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Commit ae1713e2 authored by Artur Paszkiewicz's avatar Artur Paszkiewicz Committed by Shaohua Li
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raid5-ppl: partial parity calculation optimization 



In case of read-modify-write, partial partity is the same as the result
of ops_run_prexor5(), so we can just copy sh->dev[pd_idx].page into
sh->ppl_page instead of calculating it again.

Signed-off-by: default avatarArtur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent 845b9e22

drivers/md/raid5-ppl.c

+10 −10
Original line number Diff line number Diff line
@@ -153,7 +153,7 @@ ops_run_partial_parity(struct stripe_head *sh, struct raid5_percpu *percpu, 
		       struct dma_async_tx_descriptor *tx)

{

	int disks = sh->disks;

	struct page **xor_srcs = flex_array_get(percpu->scribble, 0);

	struct page **srcs = flex_array_get(percpu->scribble, 0);

	int count = 0, pd_idx = sh->pd_idx, i;

	struct async_submit_ctl submit;
@@ -166,18 +166,18 @@ ops_run_partial_parity(struct stripe_head *sh, struct raid5_percpu *percpu, 
	 * differently.

	 */

	if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {

		/* rmw: xor old data and parity from updated disks */

		for (i = disks; i--;) {

			struct r5dev *dev = &sh->dev[i];

			if (test_bit(R5_Wantdrain, &dev->flags) || i == pd_idx)

				xor_srcs[count++] = dev->page;

		}

		/*

		 * rmw: xor old data and parity from updated disks

		 * This is calculated earlier by ops_run_prexor5() so just copy

		 * the parity dev page.

		 */

		srcs[count++] = sh->dev[pd_idx].page;

	} else if (sh->reconstruct_state == reconstruct_state_drain_run) {

		/* rcw: xor data from all not updated disks */

		for (i = disks; i--;) {

			struct r5dev *dev = &sh->dev[i];

			if (test_bit(R5_UPTODATE, &dev->flags))

				xor_srcs[count++] = dev->page;

				srcs[count++] = dev->page;

		}

	} else {

		return tx;
@@ -188,10 +188,10 @@ ops_run_partial_parity(struct stripe_head *sh, struct raid5_percpu *percpu, 
			  + sizeof(struct page *) * (sh->disks + 2));



	if (count == 1)

		tx = async_memcpy(sh->ppl_page, xor_srcs[0], 0, 0, PAGE_SIZE,

		tx = async_memcpy(sh->ppl_page, srcs[0], 0, 0, PAGE_SIZE,

				  &submit);

	else

		tx = async_xor(sh->ppl_page, xor_srcs, 0, count, PAGE_SIZE,

		tx = async_xor(sh->ppl_page, srcs, 0, count, PAGE_SIZE,

			       &submit);



	return tx;

drivers/md/raid5.c

+3 −3
Original line number Diff line number Diff line
@@ -2079,9 +2079,6 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request) 
			async_tx_ack(tx);

	}



	if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))

		tx = ops_run_partial_parity(sh, percpu, tx);



	if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {

		if (level < 6)

			tx = ops_run_prexor5(sh, percpu, tx);
@@ -2089,6 +2086,9 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request) 
			tx = ops_run_prexor6(sh, percpu, tx);

	}



	if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))

		tx = ops_run_partial_parity(sh, percpu, tx);



	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {

		tx = ops_run_biodrain(sh, tx);

		overlap_clear++;