Re: [libvirt] [PATCH 1/3] qemu: Move memory limit computation to a reusable function

--- src/qemu/qemu_cgroup.c | 21 ++------------------- src/qemu/qemu_domain.c | 29 +++++++++++++++++++++++++++++ src/qemu/qemu_domain.h | 2 ++ 3 files changed, 33 insertions(+), 19 deletions(-) diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c index 5f54ca6..22bf78e 100644 --- a/src/qemu/qemu_cgroup.c +++ b/src/qemu/qemu_cgroup.c @@ -461,9 +461,7 @@ static int qemuSetupMemoryCgroup(virDomainObjPtr vm) { qemuDomainObjPrivatePtr priv = vm->privateData; - unsigned long long hard_limit; int rc; - int i; if (!virCgroupHasController(priv->cgroup,VIR_CGROUP_CONTROLLER_MEMORY)) { if (vm->def->mem.hard_limit != 0 || @@ -477,23 +475,8 @@ qemuSetupMemoryCgroup(virDomainObjPtr vm) } } - hard_limit = vm->def->mem.hard_limit; - if (!hard_limit) { - /* If there is no hard_limit set, set a reasonable one to avoid - * system thrashing caused by exploited qemu. A 'reasonable - * limit' has been chosen: - * (1 + k) * (domain memory + total video memory) + (32MB for - * cache per each disk) + F - * where k = 0.5 and F = 200MB. The cache for disks is important as - * kernel cache on the host side counts into the RSS limit. */ - hard_limit = vm->def->mem.max_balloon; - for (i = 0; i < vm->def->nvideos; i++) - hard_limit += vm->def->videos[i]->vram; - hard_limit = hard_limit * 1.5 + 204800; - hard_limit += vm->def->ndisks * 32768; - } - - rc = virCgroupSetMemoryHardLimit(priv->cgroup, hard_limit); + rc = virCgroupSetMemoryHardLimit(priv->cgroup, + qemuDomainMemoryLimit(vm->def)); if (rc != 0) { virReportSystemError(-rc, _("Unable to set memory hard limit for domain %s"), diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 8d79066..77b94ec 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -2181,3 +2181,32 @@ cleanup: virObjectUnref(cfg); return ret; } + + +unsigned long long +qemuDomainMemoryLimit(virDomainDefPtr def) +{ + unsigned long long mem; + int i; + + if (def->mem.hard_limit) { + mem = def->mem.hard_limit; + } else { + /* If there is no hard_limit set, compute a reasonable one to avoid + * system thrashing caused by exploited qemu. A 'reasonable + * limit' has been chosen: + * (1 + k) * (domain memory + total video memory) + (32MB for + * cache per each disk) + F + * where k = 0.5 and F = 200MB. The cache for disks is important as + * kernel cache on the host side counts into the RSS limit. + */ + mem = def->mem.max_balloon; + for (i = 0; i < def->nvideos; i++) + mem += def->videos[i]->vram; + mem *= 1.5; + mem += def->ndisks * 32768; + mem += 204800; + }

+ + return mem; +} diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h index 068a4c3..ade2095 100644 --- a/src/qemu/qemu_domain.h +++ b/src/qemu/qemu_domain.h @@ -351,4 +351,6 @@ extern virDomainXMLPrivateDataCallbacks virQEMUDriverPrivateDataCallbacks; extern virDomainXMLNamespace virQEMUDriverDomainXMLNamespace; extern virDomainDefParserConfig virQEMUDriverDomainDefParserConfig; +unsigned long long qemuDomainMemoryLimit(virDomainDefPtr def); + #endif /* __QEMU_DOMAIN_H__ */