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Date: Wed, 3 Apr 2013 16:52:23 -0700
From: John Stultz <john.stultz@...aro.org>
To: linux-kernel@...r.kernel.org
Cc: John Stultz <john.stultz@...aro.org>, linux-mm@...ck.org,
Michael Kerrisk <mtk.manpages@...il.com>,
Arun Sharma <asharma@...com>, Mel Gorman <mel@....ul.ie>,
Hugh Dickins <hughd@...gle.com>, Dave Hansen <dave@...1.net>,
Rik van Riel <riel@...hat.com>, Neil Brown <neilb@...e.de>,
Mike Hommey <mh@...ndium.org>, Taras Glek <tglek@...illa.com>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
Jason Evans <je@...com>, sanjay@...gle.com,
Paul Turner <pjt@...gle.com>,
Johannes Weiner <hannes@...xchg.org>,
Michel Lespinasse <walken@...gle.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Minchan Kim <minchan@...nel.org>
Subject: [RFC PATCH 4/4] vrange: Enable purging of file backed volatile ranges
Rework the victim range selection to also support
file backed volatile ranges.
Cc: linux-mm@...ck.org
Cc: Michael Kerrisk <mtk.manpages@...il.com>
Cc: Arun Sharma <asharma@...com>
Cc: Mel Gorman <mel@....ul.ie>
Cc: Hugh Dickins <hughd@...gle.com>
Cc: Dave Hansen <dave@...1.net>
Cc: Rik van Riel <riel@...hat.com>
Cc: Neil Brown <neilb@...e.de>
Cc: Mike Hommey <mh@...ndium.org>
Cc: Taras Glek <tglek@...illa.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Cc: Jason Evans <je@...com>
Cc: sanjay@...gle.com
Cc: Paul Turner <pjt@...gle.com>
Cc: Johannes Weiner <hannes@...xchg.org>
Cc: Michel Lespinasse <walken@...gle.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Minchan Kim <minchan@...nel.org>
Signed-off-by: John Stultz <john.stultz@...aro.org>
---
include/linux/vrange.h | 8 ++++
mm/vrange.c | 118 +++++++++++++++++++++++++++++++++---------------
2 files changed, 89 insertions(+), 37 deletions(-)
diff --git a/include/linux/vrange.h b/include/linux/vrange.h
index 91960eb..bada2bd 100644
--- a/include/linux/vrange.h
+++ b/include/linux/vrange.h
@@ -47,6 +47,14 @@ static inline struct mm_struct *vrange_get_owner_mm(struct vrange *vrange)
return container_of(vrange->owner, struct mm_struct, vroot);
}
+static inline
+struct address_space *vrange_get_owner_mapping(struct vrange *vrange)
+{
+ if (vrange_type(vrange) != VRANGE_FILE)
+ return NULL;
+ return container_of(vrange->owner, struct address_space, vroot);
+}
+
void vrange_init(void);
extern void mm_exit_vrange(struct mm_struct *mm);
diff --git a/mm/vrange.c b/mm/vrange.c
index 671909c..b652513 100644
--- a/mm/vrange.c
+++ b/mm/vrange.c
@@ -690,8 +690,9 @@ static unsigned int discard_vma_pages(struct zone *zone, struct mm_struct *mm,
return ret;
}
-unsigned int discard_vrange(struct zone *zone, struct vrange *vrange,
- int nr_to_discard)
+static unsigned int discard_anon_vrange(struct zone *zone,
+ struct vrange *vrange,
+ int nr_to_discard)
{
struct mm_struct *mm;
unsigned long start = vrange->node.start;
@@ -732,52 +733,91 @@ out:
return nr_discarded;
}
+static unsigned int discard_file_vrange(struct zone *zone,
+ struct vrange *vrange,
+ int nr_to_discard)
+{
+ struct address_space *mapping;
+ unsigned long start = vrange->node.start;
+ unsigned long end = vrange->node.last;
+ unsigned long count = ((end-start) >> PAGE_CACHE_SHIFT);
+
+ mapping = vrange_get_owner_mapping(vrange);
+
+ truncate_inode_pages_range(mapping, start, end);
+ vrange->purged = true;
+
+ return count;
+}
+
+unsigned int discard_vrange(struct zone *zone, struct vrange *vrange,
+ int nr_to_discard)
+{
+ if (vrange_type(vrange) == VRANGE_ANON)
+ return discard_anon_vrange(zone, vrange, nr_to_discard);
+ return discard_file_vrange(zone, vrange, nr_to_discard);
+}
+
+
+/* Take a vrange refcount and depending on the type
+ * the vrange->owner's mm refcount or inode refcount
+ */
+static int hold_victim_vrange(struct vrange *vrange)
+{
+ if (vrange_type(vrange) == VRANGE_ANON) {
+ struct mm_struct *mm = vrange_get_owner_mm(vrange);
+
+
+ if (atomic_read(&mm->mm_users) == 0)
+ return -1;
+
+
+ if (!atomic_inc_not_zero(&vrange->refcount))
+ return -1;
+ /*
+ * we need to access mmap_sem further routine so
+ * need to get a refcount of mm.
