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authorGuoqing Jiang <gqjiang@suse.com>2017-10-24 09:11:52 +0200
committerShaohua Li <shli@fb.com>2017-11-02 05:32:23 +0100
commit8db87912c9a8771c53b98845cd5516ea63b22e1e (patch)
treeea7749f6fbd11a75218e9710f8298c3fe5766d31
parentmd-cluster: Suspend writes in RAID10 if within range (diff)
downloadlinux-8db87912c9a8771c53b98845cd5516ea63b22e1e.tar.xz
linux-8db87912c9a8771c53b98845cd5516ea63b22e1e.zip
md-cluster: Use a small window for raid10 resync
Suspending the entire device for resync could take too long. Resync in small chunks. cluster's resync window is maintained in r10conf as cluster_sync_low and cluster_sync_high, and processed in raid10's sync_request(). If the current resync is outside the cluster resync window: 1. Set the cluster_sync_low to curr_resync_completed. 2. Set cluster_sync_high to cluster_sync_low + stripe size. 3. Send a message to all nodes so they may add it in their suspension list. Note: We only support "near" raid10 so far, resync a far or offset raid10 array could have trouble. So raid10_run checks the layout of clustered raid10, it will refuse to run if the layout is not correct. With the "near" layout we process one stripe at a time progressing monotonically through the address space. So we can have a sliding window of whole-stripes which moves through the array suspending IO on other nodes, and both resync which uses array addresses and recovery which uses device addresses can stay within this window. Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
-rw-r--r--drivers/md/raid10.c113
-rw-r--r--drivers/md/raid10.h6
2 files changed, 118 insertions, 1 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index cc6a56a659a3..b9edbc747a95 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -136,10 +136,13 @@ static void r10bio_pool_free(void *r10_bio, void *data)
kfree(r10_bio);
}
+#define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
/* amount of memory to reserve for resync requests */
#define RESYNC_WINDOW (1024*1024)
/* maximum number of concurrent requests, memory permitting */
#define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE)
+#define CLUSTER_RESYNC_WINDOW (16 * RESYNC_WINDOW)
+#define CLUSTER_RESYNC_WINDOW_SECTORS (CLUSTER_RESYNC_WINDOW >> 9)
/*
* When performing a resync, we need to read and compare, so
@@ -2841,6 +2844,43 @@ static struct r10bio *raid10_alloc_init_r10buf(struct r10conf *conf)
}
/*
+ * Set cluster_sync_high since we need other nodes to add the
+ * range [cluster_sync_low, cluster_sync_high] to suspend list.
+ */
+static void raid10_set_cluster_sync_high(struct r10conf *conf)
+{
+ sector_t window_size;
+ int extra_chunk, chunks;
+
+ /*
+ * First, here we define "stripe" as a unit which across
+ * all member devices one time, so we get chunks by use
+ * raid_disks / near_copies. Otherwise, if near_copies is
+ * close to raid_disks, then resync window could increases
+ * linearly with the increase of raid_disks, which means
+ * we will suspend a really large IO window while it is not
+ * necessary. If raid_disks is not divisible by near_copies,
+ * an extra chunk is needed to ensure the whole "stripe" is
+ * covered.
+ */
+
+ chunks = conf->geo.raid_disks / conf->geo.near_copies;
+ if (conf->geo.raid_disks % conf->geo.near_copies == 0)
+ extra_chunk = 0;
+ else
+ extra_chunk = 1;
+ window_size = (chunks + extra_chunk) * conf->mddev->chunk_sectors;
+
+ /*
+ * At least use a 32M window to align with raid1's resync window
+ */
+ window_size = (CLUSTER_RESYNC_WINDOW_SECTORS > window_size) ?
+ CLUSTER_RESYNC_WINDOW_SECTORS : window_size;
+
+ conf->cluster_sync_high = conf->cluster_sync_low + window_size;
+}
+
+/*
* perform a "sync" on one "block"
*
* We need to make sure that no normal I/O request - particularly write
@@ -2912,6 +2952,9 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
max_sector = mddev->resync_max_sectors;
if (sector_nr >= max_sector) {
+ conf->cluster_sync_low = 0;
+ conf->cluster_sync_high = 0;
+
/* If we aborted, we need to abort the
* sync on the 'current' bitmap chucks (there can
* be several when recovering multiple devices).
