[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH 81/81] thread-pool: add missing qemu_bh_cancel in co
From: |
Michael Roth |
Subject: |
[Qemu-devel] [PATCH 81/81] thread-pool: add missing qemu_bh_cancel in completion function |
Date: |
Mon, 20 Mar 2017 18:08:45 -0500 |
From: Peter Lieven <address@hidden>
commit 3c80ca15 fixed a deadlock scenarion with nested aio_poll invocations.
However, the rescheduling of the completion BH introcuded unnecessary spinning
in the main-loop. On very fast file backends this can even lead to the
"WARNING: I/O thread spun for 1000 iterations" message popping up.
Callgrind reports about 3-4% less instructions with this patch running
qemu-img bench on a ramdisk based VMDK file.
Fixes: 3c80ca158c96ff902a30883a8933e755988948b1
Cc: address@hidden
Signed-off-by: Peter Lieven <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
(cherry picked from commit b7a745dc33a18377bb4a8dfe54d1df01ea60bf66)
* drop context dep on b9e413d
Signed-off-by: Michael Roth <address@hidden>
---
thread-pool.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/thread-pool.c b/thread-pool.c
index 6fba913..4157210 100644
--- a/thread-pool.c
+++ b/thread-pool.c
@@ -185,6 +185,13 @@ restart:
qemu_bh_schedule(pool->completion_bh);
elem->common.cb(elem->common.opaque, elem->ret);
+
+ /* We can safely cancel the completion_bh here regardless of
someone
+ * else having scheduled it meanwhile because we reenter the
+ * completion function anyway (goto restart).
+ */
+ qemu_bh_cancel(pool->completion_bh);
+
qemu_aio_unref(elem);
goto restart;
} else {
--
2.7.4
- [Qemu-devel] [PATCH 08/81] 9pfs: local: llistxattr: don't follow symlinks, (continued)
- [Qemu-devel] [PATCH 08/81] 9pfs: local: llistxattr: don't follow symlinks, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 61/81] block/nfs: fix NULL pointer dereference in URI parsing, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 05/81] 9pfs: local: keep a file descriptor on the shared folder, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 64/81] vnc: do not disconnect on EAGAIN, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 63/81] sd: sdhci: check data length during dma_memory_read, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 76/81] NetRxPkt: Account buffer with ETH header in IOV length, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 66/81] block/vmdk: Fix the endian problem of buf_len and lba, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 73/81] eth: Extend vlan stripping functions, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 77/81] e1000e: correctly tear down MSI-X memory regions, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 78/81] scsi: mptsas: fix the wrong reading size in fetch request, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 81/81] thread-pool: add missing qemu_bh_cancel in completion function,
Michael Roth <=
- [Qemu-devel] [PATCH 71/81] hmp: fix block_set_io_throttle, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 72/81] cirrus: add blit_is_unsafe call to cirrus_bitblt_cputovideo (CVE-2017-2620), Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 80/81] s390x/css: reassign subchannel if schid is changed after migration, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 79/81] virtio-pci: reset modern vq meta data, Michael Roth, 2017/03/20
- [Qemu-devel] [PATCH 07/81] 9pfs: local: lgetxattr: don't follow symlinks, Michael Roth, 2017/03/20
- Re: [Qemu-devel] [PATCH 00/81] Patch Round-up for stable 2.8.1, freeze on 2017-03-27, Eric Blake, 2017/03/20
- Re: [Qemu-devel] [PATCH 00/81] Patch Round-up for stable 2.8.1, freeze on 2017-03-27, Richard Henderson, 2017/03/20
- Re: [Qemu-devel] [Qemu-stable] [PATCH 00/81] Patch Round-up for stable 2.8.1, freeze on 2017-03-27, Greg Kurz, 2017/03/21
- [Qemu-devel] [PATCH 55/81] s390x/kvm: fix cmma reset for KVM, Michael Roth, 2017/03/21