md/raid5: activate raid6 rmw feature
Glue it altogehter. The raid6 rmw path should work the same as the
already existing raid5 logic. So emulate the prexor handling/flags
and split functions as needed.
1) Enable xor_syndrome() in the async layer.
2) Split ops_run_prexor() into RAID4/5 and RAID6 logic. Xor the syndrome
at the start of a rmw run as we did it before for the single parity.
3) Take care of rmw run in ops_run_reconstruct6(). Again process only
the changed pages to get syndrome back into sync.
4) Enhance set_syndrome_sources() to fill NULL pages if we are in a rmw
run. The lower layers will calculate start & end pages from that and
call the xor_syndrome() correspondingly.
5) Adapt the several places where we ignored Q handling up to now.
Performance numbers for a single E5630 system with a mix of 10 7200k
desktop/server disks. 300 seconds random write with 8 threads onto a
3,2TB (10*400GB) RAID6 64K chunk without spare (group_thread_cnt=4)
bsize rmw_level=1 rmw_level=0 rmw_level=1 rmw_level=0
skip_copy=1 skip_copy=1 skip_copy=0 skip_copy=0
4K 115 KB/s 141 KB/s 165 KB/s 140 KB/s
8K 225 KB/s 275 KB/s 324 KB/s 274 KB/s
16K 434 KB/s 536 KB/s 640 KB/s 534 KB/s
32K 751 KB/s 1,051 KB/s 1,234 KB/s 1,045 KB/s
64K 1,339 KB/s 1,958 KB/s 2,282 KB/s 1,962 KB/s
128K 2,673 KB/s 3,862 KB/s 4,113 KB/s 3,898 KB/s
256K 7,685 KB/s 7,539 KB/s 7,557 KB/s 7,638 KB/s
512K 19,556 KB/s 19,558 KB/s 19,652 KB/s 19,688 Kb/s
Signed-off-by: Markus Stockhausen <stockhausen@collogia.de>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index d05327c..5d355e0 100644
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -124,6 +124,7 @@
{
void **srcs;
int i;
+ int start = -1, stop = disks - 3;
if (submit->scribble)
srcs = submit->scribble;
@@ -134,10 +135,21 @@
if (blocks[i] == NULL) {
BUG_ON(i > disks - 3); /* P or Q can't be zero */
srcs[i] = (void*)raid6_empty_zero_page;
- } else
+ } else {
srcs[i] = page_address(blocks[i]) + offset;
+ if (i < disks - 2) {
+ stop = i;
+ if (start == -1)
+ start = i;
+ }
+ }
}
- raid6_call.gen_syndrome(disks, len, srcs);
+ if (submit->flags & ASYNC_TX_PQ_XOR_DST) {
+ BUG_ON(!raid6_call.xor_syndrome);
+ if (start >= 0)
+ raid6_call.xor_syndrome(disks, start, stop, len, srcs);
+ } else
+ raid6_call.gen_syndrome(disks, len, srcs);
async_tx_sync_epilog(submit);
}
@@ -178,7 +190,8 @@
if (device)
unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOIO);
- if (unmap &&
+ /* XORing P/Q is only implemented in software */
+ if (unmap && !(submit->flags & ASYNC_TX_PQ_XOR_DST) &&
(src_cnt <= dma_maxpq(device, 0) ||
dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
is_dma_pq_aligned(device, offset, 0, len)) {
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 3ae097d..c82ce1f 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1317,7 +1317,9 @@
* destination buffer is recorded in srcs[count] and the Q destination
* is recorded in srcs[count+1]].
