59 lines
2.0 KiB
Diff
59 lines
2.0 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Stefan Reiter <s.reiter@proxmox.com>
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Date: Wed, 27 May 2020 11:33:21 +0200
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Subject: [PATCH] savevm-async: flush IOThread-drives async before entering
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blocking part
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By flushing all drives where its possible to so before entering the
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blocking part (where the VM is stopped), we can reduce the time spent in
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said part for every disk that has an IOThread (other drives cannot be
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flushed async anyway).
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Suggested-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
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---
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savevm-async.c | 23 +++++++++++++++++++++++
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1 file changed, 23 insertions(+)
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diff --git a/savevm-async.c b/savevm-async.c
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index 2894c94233..4ce83a0691 100644
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--- a/savevm-async.c
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+++ b/savevm-async.c
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@@ -253,6 +253,8 @@ static void coroutine_fn process_savevm_co(void *opaque)
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{
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int ret;
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int64_t maxlen;
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+ BdrvNextIterator it;
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+ BlockDriverState *bs = NULL;
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ret = qemu_file_get_error(snap_state.file);
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if (ret < 0) {
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@@ -288,6 +290,27 @@ static void coroutine_fn process_savevm_co(void *opaque)
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}
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}
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+ /* If a drive runs in an IOThread we can flush it async, and only
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+ * need to sync-flush whatever IO happens between now and
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+ * vm_stop_force_state. bdrv_next can only be called from main AioContext,
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+ * so move there now and after every flush.
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+ */
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+ aio_co_reschedule_self(qemu_get_aio_context());
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+ for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
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+ /* target has BDRV_O_NO_FLUSH, no sense calling bdrv_flush on it */
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+ if (bs == blk_bs(snap_state.target)) {
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+ continue;
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+ }
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+
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+ AioContext *bs_ctx = bdrv_get_aio_context(bs);
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+ if (bs_ctx != qemu_get_aio_context()) {
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+ DPRINTF("savevm: async flushing drive %s\n", bs->filename);
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+ aio_co_reschedule_self(bs_ctx);
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+ bdrv_flush(bs);
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+ aio_co_reschedule_self(qemu_get_aio_context());
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+ }
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+ }
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+
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qemu_bh_schedule(snap_state.finalize_bh);
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}
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