4567474e95
Notable changes:
* bdrv_co_p{discard,readv,writev,write_zeroes} function signatures
changed, to using int64_t for offsets/bytes and some still had int
rather than BrdvRequestFlags for the flags.
* job_cancel_sync now has a force parameter. Commit messages in
73895f3838cd7fdaf185cf1dbc47be58844a966f
4cfb3f05627ad82af473e7f7ae113c3884cd04e3
sound like using force=true makes more sense.
* Added 3 patches coming in via qemu-stable tag, most important one is
to work around a librbd issue.
* Added another 3 patches from qemu-devel to fix issue leading to
crash when live migrating with iothread.
* cluster_size calculation helper changed (see patch pve/0026).
* QAPI's if conditionals now use 'CONFIG_FOO' rather than
'defined(CONFIG_FOO)'
Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
54 lines
1.6 KiB
Diff
54 lines
1.6 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, 9 Dec 2020 11:46:57 +0100
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Subject: [PATCH] PVE: block/pbs: fast-path reads without allocation if
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possible
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...and switch over to g_malloc/g_free while at it to align with other
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QEMU code.
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Tracing shows the fast-path is taken almost all the time, though not
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100% so the slow one is still necessary.
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Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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---
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block/pbs.c | 17 ++++++++++++++---
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1 file changed, 14 insertions(+), 3 deletions(-)
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diff --git a/block/pbs.c b/block/pbs.c
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index 0b05ea9080..c5eb4d5bad 100644
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--- a/block/pbs.c
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+++ b/block/pbs.c
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@@ -200,7 +200,16 @@ static coroutine_fn int pbs_co_preadv(BlockDriverState *bs,
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BDRVPBSState *s = bs->opaque;
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int ret;
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char *pbs_error = NULL;
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- uint8_t *buf = malloc(bytes);
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+ uint8_t *buf;
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+ bool inline_buf = true;
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+
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+ /* for single-buffer IO vectors we can fast-path the write directly to it */
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+ if (qiov->niov == 1 && qiov->iov->iov_len >= bytes) {
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+ buf = qiov->iov->iov_base;
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+ } else {
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+ inline_buf = false;
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+ buf = g_malloc(bytes);
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+ }
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if (offset < 0 || bytes < 0) {
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fprintf(stderr, "unexpected negative 'offset' or 'bytes' value!\n");
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@@ -223,8 +232,10 @@ static coroutine_fn int pbs_co_preadv(BlockDriverState *bs,
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return -EIO;
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}
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- qemu_iovec_from_buf(qiov, 0, buf, bytes);
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- free(buf);
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+ if (!inline_buf) {
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+ qemu_iovec_from_buf(qiov, 0, buf, bytes);
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+ g_free(buf);
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+ }
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return ret;
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}
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