On Mon, 19 May 2014 10:21:17 +0800 Shaohua Li <shli@xxxxxxxxxx> wrote:
> Ping!
Sorry, I've been busy. I'll try to look at this this week.
Thanks,
NeilBrown
>
> On Mon, May 12, 2014 at 09:16:59AM +0800, Shaohua Li wrote:
> >
> > For a full stripe write, the ideal operation order is handle_stripe_dirtying(),
> > raid_run_ops(), set R5_Wantwrite bit, and ops_run_io(). In this way, one
> > handle_stripe() will dispatch IO for the stripe, otherwise there are more extra
> > rounds of handle_stripe(). In a high speed raid5 array, handle_stripe()
> > consumes considered cpu time. Reducing its overhead has around 10% performance
> > boost.
> >
> > This patch makes handle_stripe() operations follow the ideal order. It also
> > moves handle_stripe_clean_event() up, as it handles completed stripe. And if I
> > don't change handle_stripe_clean_event() order, I saw some states confused with
> > other changes.
> >
> > Signed-off-by: Shaohua Li <shli@xxxxxxxxxxxx>
> > ---
> > drivers/md/raid5.c | 39 +++++++++++++++++++++------------------
> > 1 file changed, 21 insertions(+), 18 deletions(-)
> >
> > Index: linux/drivers/md/raid5.c
> > ===================================================================
> > --- linux.orig/drivers/md/raid5.c 2014-05-06 17:19:13.868225752 +0800
> > +++ linux/drivers/md/raid5.c 2014-05-06 17:20:25.367326852 +0800
> > @@ -1633,7 +1633,7 @@ static void ops_run_check_pq(struct stri
> > &sh->ops.zero_sum_result, percpu->spare_page, &submit);
> > }
> >
> > -static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
> > +static void raid_run_ops(struct stripe_head *sh, unsigned long *ops_request)
> > {
> > int overlap_clear = 0, i, disks = sh->disks;
> > struct dma_async_tx_descriptor *tx = NULL;
> > @@ -1644,12 +1644,12 @@ static void raid_run_ops(struct stripe_h
> >
> > cpu = get_cpu();
> > percpu = per_cpu_ptr(conf->percpu, cpu);
> > - if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
> > + if (test_and_clear_bit(STRIPE_OP_BIOFILL, ops_request)) {
> > ops_run_biofill(sh);
> > overlap_clear++;
> > }
> >
> > - if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
> > + if (test_and_clear_bit(STRIPE_OP_COMPUTE_BLK, ops_request)) {
> > if (level < 6)
> > tx = ops_run_compute5(sh, percpu);
> > else {
> > @@ -1659,26 +1659,26 @@ static void raid_run_ops(struct stripe_h
> > tx = ops_run_compute6_2(sh, percpu);
> > }
> > /* terminate the chain if reconstruct is not set to be run */
> > - if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
> > + if (tx && !test_and_clear_bit(STRIPE_OP_RECONSTRUCT, ops_request))
> > async_tx_ack(tx);
> > }
> >
> > - if (test_bit(STRIPE_OP_PREXOR, &ops_request))
> > + if (test_and_clear_bit(STRIPE_OP_PREXOR, ops_request))
> > tx = ops_run_prexor(sh, percpu, tx);
> >
> > - if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
> > + if (test_and_clear_bit(STRIPE_OP_BIODRAIN, ops_request)) {
> > tx = ops_run_biodrain(sh, tx);
> > overlap_clear++;
> > }
> >
> > - if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
> > + if (test_and_clear_bit(STRIPE_OP_RECONSTRUCT, ops_request)) {
> > if (level < 6)
> > ops_run_reconstruct5(sh, percpu, tx);
> > else
> > ops_run_reconstruct6(sh, percpu, tx);
> > }
> >
> > - if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
> > + if (test_and_clear_bit(STRIPE_OP_CHECK, ops_request)) {
> > if (sh->check_state == check_state_run)
> > ops_run_check_p(sh, percpu);
> > else if (sh->check_state == check_state_run_q)
> > @@ -3780,6 +3780,41 @@ static void handle_stripe(struct stripe_
> > handle_failed_sync(conf, sh, &s);
> > }
> >
> > + /*
> > + * might be able to return some write requests if the parity blocks
> > + * are safe, or on a failed drive
