[libvirt] [PATCH] get memory in openvz driver
OpenVZ has several parameters for memory management. All of them can be configured independetly. Patch allow to get configuration of memory from container config and then calculate total usage of memory. It is open question how to manage memory?
On Wed, Aug 13, 2008 at 12:50:33PM +0400, Evgeniy Sokolov wrote:
OpenVZ has several parameters for memory management. All of them can be configured independetly.
Patch allow to get configuration of memory from container config and then calculate total usage of memory.
It is open question how to manage memory?
Basically the 'memory' as shown by libvirt should correspond to the 'Total' seen inside the guest when running 'free'. eg # free total used free shared buffers cached Mem: 524288 34676 489612 0 0 0 -/+ buffers/cache: 34676 489612 Swap: 0 0 0 In this case 'memory' is 524288 kb. This looks to correspond to OpenVZs 'PRIVVMPAGES' pages parameter.
+openvzFreeUbParam(struct openvz_ub_param *ub) +{ + if (ub == NULL) + return; +#define FREE_P(x) if (ub->x != NULL) VIR_FREE(ub->x);
This is not required. VIR_FREE is happy to accept a NULL and will do nothing. Just call VIR_FREE directly without testing for != NULL.
+/* calculate guaranteed memory for container +*/ +int +openvzUb2Memory(struct openvz_ub_param *ub, unsigned long *memory) +{ + unsigned long lowmem, mem, allmem; + + if (ub->oomguarpages == NULL || + ub->kmemsize == NULL || + ub->tcpsndbuf == NULL || + ub->tcprcvbuf == NULL || + ub->othersockbuf == NULL || + ub->dgramrcvbuf == NULL || + ub->lockedpages == NULL) + return -1; + + lowmem = ub->kmemsize->limit + + ub->tcpsndbuf->limit + + ub->tcprcvbuf->limit + + ub->othersockbuf->limit + + ub->dgramrcvbuf->limit + + ub->lockedpages->limit * get_pagesize(); + + mem = ub->oomguarpages->barrier * get_pagesize(); + allmem = mem + lowmem; //in bytes + *memory = allmem / 1024; //in kb
Summing all the different memory limits together is wrong - this will make it impossible to implement a 'setMemory' operation because you've now no way of deciding which parameter to set. In my testing the total memory inside a OpenVZ container seems to correspond to the 'lockedpages' parameter, so we should just return that value. Since you convert to 'bytes' before converting back into kb, you'll potentially overflow a 'long' on 32-bit platforms. You should use 'unsigned long long' instead to be safe.
+int +openvzUb2MaxMemory(struct openvz_ub_param *ub, unsigned long *memory) +{ + unsigned long lowmem, mem, allmem; + + if (ub->privvmpages == NULL || + ub->kmemsize == NULL || + ub->tcpsndbuf == NULL || + ub->tcprcvbuf == NULL || + ub->othersockbuf == NULL || + ub->dgramrcvbuf == NULL || + ub->lockedpages == NULL) + return -1; + + lowmem = ub->kmemsize->limit + + ub->tcpsndbuf->limit + + ub->tcprcvbuf->limit + + ub->othersockbuf->limit + + ub->dgramrcvbuf->limit + + ub->lockedpages->limit * get_pagesize(); + + mem = ub->privvmpages->barrier * get_pagesize(); + allmem = mem + lowmem; //in bytes + *memory = allmem / 1024; //in kb
Likewise this should simply use the lockedpages parameter I believe. What is the difference between a 'barrier' and a 'limit' in openvz config ? Would it make sense to map 'memory' to the 'barrier' and 'maxmemory' to the 'limit' ?
@@ -262,6 +264,10 @@ static int openvzDomainGetInfo(virDomain } }
+ openvzGetMemory(dom->conn, strtoI(dom->name), &(info->memory)) ; + openvzGetMaxMemory(dom->conn, strtoI(dom->name), &(info->maxMem)) ;
Can't you use 'vm->vpsid' and avoid the strtoI() call ? It seems it would be more efficient to call openvzReadUbParams() and openvzUb2Memory() & openvzUb2MaxMemory directly, rather than calling out to openvzGetMemory() and openvzGetMaxMemory() since it would avoid reading the config file twice - you can also get the nrVirtCPUs at the same time. Regards, Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|
On Wed, Aug 13, 2008 at 12:50:33PM +0400, Evgeniy Sokolov wrote:
OpenVZ has several parameters for memory management. All of them can be configured independetly.
Patch allow to get configuration of memory from container config and then calculate total usage of memory.
It is open question how to manage memory?
