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block/block-copy: increase buffered copy request
No reason to limit buffered copy to one cluster. Let's allow up to 1 MiB. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20191022111805.3432-7-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
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@ -21,6 +21,7 @@
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#include "qemu/units.h"
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#define BLOCK_COPY_MAX_COPY_RANGE (16 * MiB)
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#define BLOCK_COPY_MAX_BUFFER (1 * MiB)
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#define BLOCK_COPY_MAX_MEM (128 * MiB)
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static void coroutine_fn block_copy_wait_inflight_reqs(BlockCopyState *s,
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@ -75,10 +76,8 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
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{
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BlockCopyState *s;
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BdrvDirtyBitmap *copy_bitmap;
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/* Ignore BLOCK_COPY_MAX_COPY_RANGE if requested cluster_size is larger */
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uint32_t max_transfer =
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MIN_NON_ZERO(MAX(cluster_size, BLOCK_COPY_MAX_COPY_RANGE),
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MIN_NON_ZERO(INT_MAX,
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MIN_NON_ZERO(source->bs->bl.max_transfer,
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target->bs->bl.max_transfer));
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@ -100,17 +99,28 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
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.mem = shres_create(BLOCK_COPY_MAX_MEM),
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};
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s->copy_range_size = QEMU_ALIGN_DOWN(max_transfer, cluster_size),
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/*
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* Set use_copy_range, consider the following:
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* 1. Compression is not supported for copy_range.
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* 2. copy_range does not respect max_transfer (it's a TODO), so we factor
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* that in here. If max_transfer is smaller than the job->cluster_size,
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* we do not use copy_range (in that case it's zero after aligning down
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* above).
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*/
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s->use_copy_range =
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!(write_flags & BDRV_REQ_WRITE_COMPRESSED) && s->copy_range_size > 0;
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if (max_transfer < cluster_size) {
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/*
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* copy_range does not respect max_transfer. We don't want to bother
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* with requests smaller than block-copy cluster size, so fallback to
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* buffered copying (read and write respect max_transfer on their
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* behalf).
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*/
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s->use_copy_range = false;
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s->copy_size = cluster_size;
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} else if (write_flags & BDRV_REQ_WRITE_COMPRESSED) {
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/* Compression is not supported for copy_range */
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s->use_copy_range = false;
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s->copy_size = MAX(cluster_size, BLOCK_COPY_MAX_BUFFER);
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} else {
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/*
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* copy_range does not respect max_transfer (it's a TODO), so we factor
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* that in here.
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*/
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s->use_copy_range = true;
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s->copy_size = MIN(MAX(cluster_size, BLOCK_COPY_MAX_COPY_RANGE),
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QEMU_ALIGN_DOWN(max_transfer, cluster_size));
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}
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QLIST_INIT(&s->inflight_reqs);
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@ -156,12 +166,19 @@ static int coroutine_fn block_copy_do_copy(BlockCopyState *s,
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if (ret < 0) {
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trace_block_copy_copy_range_fail(s, start, ret);
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s->use_copy_range = false;
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s->copy_size = MAX(s->cluster_size, BLOCK_COPY_MAX_BUFFER);
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/* Fallback to read+write with allocated buffer */
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} else {
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goto out;
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}
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}
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/*
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* In case of failed copy_range request above, we may proceed with buffered
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* request larger than BLOCK_COPY_MAX_BUFFER. Still, further requests will
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* be properly limited, so don't care too much.
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*/
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bounce_buffer = qemu_blockalign(s->source->bs, nbytes);
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ret = bdrv_co_pread(s->source, start, nbytes, bounce_buffer, 0);
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@ -290,8 +307,7 @@ int coroutine_fn block_copy(BlockCopyState *s,
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continue; /* already copied */
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}
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chunk_end = MIN(end, start + (s->use_copy_range ?
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s->copy_range_size : s->cluster_size));
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chunk_end = MIN(end, start + s->copy_size);
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next_zero = bdrv_dirty_bitmap_next_zero(s->copy_bitmap, start,
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chunk_end - start);
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@ -38,7 +38,7 @@ typedef struct BlockCopyState {
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BdrvDirtyBitmap *copy_bitmap;
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int64_t cluster_size;
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bool use_copy_range;
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int64_t copy_range_size;
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int64_t copy_size;
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uint64_t len;
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QLIST_HEAD(, BlockCopyInFlightReq) inflight_reqs;
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