pve-qemu-qoup/debian/patches/pve/0043-PVE-block-pbs-fast-path-reads-without-allocation-if-.patch
Wolfgang Bumiller 277d33454f drop patch force-disabling smm
This drops debian/patches/pve/0005-PVE-Config-smm_available-false.patch
(and renumbers the remaining patches)

From what I could gather, this patch was originally added
due to issues with old kernels. Now we have users which
seem to run into issues *with* the patch.

All this does is toggle an option, and it's available via a
qemu CLI option anyway, so if dropping this patch causes
issues for some people we can just add an option to
qemu-server & UI control smm explicitly.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Cc: Alexandre Derumier <aderumier@odiso.com>
Tested-by: Stefan Reiter <s.reiter@proxmox.com>
2021-08-24 11:19:05 +02:00

53 lines
1.5 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Stefan Reiter <s.reiter@proxmox.com>
Date: Wed, 9 Dec 2020 11:46:57 +0100
Subject: [PATCH] PVE: block/pbs: fast-path reads without allocation if
possible
...and switch over to g_malloc/g_free while at it to align with other
QEMU code.
Tracing shows the fast-path is taken almost all the time, though not
100% so the slow one is still necessary.
Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
---
block/pbs.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/block/pbs.c b/block/pbs.c
index 78dad0dcc4..ac54e816c0 100644
--- a/block/pbs.c
+++ b/block/pbs.c
@@ -200,7 +200,16 @@ static coroutine_fn int pbs_co_preadv(BlockDriverState *bs,
BDRVPBSState *s = bs->opaque;
int ret;
char *pbs_error = NULL;
- uint8_t *buf = malloc(bytes);
+ uint8_t *buf;
+ bool inline_buf = true;
+
+ /* for single-buffer IO vectors we can fast-path the write directly to it */
+ if (qiov->niov == 1 && qiov->iov->iov_len >= bytes) {
+ buf = qiov->iov->iov_base;
+ } else {
+ inline_buf = false;
+ buf = g_malloc(bytes);
+ }
ReadCallbackData rcb = {
.co = qemu_coroutine_self(),
@@ -218,8 +227,10 @@ static coroutine_fn int pbs_co_preadv(BlockDriverState *bs,
return -EIO;
}
- qemu_iovec_from_buf(qiov, 0, buf, bytes);
- free(buf);
+ if (!inline_buf) {
+ qemu_iovec_from_buf(qiov, 0, buf, bytes);
+ g_free(buf);
+ }
return ret;
}