> > + */
> > + pdev = &sh->dev[sh->pd_idx];
> > + s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
> > + || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
> > + qdev = &sh->dev[sh->qd_idx];
> > + s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
> > + || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
> > + || conf->level < 6;
> > +
> > + if (s.written &&
> > + (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
> > + && !test_bit(R5_LOCKED, &pdev->flags)
> > + && (test_bit(R5_UPTODATE, &pdev->flags) ||
> > + test_bit(R5_Discard, &pdev->flags))))) &&
> > + (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
> > + && !test_bit(R5_LOCKED, &qdev->flags)
> > + && (test_bit(R5_UPTODATE, &qdev->flags) ||
> > + test_bit(R5_Discard, &qdev->flags))))))
> > + handle_stripe_clean_event(conf, sh, disks, &s.return_bi);
> > +
> > + /* Now to consider new write requests and what else, if anything
> > + * should be read. We do not handle new writes when:
> > + * 1/ A 'write' operation (copy+xor) is already in flight.
> > + * 2/ A 'check' operation is in flight, as it may clobber the parity
> > + * block.
> > + */
> > + if (s.to_write && !sh->reconstruct_state && !sh->check_state)
> > + handle_stripe_dirtying(conf, sh, &s, disks);
> > +
> > + if (s.ops_request)
> > + raid_run_ops(sh, &s.ops_request);
> > +
> > /* Now we check to see if any write operations have recently
> > * completed
> > */
> > @@ -3817,29 +3852,6 @@ static void handle_stripe(struct stripe_
> > s.dec_preread_active = 1;
> > }
> >
> > - /*
> > - * might be able to return some write requests if the parity blocks
> > - * are safe, or on a failed drive
> > - */
> > - pdev = &sh->dev[sh->pd_idx];
> > - s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
> > - || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
> > - qdev = &sh->dev[sh->qd_idx];
> > - s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
> > - || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
> > - || conf->level < 6;
> > -
> > - if (s.written &&
> > - (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
> > - && !test_bit(R5_LOCKED, &pdev->flags)
> > - && (test_bit(R5_UPTODATE, &pdev->flags) ||
> > - test_bit(R5_Discard, &pdev->flags))))) &&
> > - (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
> > - && !test_bit(R5_LOCKED, &qdev->flags)
> > - && (test_bit(R5_UPTODATE, &qdev->flags) ||
> > - test_bit(R5_Discard, &qdev->flags))))))
> > - handle_stripe_clean_event(conf, sh, disks, &s.return_bi);
> > -
> > /* Now we might consider reading some blocks, either to check/generate
> > * parity, or to satisfy requests
> > * or to load a block that is being partially written.
> > @@ -3851,15 +3863,6 @@ static void handle_stripe(struct stripe_
> > || s.expanding)
> > handle_stripe_fill(sh, &s, disks);
> >
> > - /* Now to consider new write requests and what else, if anything
> > - * should be read. We do not handle new writes when:
> > - * 1/ A 'write' operation (copy+xor) is already in flight.
> > - * 2/ A 'check' operation is in flight, as it may clobber the parity
> > - * block.
> > - */
> > - if (s.to_write && !sh->reconstruct_state && !sh->check_state)
> > - handle_stripe_dirtying(conf, sh, &s, disks);
> > -
> > /* maybe we need to check and possibly fix the parity for this stripe
> > * Any reads will already have been scheduled, so we just see if enough
> > * data is available. The parity check is held off while parity
> > @@ -4014,7 +4017,7 @@ finish:
> > }
> >
> > if (s.ops_request)
> > - raid_run_ops(sh, s.ops_request);
> > + raid_run_ops(sh, &s.ops_request);
> >
> > ops_run_io(sh, &s);
> >
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