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authorGuoqing Jiang <guoqing.jiang@cloud.ionos.com>2019-12-23 12:49:00 +0300
committerSong Liu <songliubraving@fb.com>2020-01-13 22:44:10 +0300
commit69b00b5bb23552d43e8bbed73ef6624604bb94a2 (patch)
tree6192d67dc8dab6d064c370666d990f22081c189b /drivers/md/md.c
parent4d26d32fe4dafd29e168addb7c11949a36e7e5f8 (diff)
downloadlinux-69b00b5bb23552d43e8bbed73ef6624604bb94a2.tar.xz
md: introduce a new struct for IO serialization
Obviously, IO serialization could cause the degradation of performance a lot. In order to reduce the degradation, so a rb interval tree is added in raid1 to speed up the check of collision. So, a rb root is needed in md_rdev, then abstract all the serialize related members to a new struct (serial_in_rdev), embed it into md_rdev. Of course, we need to free the struct if it is not needed anymore, so rdev/rdevs_uninit_serial are added accordingly. And they should be called when destroty memory pool or can't alloc memory. And we need to consider to call mddev_destroy_serial_pool in case serialize_policy/write-behind is disabled, bitmap is destroyed or in __md_stop_writes. Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Song Liu <songliubraving@fb.com>
Diffstat (limited to 'drivers/md/md.c')
-rw-r--r--drivers/md/md.c80
1 files changed, 62 insertions, 18 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 788559f42d43..9c4e61c988ac 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -125,25 +125,59 @@ static inline int speed_max(struct mddev *mddev)
mddev->sync_speed_max : sysctl_speed_limit_max;
}
+static void rdev_uninit_serial(struct md_rdev *rdev)
+{
+ if (!test_and_clear_bit(CollisionCheck, &rdev->flags))
+ return;
+
+ kfree(rdev->serial);
+ rdev->serial = NULL;
+}
+
+static void rdevs_uninit_serial(struct mddev *mddev)
+{
+ struct md_rdev *rdev;
+
+ rdev_for_each(rdev, mddev)
+ rdev_uninit_serial(rdev);
+}
+
static int rdev_init_serial(struct md_rdev *rdev)
{
- spin_lock_init(&rdev->serial_list_lock);
- INIT_LIST_HEAD(&rdev->serial_list);
- init_waitqueue_head(&rdev->serial_io_wait);
+ struct serial_in_rdev *serial = NULL;
+
+ if (test_bit(CollisionCheck, &rdev->flags))
+ return 0;
+
+ serial = kmalloc(sizeof(struct serial_in_rdev), GFP_KERNEL);
+ if (!serial)
+ return -ENOMEM;
+
+ spin_lock_init(&serial->serial_lock);
+ serial->serial_rb = RB_ROOT_CACHED;
+ init_waitqueue_head(&serial->serial_io_wait);
+ rdev->serial = serial;
set_bit(CollisionCheck, &rdev->flags);
- return 1;
+ return 0;
}
-static void rdevs_init_serial(struct mddev *mddev)
+static int rdevs_init_serial(struct mddev *mddev)
{
struct md_rdev *rdev;
+ int ret = 0;
rdev_for_each(rdev, mddev) {
- if (test_bit(CollisionCheck, &rdev->flags))
- continue;
- rdev_init_serial(rdev);
+ ret = rdev_init_serial(rdev);
+ if (ret)
+ break;
}
+
+ /* Free all resources if pool is not existed */
+ if (ret && !mddev->serial_info_pool)
+ rdevs_uninit_serial(mddev);
+
+ return ret;
}
/*
@@ -166,6 +200,8 @@ static int rdev_need_serial(struct md_rdev *rdev)
void mddev_create_serial_pool(struct mddev *mddev, struct md_rdev *rdev,
bool is_suspend)
{
+ int ret = 0;
+
if (rdev && !rdev_need_serial(rdev) &&
!test_bit(CollisionCheck, &rdev->flags))
return;
@@ -174,9 +210,11 @@ void mddev_create_serial_pool(struct mddev *mddev, struct md_rdev *rdev,
mddev_suspend(mddev);
if (!rdev)
- rdevs_init_serial(mddev);
+ ret = rdevs_init_serial(mddev);
else
- rdev_init_serial(rdev);
+ ret = rdev_init_serial(rdev);
+ if (ret)
+ goto abort;
if (mddev->serial_info_pool == NULL) {
unsigned int noio_flag;
@@ -186,9 +224,13 @@ void mddev_create_serial_pool(struct mddev *mddev, struct md_rdev *rdev,
mempool_create_kmalloc_pool(NR_SERIAL_INFOS,
sizeof(struct serial_info));
memalloc_noio_restore(noio_flag);
- if (!mddev->serial_info_pool)
+ if (!mddev->serial_info_pool) {
+ rdevs_uninit_serial(mddev);
pr_err("can't alloc memory pool for serialization\n");
+ }
}
+
+abort:
if (!is_suspend)
mddev_resume(mddev);
}
@@ -199,8 +241,8 @@ void mddev_create_serial_pool(struct mddev *mddev, struct md_rdev *rdev,
* 2. when bitmap is destroyed while policy is not enabled.
* 3. for disable policy, the pool is destroyed only when no rdev needs it.
*/
-static void mddev_destroy_serial_pool(struct mddev *mddev, struct md_rdev *rdev,
- bool is_suspend)
+void mddev_destroy_serial_pool(struct mddev *mddev, struct md_rdev *rdev,
+ bool is_suspend)
{
if (rdev && !test_bit(CollisionCheck, &rdev->flags))
return;
@@ -213,8 +255,9 @@ static void mddev_destroy_serial_pool(struct mddev *mddev, struct md_rdev *rdev,
mddev_suspend(mddev);
rdev_for_each(temp, mddev) {
if (!rdev) {
- if (!rdev_need_serial(temp))
- clear_bit(CollisionCheck, &temp->flags);
+ if (!mddev->serialize_policy ||
+ !rdev_need_serial(temp))
+ rdev_uninit_serial(temp);
else
num++;
} else if (temp != rdev &&
@@ -223,7 +266,7 @@ static void mddev_destroy_serial_pool(struct mddev *mddev, struct md_rdev *rdev,
}
if (rdev)
- clear_bit(CollisionCheck, &rdev->flags);
+ rdev_uninit_serial(rdev);
if (num)
pr_info("The mempool could be used by other devices\n");
@@ -6117,8 +6160,9 @@ static void __md_stop_writes(struct mddev *mddev)
mddev->in_sync = 1;
md_update_sb(mddev, 1);
}
- mempool_destroy(mddev->serial_info_pool);
- mddev->serial_info_pool = NULL;
+ /* disable policy to guarantee rdevs free resources for serialization */
+ mddev->serialize_policy = 0;
+ mddev_destroy_serial_pool(mddev, NULL, true);
}
void md_stop_writes(struct mddev *mddev)