Basically the 'memory' as shown by libvirt should correspond to the 'Total' seen inside the guest when running 'free'.
eg
# free total used free shared buffers cached Mem: 524288 34676 489612 0 0 0 -/+ buffers/cache: 34676 489612 Swap: 0 0 0
In this case 'memory' is 524288 kb.
This looks to correspond to OpenVZs 'PRIVVMPAGES' pages parameter. It may be configured what will be shown in /proc/meminfo inside container. Memory from node, total memory or privvmpages. Privvmpages is default.
+openvzFreeUbParam(struct openvz_ub_param *ub) +{ + if (ub == NULL) + return; +#define FREE_P(x) if (ub->x != NULL) VIR_FREE(ub->x);
This is not required. VIR_FREE is happy to accept a NULL and will do nothing. Just call VIR_FREE directly without testing for != NULL.
+/* calculate guaranteed memory for container +*/ +int +openvzUb2Memory(struct openvz_ub_param *ub, unsigned long *memory) +{ + unsigned long lowmem, mem, allmem; + + if (ub->oomguarpages == NULL || + ub->kmemsize == NULL || + ub->tcpsndbuf == NULL || + ub->tcprcvbuf == NULL || + ub->othersockbuf == NULL || + ub->dgramrcvbuf == NULL || + ub->lockedpages == NULL) + return -1; + + lowmem = ub->kmemsize->limit + + ub->tcpsndbuf->limit + + ub->tcprcvbuf->limit + + ub->othersockbuf->limit + + ub->dgramrcvbuf->limit + + ub->lockedpages->limit * get_pagesize(); + + mem = ub->oomguarpages->barrier * get_pagesize(); + allmem = mem + lowmem; //in bytes + *memory = allmem / 1024; //in kb
Summing all the different memory limits together is wrong - this will make it impossible to implement a 'setMemory' operation because you've now no way of deciding which parameter to set. It is correct calcuation of total memory. Because of non-obvious implenetation of 'setMemory', I have asked 'how to manage memory' in begining. I propouse to set some portion of 'memory' to each limit.
In my testing the total memory inside a OpenVZ container seems to correspond to the 'lockedpages' parameter, so we should just return that value. How did you get total memory? Most big part of memory is oomguarpages (by default). Lockedpages is about %1.
Since you convert to 'bytes' before converting back into kb, you'll potentially overflow a 'long' on 32-bit platforms. You should use 'unsigned long long' instead to be safe. yes, you right.
+int +openvzUb2MaxMemory(struct openvz_ub_param *ub, unsigned long *memory) +{ + unsigned long lowmem, mem, allmem; + + if (ub->privvmpages == NULL || + ub->kmemsize == NULL || + ub->tcpsndbuf == NULL || + ub->tcprcvbuf == NULL || + ub->othersockbuf == NULL || + ub->dgramrcvbuf == NULL || + ub->lockedpages == NULL) + return -1; + + lowmem = ub->kmemsize->limit + + ub->tcpsndbuf->limit + + ub->tcprcvbuf->limit + + ub->othersockbuf->limit + + ub->dgramrcvbuf->limit + + ub->lockedpages->limit * get_pagesize(); + + mem = ub->privvmpages->barrier * get_pagesize(); + allmem = mem + lowmem; //in bytes + *memory = allmem / 1024; //in kb
Likewise this should simply use the lockedpages parameter I believe.
What is the difference between a 'barrier' and a 'limit' in openvz config ? Would it make sense to map 'memory' to the 'barrier' and 'maxmemory' to the 'limit' ? Barrier & limit are soft and hard limits. Barrier is guarantee availability of resources. When resource is grown up to barrier, it can grow more resurce within grace period, but not more than limit.
Memory for application: oomguarpages & vmguarpages - barrier has matter. It is guarantee number of pages. Limits should be always very big - 2147483647. When the whole node is in out of memory, kernel may don't allow to allocate memory or kill container process. Container may allocate more memory if memory on whole node is available, but no more than privvmpages.
@@ -262,6 +264,10 @@ static int openvzDomainGetInfo(virDomain } }
+ openvzGetMemory(dom->conn, strtoI(dom->name), &(info->memory)) ; + openvzGetMaxMemory(dom->conn, strtoI(dom->name), &(info->maxMem)) ;
Can't you use 'vm->vpsid' and avoid the strtoI() call ?
vm->vpsid = -1 when VM is stoped.
It seems it would be more efficient to call openvzReadUbParams() and openvzUb2Memory() & openvzUb2MaxMemory directly, rather than calling out to openvzGetMemory() and openvzGetMaxMemory() since it would avoid reading the config file twice - you can also get the nrVirtCPUs at the same time.
Yes, we can read memory once. But get number of CPUs is little complicated.
