Re: [libvirt PATCH 1/2] conf: virtiofs: add thread_pool element

Add an element to configure the thread pool size: ... <binary> <thread_pool size='16'/> </binary> ... https://bugzilla.redhat.com/show_bug.cgi?id=2072905 Signed-off-by: Ján Tomko <jtomko(a)redhat.com&gt; --- docs/formatdomain.rst | 6 ++++++ src/conf/domain_conf.c | 14 ++++++++++++++ src/conf/domain_conf.h | 1 + src/conf/schemas/domaincommon.rng | 9 +++++++++ tests/qemuxml2argvdata/vhost-user-fs-fd-memory.xml | 1 + 5 files changed, 31 insertions(+) diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst index 7da625380c..e8bff7632a 100644 --- a/docs/formatdomain.rst +++ b/docs/formatdomain.rst @@ -3329,6 +3329,7 @@ A directory on the host that can be accessed directly from the guest. <cache mode='always'/> <sandbox mode='namespace'/> <lock posix='on' flock='on'/> + <thread_pool size='16'/>

</binary> <source dir='/path'/> <target dir='mount_tag'/> @@ -3462,6 +3463,11 @@ A directory on the host that can be accessed directly from the guest. ``chroot``, see the `virtiofsd documentation <https://qemu.readthedocs.io/en/latest/tools/virtiofsd.html>`__ for more details. ( :since:`Since 7.2.0` ) + Element ``thread_pool`` accepts one attribute ``size`` which defines the + maximum thread pool size. A value of "0" disables the pool. + The thread pool helps increase the number of requests in flight when used with + storage that has a higher latency. However, it has an overhead, and so for + fast, low latency filesystems, it may be best to turn it off. ( :since:`Since 8.5.0` ) ``source`` The resource on the host that is being accessed in the guest. The ``name`` attribute must be used with ``type='template'``, and the ``dir`` attribute diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 761c3f4d87..05fac7b39c 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -2476,6 +2476,8 @@ virDomainFSDefNew(virDomainXMLOption *xmlopt) ret->src = virStorageSourceNew(); + ret->thread_pool_size = -1; + if (xmlopt && xmlopt->privateData.fsNew && !(ret->privateData = xmlopt->privateData.fsNew())) @@ -9914,6 +9916,7 @@ virDomainFSDefParseXML(virDomainXMLOption *xmlopt, if (def->fsdriver == VIR_DOMAIN_FS_DRIVER_TYPE_VIRTIOFS) { g_autofree char *queue_size = virXPathString("string(./driver/@queue)", ctxt); g_autofree char *binary = virXPathString("string(./binary/@path)", ctxt); + g_autofree char *thread_pool_size = virXPathString("string(./binary/thread_pool/@size)", ctxt); xmlNodePtr binary_node = virXPathNode("./binary", ctxt); xmlNodePtr binary_lock_node = virXPathNode("./binary/lock", ctxt); xmlNodePtr binary_cache_node = virXPathNode("./binary/cache", ctxt); @@ -9926,6 +9929,13 @@ virDomainFSDefParseXML(virDomainXMLOption *xmlopt, goto error; } + if (thread_pool_size && virStrToLong_i(thread_pool_size, NULL, 10, &def->thread_pool_size) < 0) {

+ virReportError(VIR_ERR_XML_ERROR, + _("cannot parse thread pool size '%s' for virtiofs"), + queue_size); + goto error; + } + if (binary) def->binary = virFileSanitizePath(binary); @@ -24211,6 +24221,10 @@ virDomainFSDefFormat(virBuffer *buf, } virXMLFormatElement(&binaryBuf, "lock", &lockAttrBuf, NULL); + + if (def->thread_pool_size >= 0) + virBufferAsprintf(&binaryBuf, "<thread_pool size='%i'/>\n", def->thread_pool_size);

+ }