From d84e0f10d38393f617227f0c831a99c69294651f Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 2 Jan 2007 13:52:30 -0700 Subject: [PATCH] md: common infrastructure for running operations with raid5_run_ops All the handle_stripe operations that are to be transitioned to use raid5_run_ops need a method to coherently gather work under the stripe-lock and hand that work off to raid5_run_ops. The 'get_stripe_work' routine runs under the lock to read all the bits in sh->ops.pending that do not have the corresponding bit set in sh->ops.ack. This modified 'pending' bitmap is then passed to raid5_run_ops for processing. The transition from 'ack' to 'completion' does not need similar protection as the existing release_stripe infrastructure will guarantee that handle_stripe will run again after a completion bit is set, and handle_stripe can tolerate a sh->ops.completed bit being set while the lock is held. A call to async_tx_issue_pending_all() is added to raid5d to kick the offload engines once all pending stripe operations work has been submitted. This enables batching of the submission and completion of operations. Signed-off-by: Dan Williams Acked-By: NeilBrown --- drivers/md/raid5.c | 67 +++++++++++++++++++++++++++++++++++++++------- 1 file changed, 58 insertions(+), 9 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 0b7002479655..d89a25e7c17b 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -141,6 +141,7 @@ static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh) } md_wakeup_thread(conf->mddev->thread); } else { + BUG_ON(sh->ops.pending); if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { atomic_dec(&conf->preread_active_stripes); if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) @@ -242,7 +243,8 @@ static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int BUG_ON(atomic_read(&sh->count) != 0); BUG_ON(test_bit(STRIPE_HANDLE, &sh->state)); - + BUG_ON(sh->ops.pending || sh->ops.ack || sh->ops.complete); + CHECK_DEVLOCK(); pr_debug("init_stripe called, stripe %llu\n", (unsigned long long)sh->sector); @@ -258,11 +260,11 @@ static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int for (i = sh->disks; i--; ) { struct r5dev *dev = &sh->dev[i]; - if (dev->toread || dev->towrite || dev->written || + if (dev->toread || dev->read || dev->towrite || dev->written || test_bit(R5_LOCKED, &dev->flags)) { - printk("sector=%llx i=%d %p %p %p %d\n", + printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n", (unsigned long long)sh->sector, i, dev->toread, - dev->towrite, dev->written, + dev->read, dev->towrite, dev->written, test_bit(R5_LOCKED, &dev->flags)); BUG(); } @@ -342,6 +344,44 @@ static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector return sh; } +/* test_and_ack_op() ensures that we only dequeue an operation once */ +#define test_and_ack_op(op, pend) \ +do { \ + if (test_bit(op, &sh->ops.pending) && \ + !test_bit(op, &sh->ops.complete)) { \ + if (test_and_set_bit(op, &sh->ops.ack)) \ + clear_bit(op, &pend); \ + else \ + ack++; \ + } else \ + clear_bit(op, &pend); \ +} while (0) + +/* find new work to run, do not resubmit work that is already + * in flight + */ +static unsigned long get_stripe_work(struct stripe_head *sh) +{ + unsigned long pending; + int ack = 0; + + pending = sh->ops.pending; + + test_and_ack_op(STRIPE_OP_BIOFILL, pending); + test_and_ack_op(STRIPE_OP_COMPUTE_BLK, pending); + test_and_ack_op(STRIPE_OP_PREXOR, pending); + test_and_ack_op(STRIPE_OP_BIODRAIN, pending); + test_and_ack_op(STRIPE_OP_POSTXOR, pending); + test_and_ack_op(STRIPE_OP_CHECK, pending); + if (test_and_clear_bit(STRIPE_OP_IO, &sh->ops.pending)) + ack++; + + sh->ops.count -= ack; + BUG_ON(sh->ops.count < 0); + + return pending; +} + static int raid5_end_read_request(struct bio *bi, unsigned int bytes_done, int error); static int @@ -2494,7 +2534,6 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh, * schedule a write of some buffers * return confirmation of parity correctness * - * Parity calculations are done inside the stripe lock * buffers are taken off read_list or write_list, and bh_cache buffers * get BH_Lock set before the stripe lock is released. * @@ -2507,11 +2546,13 @@ static void handle_stripe5(struct stripe_head *sh) struct bio *return_bi = NULL; struct stripe_head_state s; struct r5dev *dev; + unsigned long pending = 0; memset(&s, 0, sizeof(s)); - pr_debug("handling stripe %llu, cnt=%d, pd_idx=%d\n", - (unsigned long long)sh->sector, atomic_read(&sh->count), - sh->pd_idx); + pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d " + "ops=%lx:%lx:%lx\n", (unsigned long long)sh->sector, sh->state, + atomic_read(&sh->count), sh->pd_idx, + sh->ops.pending, sh->ops.ack, sh->ops.complete); spin_lock(&sh->lock); clear_bit(STRIPE_HANDLE, &sh->state); @@ -2674,8 +2715,14 @@ static void handle_stripe5(struct stripe_head *sh) if (s.expanding && s.locked == 0) handle_stripe_expansion(conf, sh, NULL); + if (sh->ops.count) + pending = get_stripe_work(sh); + spin_unlock(&sh->lock); + if (pending) + raid5_run_ops(sh, pending); + return_io(return_bi); for (i=disks; i-- ;) { @@ -3798,8 +3845,10 @@ static void raid5d (mddev_t *mddev) handled++; } - if (list_empty(&conf->handle_list)) + if (list_empty(&conf->handle_list)) { + async_tx_issue_pending_all(); break; + } first = conf->handle_list.next; sh = list_entry(first, struct stripe_head, lru); -- 2.20.1