+ * NOTE: We guarantee mm_count isn't zero in here because
+ * if we found vrange from LRU list, it means we are
+ * before exit_vrange or remove_vrange.
+ */
+ atomic_inc(&mm->mm_count);
+ } else {
+ struct address_space *mapping;
+ mapping = vrange_get_owner_mapping(vrange);
+
+ if (!atomic_inc_not_zero(&vrange->refcount))
+ return -1;
+ __iget(mapping->host);
+ }
+
+ return 0;
+}
+
+
+
/*
- * Get next victim vrange from LRU and hold a vrange refcount
- * and vrange->mm's refcount.
+ * Get next victim vrange from LRU and hold needed refcounts.
*/
static struct vrange *get_victim_vrange(void)
{
- struct mm_struct *mm;
struct vrange *vrange = NULL;
struct list_head *cur, *tmp;
spin_lock(&lru_lock);
list_for_each_prev_safe(cur, tmp, &lru_vrange) {
vrange = list_entry(cur, struct vrange, lru);
- mm = vrange_get_owner_mm(vrange);
-
- if (!mm) {
- vrange = NULL;
- continue;
- }
- /* the process is exiting so pass it */
- if (atomic_read(&mm->mm_users) == 0) {
+ if (hold_victim_vrange(vrange)) {
list_del_init(&vrange->lru);
vrange = NULL;
continue;
}
- /* vrange is freeing so continue to loop */
- if (!atomic_inc_not_zero(&vrange->refcount)) {
- list_del_init(&vrange->lru);
- vrange = NULL;
- continue;
- }
-
- /*
- * we need to access mmap_sem further routine so
- * need to get a refcount of mm.
- * NOTE: We guarantee mm_count isn't zero in here because
- * if we found vrange from LRU list, it means we are
- * before mm_exit_vrange or remove_vrange.
- */
- atomic_inc(&mm->mm_count);
-
/* Isolate vrange */
list_del_init(&vrange->lru);
break;
+
}
spin_unlock(&lru_lock);
@@ -786,11 +826,18 @@ static struct vrange *get_victim_vrange(void)
static void put_victim_range(struct vrange *vrange)
{
- struct mm_struct *mm = vrange_get_owner_mm(vrange);
-
put_vrange(vrange);
- if (mm)
+
+ if (vrange_type(vrange) == VRANGE_ANON) {
+ struct mm_struct *mm = vrange_get_owner_mm(vrange);
+
mmdrop(mm);
+ } else {
+ struct address_space *mapping;
+
+ mapping = vrange_get_owner_mapping(vrange);
+ iput(mapping->host);
+ }
}
unsigned int discard_vrange_pages(struct zone *zone, int nr_to_discard)
@@ -799,11 +846,8 @@ unsigned int discard_vrange_pages(struct zone *zone, int nr_to_discard)
unsigned int nr_discarded = 0;
start_vrange = vrange = get_victim_vrange();
- if (start_vrange) {
- struct mm_struct *mm = vrange_get_owner_mm(vrange);
- atomic_inc(&start_vrange->refcount);
- atomic_inc(&mm->mm_count);
- }
+ if (start_vrange)
+ hold_victim_vrange(start_vrange);
while (vrange) {
nr_discarded += discard_vrange(zone, vrange, nr_to_discard);
--
1.7.10.4
--
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