*/
-static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh)
+static int set_syndrome_sources(struct page **srcs,
+ struct stripe_head *sh,
+ int srctype)
{
int disks = sh->disks;
int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
@@ -1332,8 +1334,15 @@
i = d0_idx;
do {
int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
+ struct r5dev *dev = &sh->dev[i];
- srcs[slot] = sh->dev[i].page;
+ if (i == sh->qd_idx || i == sh->pd_idx ||
+ (srctype == SYNDROME_SRC_ALL) ||
+ (srctype == SYNDROME_SRC_WANT_DRAIN &&
+ test_bit(R5_Wantdrain, &dev->flags)) ||
+ (srctype == SYNDROME_SRC_WRITTEN &&
+ dev->written))
+ srcs[slot] = sh->dev[i].page;
i = raid6_next_disk(i, disks);
} while (i != d0_idx);
@@ -1373,7 +1382,7 @@
atomic_inc(&sh->count);
if (target == qd_idx) {
- count = set_syndrome_sources(blocks, sh);
+ count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
blocks[count] = NULL; /* regenerating p is not necessary */
BUG_ON(blocks[count+1] != dest); /* q should already be set */
init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
@@ -1481,7 +1490,7 @@
tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
&submit);
- count = set_syndrome_sources(blocks, sh);
+ count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
init_async_submit(&submit, ASYNC_TX_FENCE, tx,
ops_complete_compute, sh,
to_addr_conv(sh, percpu, 0));
@@ -1515,8 +1524,8 @@
}
static struct dma_async_tx_descriptor *
-ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu,
- struct dma_async_tx_descriptor *tx)
+ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
+ struct dma_async_tx_descriptor *tx)
{
int disks = sh->disks;
struct page **xor_srcs = to_addr_page(percpu, 0);
@@ -1545,6 +1554,26 @@
}
static struct dma_async_tx_descriptor *
+ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
+ struct dma_async_tx_descriptor *tx)
+{
+ struct page **blocks = to_addr_page(percpu, 0);
+ int count;
+ struct async_submit_ctl submit;
+
+ pr_debug("%s: stripe %llu\n", __func__,
+ (unsigned long long)sh->sector);
+
+ count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
+
+ init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
+ ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
+ tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
+
+ return tx;
+}
+
+static struct dma_async_tx_descriptor *
ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
{
int disks = sh->disks;
@@ -1746,6 +1775,8 @@
int count, i, j = 0;
struct stripe_head *head_sh = sh;
int last_stripe;
+ int synflags;
+ unsigned long txflags;
pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
@@ -1765,14 +1796,23 @@
again:
blocks = to_addr_page(percpu, j);
- count = set_syndrome_sources(blocks, sh);
+
+ if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
+ synflags = SYNDROME_SRC_WRITTEN;
+ txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
+ } else {
+ synflags = SYNDROME_SRC_ALL;
+ txflags = ASYNC_TX_ACK;
+ }
+
+ count = set_syndrome_sources(blocks, sh, synflags);
last_stripe = !head_sh->batch_head ||
list_first_entry(&sh->batch_list,
struct stripe_head, batch_list) == head_sh;
if (last_stripe) {
atomic_inc(&head_sh->count);
- init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_reconstruct,
+ init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
head_sh, to_addr_conv(sh, percpu, j));
} else
init_async_submit(&submit, 0, tx, NULL, NULL,
@@ -1843,7 +1883,7 @@
(unsigned long long)sh->sector, checkp);
BUG_ON(sh->batch_head);
- count = set_syndrome_sources(srcs, sh);
+ count = set_syndrome_sources(srcs, sh, SYNDROME_SRC_ALL);
if (!checkp)
srcs[count] = NULL;
@@ -1884,8 +1924,12 @@
async_tx_ack(tx);
}
- if (test_bit(STRIPE_OP_PREXOR, &ops_request))
- tx = ops_run_prexor(sh, percpu, tx);
+ if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
+ if (level < 6)
+ tx = ops_run_prexor5(sh, percpu, tx);
+ else
+ tx = ops_run_prexor6(sh, percpu, tx);
+ }
if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
tx = ops_run_biodrain(sh, tx);
@@ -2770,7 +2814,7 @@
schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
int rcw, int expand)
{
- int i, pd_idx = sh->pd_idx, disks = sh->disks;
+ int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
struct r5conf *conf = sh->raid_conf;
int level = conf->level;
@@ -2806,13 +2850,15 @@
if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
atomic_inc(&conf->pending_full_writes);
} else {
- BUG_ON(level == 6);
BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
+ BUG_ON(level == 6 &&
+ (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
+ test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
- if (i == pd_idx)
+ if (i == pd_idx || i == qd_idx)
continue;
if (dev->towrite &&
@@ -3476,28 +3522,27 @@
int rmw = 0, rcw = 0, i;
sector_t recovery_cp = conf->mddev->recovery_cp;
- /* RAID6 requires 'rcw' in current implementation.
- * Otherwise, check whether resync is now happening or should start.
+ /* Check whether resync is now happening or should start.
* If yes, then the array is dirty (after unclean shutdown or
* initial creation), so parity in some stripes might be inconsistent.
* In this case, we need to always do reconstruct-write, to ensure
* that in case of drive failure or read-error correction, we
* generate correct data from the parity.