@@ -3266,7 +3309,17 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
/* resync. Schedule a read for every block at this virt offset */
int count = 0;
- bitmap_cond_end_sync(mddev->bitmap, sector_nr, 0);
+ /*
+ * Since curr_resync_completed could probably not update in
+ * time, and we will set cluster_sync_low based on it.
+ * Let's check against "sector_nr + 2 * RESYNC_SECTORS" for
+ * safety reason, which ensures curr_resync_completed is
+ * updated in bitmap_cond_end_sync.
+ */
+ bitmap_cond_end_sync(mddev->bitmap, sector_nr,
+ mddev_is_clustered(mddev) &&
+ (sector_nr + 2 * RESYNC_SECTORS >
+ conf->cluster_sync_high));
if (!bitmap_start_sync(mddev->bitmap, sector_nr,
&sync_blocks, mddev->degraded) &&
@@ -3400,6 +3453,52 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
} while (++page_idx < RESYNC_PAGES);
r10_bio->sectors = nr_sectors;
+ if (mddev_is_clustered(mddev) &&
+ test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
+ /* It is resync not recovery */
+ if (conf->cluster_sync_high < sector_nr + nr_sectors) {
+ conf->cluster_sync_low = mddev->curr_resync_completed;
+ raid10_set_cluster_sync_high(conf);
+ /* Send resync message */
+ md_cluster_ops->resync_info_update(mddev,
+ conf->cluster_sync_low,
+ conf->cluster_sync_high);
+ }
+ } else if (mddev_is_clustered(mddev)) {
+ /* This is recovery not resync */
+ sector_t sect_va1, sect_va2;
+ bool broadcast_msg = false;
+
+ for (i = 0; i < conf->geo.raid_disks; i++) {
+ /*
+ * sector_nr is a device address for recovery, so we
+ * need translate it to array address before compare
+ * with cluster_sync_high.
+ */
+ sect_va1 = raid10_find_virt(conf, sector_nr, i);
+
+ if (conf->cluster_sync_high < sect_va1 + nr_sectors) {
+ broadcast_msg = true;
+ /*
+ * curr_resync_completed is similar as
+ * sector_nr, so make the translation too.
+ */
+ sect_va2 = raid10_find_virt(conf,
+ mddev->curr_resync_completed, i);
+
+ if (conf->cluster_sync_low == 0 ||
+ conf->cluster_sync_low > sect_va2)
+ conf->cluster_sync_low = sect_va2;
+ }
+ }
+ if (broadcast_msg) {
+ raid10_set_cluster_sync_high(conf);
+ md_cluster_ops->resync_info_update(mddev,
+ conf->cluster_sync_low,
+ conf->cluster_sync_high);
+ }
+ }
+
while (biolist) {
bio = biolist;
biolist = biolist->bi_next;
@@ -3659,6 +3758,18 @@ static int raid10_run(struct mddev *mddev)
if (!conf)
goto out;
+ if (mddev_is_clustered(conf->mddev)) {
+ int fc, fo;
+
+ fc = (mddev->layout >> 8) & 255;
+ fo = mddev->layout & (1<<16);
+ if (fc > 1 || fo > 0) {
+ pr_err("only near layout is supported by clustered"
+ " raid10\n");
+ goto out;
+ }
+ }
+
mddev->thread = conf->thread;
conf->thread = NULL;
diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index 735ce1a3d260..2bef4e8789c8 100644
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -88,6 +88,12 @@ struct r10conf {
* the new thread here until we fully activate the array.
*/
struct md_thread *thread;
+
+ /*
+ * Keep track of cluster resync window to send to other nodes.
+ */
+ sector_t cluster_sync_low;
+ sector_t cluster_sync_high;
};
/*