Ping!
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);
>
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