*/
- if (conf->max_degraded == 2 ||
+ if (conf->rmw_level == PARITY_DISABLE_RMW ||
(recovery_cp < MaxSector && sh->sector >= recovery_cp &&
s->failed == 0)) {
/* Calculate the real rcw later - for now make it
* look like rcw is cheaper
*/
rcw = 1; rmw = 2;
- pr_debug("force RCW max_degraded=%u, recovery_cp=%llu sh->sector=%llu\n",
- conf->max_degraded, (unsigned long long)recovery_cp,
+ pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
+ conf->rmw_level, (unsigned long long)recovery_cp,
(unsigned long long)sh->sector);
} else for (i = disks; i--; ) {
/* would I have to read this buffer for read_modify_write */
struct r5dev *dev = &sh->dev[i];
- if ((dev->towrite || i == sh->pd_idx) &&
+ if ((dev->towrite || i == sh->pd_idx || i == sh->qd_idx) &&
!test_bit(R5_LOCKED, &dev->flags) &&
!(test_bit(R5_UPTODATE, &dev->flags) ||
test_bit(R5_Wantcompute, &dev->flags))) {
@@ -3507,7 +3552,8 @@
rmw += 2*disks; /* cannot read it */
}
/* Would I have to read this buffer for reconstruct_write */
- if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
+ if (!test_bit(R5_OVERWRITE, &dev->flags) &&
+ i != sh->pd_idx && i != sh->qd_idx &&
!test_bit(R5_LOCKED, &dev->flags) &&
!(test_bit(R5_UPTODATE, &dev->flags) ||
test_bit(R5_Wantcompute, &dev->flags))) {
@@ -3520,7 +3566,7 @@
pr_debug("for sector %llu, rmw=%d rcw=%d\n",
(unsigned long long)sh->sector, rmw, rcw);
set_bit(STRIPE_HANDLE, &sh->state);
- if (rmw < rcw && rmw > 0) {
+ if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_ENABLE_RMW)) && rmw > 0) {
/* prefer read-modify-write, but need to get some data */
if (conf->mddev->queue)
blk_add_trace_msg(conf->mddev->queue,
@@ -3528,7 +3574,7 @@
(unsigned long long)sh->sector, rmw);
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
- if ((dev->towrite || i == sh->pd_idx) &&
+ if ((dev->towrite || i == sh->pd_idx || i == sh->qd_idx) &&
!test_bit(R5_LOCKED, &dev->flags) &&
!(test_bit(R5_UPTODATE, &dev->flags) ||
test_bit(R5_Wantcompute, &dev->flags)) &&
@@ -3547,7 +3593,7 @@
}
}
}
- if (rcw <= rmw && rcw > 0) {
+ if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_ENABLE_RMW)) && rcw > 0) {
/* want reconstruct write, but need to get some data */
int qread =0;
rcw = 0;
@@ -6344,10 +6390,16 @@
}
conf->level = mddev->new_level;
- if (conf->level == 6)
+ if (conf->level == 6) {
conf->max_degraded = 2;
- else
+ if (raid6_call.xor_syndrome)
+ conf->rmw_level = PARITY_ENABLE_RMW;
+ else
+ conf->rmw_level = PARITY_DISABLE_RMW;
+ } else {
conf->max_degraded = 1;
+ conf->rmw_level = PARITY_ENABLE_RMW;
+ }
conf->algorithm = mddev->new_layout;
conf->reshape_progress = mddev->reshape_position;
if (conf->reshape_progress != MaxSector) {
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index ee65ed8..57fef9b 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -355,6 +355,23 @@
STRIPE_OP_RECONSTRUCT,
STRIPE_OP_CHECK,
};
+
+/*
+ * RAID parity calculation preferences
+ */
+enum {
+ PARITY_DISABLE_RMW = 0,
+ PARITY_ENABLE_RMW,
+};
+
+/*
+ * Pages requested from set_syndrome_sources()
+ */
+enum {
+ SYNDROME_SRC_ALL,
+ SYNDROME_SRC_WANT_DRAIN,
+ SYNDROME_SRC_WRITTEN,
+};
/*
* Plugging:
*
@@ -411,7 +428,7 @@
spinlock_t hash_locks[NR_STRIPE_HASH_LOCKS];
struct mddev *mddev;
int chunk_sectors;
- int level, algorithm;
+ int level, algorithm, rmw_level;
int max_degraded;
int raid_disks;
int max_nr_stripes;
diff --git a/include/linux/async_tx.h b/include/linux/async_tx.h
index 179b38f..388574e 100644
--- a/include/linux/async_tx.h
+++ b/include/linux/async_tx.h
@@ -60,12 +60,15 @@
* dependency chain
* @ASYNC_TX_FENCE: specify that the next operation in the dependency
* chain uses this operation's result as an input
+ * @ASYNC_TX_PQ_XOR_DST: do not overwrite the syndrome but XOR it with the
+ * input data. Required for rmw case.
*/
enum async_tx_flags {
ASYNC_TX_XOR_ZERO_DST = (1 << 0),
ASYNC_TX_XOR_DROP_DST = (1 << 1),
ASYNC_TX_ACK = (1 << 2),
ASYNC_TX_FENCE = (1 << 3),
+ ASYNC_TX_PQ_XOR_DST = (1 << 4),
};
/**