Regards, Daniel
On Thu, Aug 14, 2008 at 06:08:31PM +0400, Evgeniy Sokolov wrote:
On Wed, Aug 13, 2008 at 12:50:33PM +0400, Evgeniy Sokolov wrote:
OpenVZ has several parameters for memory management. All of them can be configured independetly.
Summing all the different memory limits together is wrong - this will make it impossible to implement a 'setMemory' operation because you've now no way of deciding which parameter to set. It is correct calcuation of total memory. Because of non-obvious implenetation of 'setMemory', I have asked 'how to manage memory' in begining. I propouse to set some portion of 'memory' to each limit.
I don't think that will be lead to good behaviour - ultimtely I think we'll need to expose more (all?) of these memory settings directly as tunable resources. THus for the 'memory' setting we which pick the value which provides the primary memory size as available to apps within the container.
In my testing the total memory inside a OpenVZ container seems to correspond to the 'lockedpages' parameter, so we should just return that value.
How did you get total memory? Most big part of memory is oomguarpages (by default). Lockedpages is about %1.
I've just found & read these descriptions... http://wiki.openvz.org/Oomguarpages#oomguarpages http://wiki.openvz.org/Oomguarpages#privvmpages http://wiki.openvz.org/Vmguarpages#vmguarpages To summarize "Oomguarpages parameter accounts the total amount of memory and swap space used by the processes of a particular container. "Privvmpages parameter accounts allocated (but, possibly, not used yet) memory. The accounted value is an estimation how much memory will be really consumed when the container's applications start to use the allocated memory. Consumed memory is accounted into oomguarpages parameter "vmguarpages parameter controls how much memory is available to the Virtual Environment (i.e. how much memory its applications can allocate by malloc(3) or other standard Linux memory allocation mechanisms" "The memory allocation guarantee (vmguarpages) is a primary tool for controlling the memory available to containers, because it allows administrators to provide Service Level Agreements" So from those I'd think that 'vmguarpages' maps best into libvirt's concept of 'memory'. Though perhaps 'oomguardpages' could be set for 'memory' and 'vmguarpages' used for 'max memory' Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|
On Thu, Aug 14, 2008 at 06:08:31PM +0400, Evgeniy Sokolov wrote:
On Wed, Aug 13, 2008 at 12:50:33PM +0400, Evgeniy Sokolov wrote:
OpenVZ has several parameters for memory management. All of them can be configured independetly. Summing all the different memory limits together is wrong - this will make it impossible to implement a 'setMemory' operation because you've now no way of deciding which parameter to set. It is correct calcuation of total memory. Because of non-obvious implenetation of 'setMemory', I have asked 'how to manage memory' in begining. I propouse to set some portion of 'memory' to each limit.
I don't think that will be lead to good behaviour - ultimtely I think we'll need to expose more (all?) of these memory settings directly as tunable resources. Good idea! 5 setting for low memory + application THus for the 'memory' setting we which pick the value which provides the primary memory size as available to apps within the container.
In my testing the total memory inside a OpenVZ container seems to correspond to the 'lockedpages' parameter, so we should just return that value. How did you get total memory? Most big part of memory is oomguarpages (by default). Lockedpages is about %1.
I've just found & read these descriptions...
http://wiki.openvz.org/Oomguarpages#oomguarpages http://wiki.openvz.org/Oomguarpages#privvmpages http://wiki.openvz.org/Vmguarpages#vmguarpages
To summarize
"Oomguarpages parameter accounts the total amount of memory and swap space used by the processes of a particular container.
"Privvmpages parameter accounts allocated (but, possibly, not used yet) memory. The accounted value is an estimation how much memory will be really consumed when the container's applications start to use the allocated memory. Consumed memory is accounted into oomguarpages parameter
"vmguarpages parameter controls how much memory is available to the Virtual Environment (i.e. how much memory its applications can allocate by malloc(3) or other standard Linux memory allocation mechanisms"
"The memory allocation guarantee (vmguarpages) is a primary tool for controlling the memory available to containers, because it allows administrators to provide Service Level Agreements"
So from those I'd think that 'vmguarpages' maps best into libvirt's concept of 'memory'. Though perhaps 'oomguardpages' could be set for 'memory' and 'vmguarpages' used for 'max memory' Oomguarpages & Privvmpages & vmguarpages are settings for apps memory.
We may 1 set 'memory' to 'privvmpages' - then free will show correct value. 2 set 'memory' to 'vmguarpages' or 'oomguardpages' and 'maxmemory' to 'privvmpages'. What do 'MaxMemory' mean for other libvirt drivers? Bad point of it, for example: We can set many of Oomguarpages & Privvmpages & vmguarpages but application can not start because of 'kmemsize' is over.
Daniel
participants (2)
-
Daniel P. Berrange -
Evgeniy Sokolov