qemu-patch-raspberry4/include
Richard W.M. Jones 5c0919d020 virtio-scsi: Add virtqueue_size parameter allowing virtqueue size to be set.
Since Linux switched to blk-mq as the default in Linux commit
5c279bd9e406 ("scsi: default to scsi-mq"), virtio-scsi LUNs consume
about 10x as much guest kernel memory.

This commit allows you to choose the virtqueue size for each
virtio-scsi-pci controller like this:

  -device virtio-scsi-pci,id=scsi,virtqueue_size=16

The default is still 128 as before.  Using smaller virtqueue_size
allows many more disks to be added to small memory virtual machines.
For a 1 vCPU, 500 MB, no swap VM I observed:

  With scsi-mq enabled (upstream kernel):              175 disks
    -"- ditto -"-   virtqueue_size=64:                 318 disks
    -"- ditto -"-   virtqueue_size=16:                 775 disks
  With scsi-mq disabled (kernel before 5c279bd9e406): 1755 disks

Note that to have any effect, this requires a kernel patch:

  https://lkml.org/lkml/2017/8/10/689

Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Message-Id: <20170810165255.20865-1-rjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-09-19 14:09:11 +02:00
..
block nbd patches for 2017-09-06 2017-09-07 17:53:59 +01:00
chardev char: don't exit on hmp 'chardev-add help' 2017-08-01 17:27:33 +02:00
crypto crypto: hmac: add hmac driver framework 2017-07-19 10:11:05 +01:00
disas Fix Thumb-1 BE32 execution and disassembly. 2017-02-07 18:29:59 +00:00
exec tcg: Move USE_DIRECT_JUMP discriminator to tcg/cpu/tcg-target.h 2017-09-07 11:57:34 -07:00
fpu configure: Drop ancient Solaris 9 and earlier support 2017-07-21 15:04:05 +01:00
hw virtio-scsi: Add virtqueue_size parameter allowing virtqueue size to be set. 2017-09-19 14:09:11 +02:00
io io: Add new qio_channel_read{, v}_all_eof functions 2017-09-06 10:11:54 -05:00
libdecnumber Clean up ill-advised or unusual header guards 2016-07-12 16:20:46 +02:00
migration migration: remove check against colo support 2017-07-18 17:36:24 +02:00
monitor block: rip out all traces of password prompting 2017-07-11 17:44:56 +02:00
net net/net.c: Add vnet_hdr support in SocketReadState 2017-07-17 20:02:11 +08:00
qapi qapi: Change data type of the FOO_lookup generated for enum FOO 2017-09-04 13:09:13 +02:00
qemu hmp: extend "info numa" with hotplugged memory information 2017-09-14 15:52:10 +01:00
qom boards.h: Define new flag ignore_memory_transaction_failures 2017-09-07 13:54:54 +01:00
standard-headers linux-headers: update to 4.13-rc0 2017-07-14 12:29:10 +02:00
sysemu seccomp: add resourcecontrol argument to command line 2017-09-15 10:15:06 +02:00
ui console: use DIV_ROUND_UP 2017-08-31 12:29:07 +02:00
elf.h tcg/s390: Use constant pool for movi 2017-09-07 11:57:35 -07:00
glib-compat.h qga: Add 'guest-get-users' command 2017-04-26 23:57:45 -05:00
qemu-common.h maint: Include bug-reporting info in --help output 2017-08-08 17:28:53 +02:00
qemu-io.h hmp: Request permissions in qemu-io 2017-02-28 20:47:50 +01:00
trace-tcg.h trace: get rid of generated-events.h/generated-events.c 2016-10-12 09:54:52 +02:00