forked from mirrors/linux
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>
This commit is contained in:
Guoqing Jiang
Shaohua Li
parent
cb8a7a7e10
commit
8db87912c9
2 changed files with 118 additions and 1 deletions
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@ -136,10 +136,13 @@ static void r10bio_pool_free(void *r10_bio, void *data)
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kfree(r10_bio);
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}
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#define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
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/* amount of memory to reserve for resync requests */
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#define RESYNC_WINDOW (1024*1024)
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/* maximum number of concurrent requests, memory permitting */
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#define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE)
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#define CLUSTER_RESYNC_WINDOW (16 * RESYNC_WINDOW)
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#define CLUSTER_RESYNC_WINDOW_SECTORS (CLUSTER_RESYNC_WINDOW >> 9)
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/*
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* When performing a resync, we need to read and compare, so
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@ -2840,6 +2843,43 @@ static struct r10bio *raid10_alloc_init_r10buf(struct r10conf *conf)
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return r10bio;
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}
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/*
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* Set cluster_sync_high since we need other nodes to add the
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* range [cluster_sync_low, cluster_sync_high] to suspend list.
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*/
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static void raid10_set_cluster_sync_high(struct r10conf *conf)
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{
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sector_t window_size;
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int extra_chunk, chunks;
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/*
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* First, here we define "stripe" as a unit which across
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* all member devices one time, so we get chunks by use
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* raid_disks / near_copies. Otherwise, if near_copies is
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* close to raid_disks, then resync window could increases
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* linearly with the increase of raid_disks, which means
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* we will suspend a really large IO window while it is not
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* necessary. If raid_disks is not divisible by near_copies,
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* an extra chunk is needed to ensure the whole "stripe" is
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* covered.
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*/
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chunks = conf->geo.raid_disks / conf->geo.near_copies;
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if (conf->geo.raid_disks % conf->geo.near_copies == 0)
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extra_chunk = 0;
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else
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extra_chunk = 1;
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window_size = (chunks + extra_chunk) * conf->mddev->chunk_sectors;
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/*
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* At least use a 32M window to align with raid1's resync window
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*/
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window_size = (CLUSTER_RESYNC_WINDOW_SECTORS > window_size) ?
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CLUSTER_RESYNC_WINDOW_SECTORS : window_size;
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conf->cluster_sync_high = conf->cluster_sync_low + window_size;
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}
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/*
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* perform a "sync" on one "block"
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*
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@ -2912,6 +2952,9 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
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test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
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max_sector = mddev->resync_max_sectors;
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if (sector_nr >= max_sector) {
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conf->cluster_sync_low = 0;
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conf->cluster_sync_high = 0;
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/* If we aborted, we need to abort the
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* sync on the 'current' bitmap chucks (there can
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* be several when recovering multiple devices).
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@ -3266,7 +3309,17 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
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/* resync. Schedule a read for every block at this virt offset */
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int count = 0;
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bitmap_cond_end_sync(mddev->bitmap, sector_nr, 0);
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/*
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* Since curr_resync_completed could probably not update in
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* time, and we will set cluster_sync_low based on it.
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* Let's check against "sector_nr + 2 * RESYNC_SECTORS" for
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* safety reason, which ensures curr_resync_completed is
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* updated in bitmap_cond_end_sync.
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*/
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bitmap_cond_end_sync(mddev->bitmap, sector_nr,
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mddev_is_clustered(mddev) &&
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(sector_nr + 2 * RESYNC_SECTORS >
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conf->cluster_sync_high));
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if (!bitmap_start_sync(mddev->bitmap, sector_nr,
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&sync_blocks, mddev->degraded) &&
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@ -3400,6 +3453,52 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
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} while (++page_idx < RESYNC_PAGES);
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r10_bio->sectors = nr_sectors;
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if (mddev_is_clustered(mddev) &&
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test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
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/* It is resync not recovery */
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if (conf->cluster_sync_high < sector_nr + nr_sectors) {
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conf->cluster_sync_low = mddev->curr_resync_completed;
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raid10_set_cluster_sync_high(conf);
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/* Send resync message */
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md_cluster_ops->resync_info_update(mddev,
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conf->cluster_sync_low,
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conf->cluster_sync_high);
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}
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} else if (mddev_is_clustered(mddev)) {
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/* This is recovery not resync */
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sector_t sect_va1, sect_va2;
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bool broadcast_msg = false;
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for (i = 0; i < conf->geo.raid_disks; i++) {
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/*
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* sector_nr is a device address for recovery, so we
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* need translate it to array address before compare
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* with cluster_sync_high.
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*/
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sect_va1 = raid10_find_virt(conf, sector_nr, i);
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if (conf->cluster_sync_high < sect_va1 + nr_sectors) {
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broadcast_msg = true;
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/*
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* curr_resync_completed is similar as
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* sector_nr, so make the translation too.
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*/
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sect_va2 = raid10_find_virt(conf,
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mddev->curr_resync_completed, i);
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if (conf->cluster_sync_low == 0 ||
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conf->cluster_sync_low > sect_va2)
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conf->cluster_sync_low = sect_va2;
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}
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}
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if (broadcast_msg) {
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raid10_set_cluster_sync_high(conf);
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md_cluster_ops->resync_info_update(mddev,
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conf->cluster_sync_low,
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conf->cluster_sync_high);
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}
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}
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while (biolist) {
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bio = biolist;
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biolist = biolist->bi_next;
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@ -3659,6 +3758,18 @@ static int raid10_run(struct mddev *mddev)
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if (!conf)
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goto out;
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if (mddev_is_clustered(conf->mddev)) {
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int fc, fo;
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fc = (mddev->layout >> 8) & 255;
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fo = mddev->layout & (1<<16);
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if (fc > 1 || fo > 0) {
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pr_err("only near layout is supported by clustered"
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" raid10\n");
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goto out;
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}
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}
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mddev->thread = conf->thread;
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conf->thread = NULL;
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@ -88,6 +88,12 @@ struct r10conf {
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* the new thread here until we fully activate the array.
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*/
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struct md_thread *thread;
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/*
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* Keep track of cluster resync window to send to other nodes.
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*/
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sector_t cluster_sync_low;
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sector_t cluster_sync_high;
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};
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/*
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