forked from SLFO-pool/xen
125 lines
4.7 KiB
Diff
125 lines
4.7 KiB
Diff
From: Olaf Hering <olaf@aepfle.de>
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Date: Fri, 23 Oct 2020 11:30:41 +0200
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Subject: libxc sr save iov
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tools: save: preallocate iov array
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Remove repeated allocation from migration loop. There will never be
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more than MAX_BATCH_SIZE pages to process in a batch.
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Allocate the space once.
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Signed-off-by: Olaf Hering <olaf@aepfle.de>
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---
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tools/libs/guest/xg_sr_common.h | 1 +
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tools/libs/guest/xg_sr_save.c | 34 ++++++++++++++++-----------------
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2 files changed, 18 insertions(+), 17 deletions(-)
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--- a/tools/libs/guest/xg_sr_common.h
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+++ b/tools/libs/guest/xg_sr_common.h
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@@ -247,6 +247,7 @@ struct xc_sr_context
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xen_pfn_t *mfns;
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xen_pfn_t *types;
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int *errors;
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+ struct iovec *iov;
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unsigned int nr_batch_pfns;
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unsigned long *deferred_pages;
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unsigned long nr_deferred_pages;
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--- a/tools/libs/guest/xg_sr_save.c
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+++ b/tools/libs/guest/xg_sr_save.c
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@@ -96,7 +96,7 @@ static int write_batch(struct xc_sr_cont
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unsigned int nr_pfns = ctx->save.nr_batch_pfns;
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void *page, *orig_page;
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uint64_t *rec_pfns = NULL;
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- struct iovec *iov = NULL; int iovcnt = 0;
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+ int iovcnt = 0;
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struct xc_sr_rec_page_data_header hdr = { 0 };
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struct xc_sr_record rec = {
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.type = REC_TYPE_PAGE_DATA,
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@@ -108,10 +108,8 @@ static int write_batch(struct xc_sr_cont
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guest_data = calloc(nr_pfns, sizeof(*guest_data));
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/* Pointers to locally allocated pages. Need freeing. */
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local_pages = calloc(nr_pfns, sizeof(*local_pages));
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- /* iovec[] for writev(). */
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- iov = malloc((nr_pfns + 4) * sizeof(*iov));
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- if ( !guest_data || !local_pages || !iov )
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+ if ( !guest_data || !local_pages )
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{
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ERROR("Unable to allocate arrays for a batch of %u pages",
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nr_pfns);
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@@ -221,17 +219,17 @@ static int write_batch(struct xc_sr_cont
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for ( i = 0; i < nr_pfns; ++i )
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rec_pfns[i] = ((uint64_t)(ctx->save.types[i]) << 32) | ctx->save.batch_pfns[i];
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- iov[0].iov_base = &rec.type;
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- iov[0].iov_len = sizeof(rec.type);
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+ ctx->save.iov[0].iov_base = &rec.type;
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+ ctx->save.iov[0].iov_len = sizeof(rec.type);
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- iov[1].iov_base = &rec.length;
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- iov[1].iov_len = sizeof(rec.length);
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+ ctx->save.iov[1].iov_base = &rec.length;
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+ ctx->save.iov[1].iov_len = sizeof(rec.length);
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- iov[2].iov_base = &hdr;
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- iov[2].iov_len = sizeof(hdr);
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+ ctx->save.iov[2].iov_base = &hdr;
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+ ctx->save.iov[2].iov_len = sizeof(hdr);
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- iov[3].iov_base = rec_pfns;
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- iov[3].iov_len = nr_pfns * sizeof(*rec_pfns);
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+ ctx->save.iov[3].iov_base = rec_pfns;
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+ ctx->save.iov[3].iov_len = nr_pfns * sizeof(*rec_pfns);
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iovcnt = 4;
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ctx->save.pages_sent += nr_pages;
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@@ -243,15 +241,15 @@ static int write_batch(struct xc_sr_cont
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{
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if ( guest_data[i] )
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{
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- iov[iovcnt].iov_base = guest_data[i];
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- iov[iovcnt].iov_len = PAGE_SIZE;
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+ ctx->save.iov[iovcnt].iov_base = guest_data[i];
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+ ctx->save.iov[iovcnt].iov_len = PAGE_SIZE;
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iovcnt++;
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--nr_pages;
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}
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}
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}
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- if ( writev_exact(ctx->fd, iov, iovcnt) )
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+ if ( writev_exact(ctx->fd, ctx->save.iov, iovcnt) )
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{
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PERROR("Failed to write page data to stream");
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goto err;
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@@ -267,7 +265,6 @@ static int write_batch(struct xc_sr_cont
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xenforeignmemory_unmap(xch->fmem, guest_mapping, nr_pages_mapped);
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for ( i = 0; local_pages && i < nr_pfns; ++i )
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free(local_pages[i]);
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- free(iov);
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free(local_pages);
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free(guest_data);
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@@ -845,10 +842,12 @@ static int setup(struct xc_sr_context *c
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ctx->save.mfns = malloc(MAX_BATCH_SIZE * sizeof(*ctx->save.mfns));
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ctx->save.types = malloc(MAX_BATCH_SIZE * sizeof(*ctx->save.types));
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ctx->save.errors = malloc(MAX_BATCH_SIZE * sizeof(*ctx->save.errors));
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+ ctx->save.iov = malloc((4 + MAX_BATCH_SIZE) * sizeof(*ctx->save.iov));
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ctx->save.deferred_pages = bitmap_alloc(ctx->save.p2m_size);
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if ( !ctx->save.batch_pfns || !ctx->save.mfns || !ctx->save.types ||
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- !ctx->save.errors || !dirty_bitmap || !ctx->save.deferred_pages )
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+ !ctx->save.errors || !ctx->save.iov || !dirty_bitmap ||
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+ !ctx->save.deferred_pages )
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{
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ERROR("Unable to allocate memory for dirty bitmaps, batch pfns and"
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" deferred pages");
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@@ -879,6 +878,7 @@ static void cleanup(struct xc_sr_context
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xc_hypercall_buffer_free_pages(xch, dirty_bitmap,
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NRPAGES(bitmap_size(ctx->save.p2m_size)));
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free(ctx->save.deferred_pages);
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+ free(ctx->save.iov);
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free(ctx->save.errors);
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free(ctx->save.types);
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free(ctx->save.mfns);
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