       case -ENOMEM:
-                               goto out;
-                       case -EAGAIN:
-                               retry++;
-                               break;
-                       case 0:
-                               break;
-                       default:
-                               /* Permanent failure */
-                               nr_failed++;
-                               break;
-                       }
+                       break;
+               case 0:
+                       goto out;
+               default:
+                       rc = -EIO;
+                       goto out;
                }
        }
-       rc = 0;
 out:
-       if (rc)
-               return rc;
-
-       return nr_failed + retry;
+       return rc;
 }
 
 #ifdef CONFIG_NUMA