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[Qemu-stable] [PATCH 81/81] thread-pool: add missing qemu_bh_cancel in c
From: |
Michael Roth |
Subject: |
[Qemu-stable] [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-stable] [PATCH 04/81] 9pfs: introduce relative_openat_nofollow() helper, (continued)
- [Qemu-stable] [PATCH 04/81] 9pfs: introduce relative_openat_nofollow() helper, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 51/81] tcg/aarch64: Fix tcg_out_movi, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 60/81] s390x/kvm: fix small race reboot vs. cmma, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 56/81] cirrus: fix oob access issue (CVE-2017-2615), Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 58/81] ahci: advertise HOST_CAP_64, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 53/81] virtio: fix up max size checks, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 62/81] block/nfs: fix naming of runtime opts, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 67/81] target/sparc: Restore ldstub of odd asis, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 75/81] NetRxPkt: Do not try to pull more data than present, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 81/81] thread-pool: add missing qemu_bh_cancel in completion function,
Michael Roth <=
- [Qemu-stable] [PATCH 78/81] scsi: mptsas: fix the wrong reading size in fetch request, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 69/81] target-i386: correctly propagate retaddr into SVM helpers, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 71/81] hmp: fix block_set_io_throttle, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 72/81] cirrus: add blit_is_unsafe call to cirrus_bitblt_cputovideo (CVE-2017-2620), Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 61/81] block/nfs: fix NULL pointer dereference in URI parsing, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 08/81] 9pfs: local: llistxattr: don't follow symlinks, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 74/81] NetRxPkt: Fix memory corruption on VLAN header stripping, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 65/81] target-ppc, tcg: fix usermode segfault with pthread_create(), Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 05/81] 9pfs: local: keep a file descriptor on the shared folder, Michael Roth, 2017/03/20
- [Qemu-stable] [PATCH 63/81] sd: sdhci: check data length during dma_memory_read, Michael Roth, 2017/03/20