qemu-kvm/kvm-block-skip-automatic-zero-init-of-large-array-in-ioq.patch
Miroslav Rezanina 0dde13a5cd * Mon Jul 07 2025 Miroslav Rezanina <mrezanin@redhat.com> - 10.0.0-7
- kvm-s390x-Fix-leak-in-machine_set_loadparm.patch [RHEL-98555]
- kvm-hw-s390x-ccw-device-Fix-memory-leak-in-loadparm-sett.patch [RHEL-98555]
- kvm-target-i386-Update-EPYC-CPU-model-for-Cache-property.patch [RHEL-52650]
- kvm-target-i386-Update-EPYC-Rome-CPU-model-for-Cache-pro.patch [RHEL-52650]
- kvm-target-i386-Update-EPYC-Milan-CPU-model-for-Cache-pr.patch [RHEL-52650]
- kvm-target-i386-Add-couple-of-feature-bits-in-CPUID_Fn80.patch [RHEL-52650]
- kvm-target-i386-Update-EPYC-Genoa-for-Cache-property-per.patch [RHEL-52650]
- kvm-target-i386-Add-support-for-EPYC-Turin-model.patch [RHEL-52650]
- kvm-include-qemu-compiler-add-QEMU_UNINITIALIZED-attribu.patch [RHEL-95479]
- kvm-hw-virtio-virtio-avoid-cost-of-ftrivial-auto-var-ini.patch [RHEL-95479]
- kvm-block-skip-automatic-zero-init-of-large-array-in-ioq.patch [RHEL-95479]
- kvm-chardev-char-fd-skip-automatic-zero-init-of-large-ar.patch [RHEL-95479]
- kvm-chardev-char-pty-skip-automatic-zero-init-of-large-a.patch [RHEL-95479]
- kvm-chardev-char-socket-skip-automatic-zero-init-of-larg.patch [RHEL-95479]
- kvm-hw-audio-ac97-skip-automatic-zero-init-of-large-arra.patch [RHEL-95479]
- kvm-hw-audio-cs4231a-skip-automatic-zero-init-of-large-a.patch [RHEL-95479]
- kvm-hw-audio-es1370-skip-automatic-zero-init-of-large-ar.patch [RHEL-95479]
- kvm-hw-audio-gus-skip-automatic-zero-init-of-large-array.patch [RHEL-95479]
- kvm-hw-audio-marvell_88w8618-skip-automatic-zero-init-of.patch [RHEL-95479]
- kvm-hw-audio-sb16-skip-automatic-zero-init-of-large-arra.patch [RHEL-95479]
- kvm-hw-audio-via-ac97-skip-automatic-zero-init-of-large-.patch [RHEL-95479]
- kvm-hw-char-sclpconsole-lm-skip-automatic-zero-init-of-l.patch [RHEL-95479]
- kvm-hw-dma-xlnx_csu_dma-skip-automatic-zero-init-of-larg.patch [RHEL-95479]
- kvm-hw-display-vmware_vga-skip-automatic-zero-init-of-la.patch [RHEL-95479]
- kvm-hw-hyperv-syndbg-skip-automatic-zero-init-of-large-a.patch [RHEL-95479]
- kvm-hw-misc-aspeed_hace-skip-automatic-zero-init-of-larg.patch [RHEL-95479]
- kvm-hw-net-rtl8139-skip-automatic-zero-init-of-large-arr.patch [RHEL-95479]
- kvm-hw-net-tulip-skip-automatic-zero-init-of-large-array.patch [RHEL-95479]
- kvm-hw-net-virtio-net-skip-automatic-zero-init-of-large-.patch [RHEL-95479]
- kvm-hw-net-xgamc-skip-automatic-zero-init-of-large-array.patch [RHEL-95479]
- kvm-hw-nvme-ctrl-skip-automatic-zero-init-of-large-array.patch [RHEL-95479]
- kvm-hw-ppc-pnv_occ-skip-automatic-zero-init-of-large-str.patch [RHEL-95479]
- kvm-hw-ppc-spapr_tpm_proxy-skip-automatic-zero-init-of-l.patch [RHEL-95479]
- kvm-hw-usb-hcd-ohci-skip-automatic-zero-init-of-large-ar.patch [RHEL-95479]
- kvm-hw-scsi-lsi53c895a-skip-automatic-zero-init-of-large.patch [RHEL-95479]
- kvm-hw-scsi-megasas-skip-automatic-zero-init-of-large-ar.patch [RHEL-95479]
- kvm-hw-ufs-lu-skip-automatic-zero-init-of-large-array.patch [RHEL-95479]
- kvm-net-socket-skip-automatic-zero-init-of-large-array.patch [RHEL-95479]
- kvm-net-stream-skip-automatic-zero-init-of-large-array.patch [RHEL-95479]
- kvm-hw-i386-amd_iommu-Isolate-AMDVI-PCI-from-amd-iommu-d.patch [RHEL-85649]
- kvm-hw-i386-amd_iommu-Allow-migration-when-explicitly-cr.patch [RHEL-85649]
- kvm-Enable-amd-iommu-device.patch [RHEL-85649]
- kvm-ui-vnc-Update-display-update-interval-when-VM-state-.patch [RHEL-83883]
- Resolves: RHEL-98555
  ([s390x][RHEL10.1][ccw-device] there would be memory leak with virtio_blk disks)
- Resolves: RHEL-52650
  ([AMDSERVER 10.1 Feature] Turin: Qemu EPYC-Turin Model)
- Resolves: RHEL-95479
  (-ftrivial-auto-var-init=zero reduced performance)
- Resolves: RHEL-85649
  ([RHEL 10]Qemu/amd-iommu: Add ability to manually specify the AMDVI-PCI device)
- Resolves: RHEL-83883
  (Video stuck after switchover phase when play one video during migration)
2025-07-07 03:44:31 -04:00

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1.7 KiB
Diff

From 116f42add040dfa1eaf25087db1038f8c4198bf7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= <berrange@redhat.com>
Date: Tue, 10 Jun 2025 13:36:41 +0100
Subject: [PATCH 11/43] block: skip automatic zero-init of large array in
ioq_submit
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Stefan Hajnoczi <stefanha@redhat.com>
RH-MergeRequest: 381: Solve -ftrivial-auto-var-init performance regression with QEMU_UNINITIALIZED
RH-Jira: RHEL-95479
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Commit: [3/31] 3d4c81fcc56f1c7a4d1d3819214bd6296edc2a1e (stefanha/centos-stream-qemu-kvm)
The 'ioq_submit' method has a struct array that is 8k in size.
Skip the automatic zero-init of this array to eliminate the
performance overhead in the I/O hot path.
The 'iocbs' array will selectively initialized when processing
the I/O data.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20250610123709.835102-4-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 83750c1da807c973b0b11d977d61df7e41122d03)
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
block/linux-aio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/linux-aio.c b/block/linux-aio.c
index 407369f5c9..c200e7ad20 100644
--- a/block/linux-aio.c
+++ b/block/linux-aio.c
@@ -291,7 +291,7 @@ static void ioq_submit(LinuxAioState *s)
{
int ret, len;
struct qemu_laiocb *aiocb;
- struct iocb *iocbs[MAX_EVENTS];
+ QEMU_UNINITIALIZED struct iocb *iocbs[MAX_EVENTS];
QSIMPLEQ_HEAD(, qemu_laiocb) completed;
do {
--
2.39.3