linux/net/openvswitch/flow.h

286 lines
8.1 KiB

openvswitch: Add original direction conntrack tuple to sw_flow_key. Add the fields of the conntrack original direction 5-tuple to struct sw_flow_key. The new fields are initially marked as non-existent, and are populated whenever a conntrack action is executed and either finds or generates a conntrack entry. This means that these fields exist for all packets that were not rejected by conntrack as untrackable. The original tuple fields in the sw_flow_key are filled from the original direction tuple of the conntrack entry relating to the current packet, or from the original direction tuple of the master conntrack entry, if the current conntrack entry has a master. Generally, expected connections of connections having an assigned helper (e.g., FTP), have a master conntrack entry. The main purpose of the new conntrack original tuple fields is to allow matching on them for policy decision purposes, with the premise that the admissibility of tracked connections reply packets (as well as original direction packets), and both direction packets of any related connections may be based on ACL rules applying to the master connection's original direction 5-tuple. This also makes it easier to make policy decisions when the actual packet headers might have been transformed by NAT, as the original direction 5-tuple represents the packet headers before any such transformation. When using the original direction 5-tuple the admissibility of return and/or related packets need not be based on the mere existence of a conntrack entry, allowing separation of admission policy from the established conntrack state. While existence of a conntrack entry is required for admission of the return or related packets, policy changes can render connections that were initially admitted to be rejected or dropped afterwards. If the admission of the return and related packets was based on mere conntrack state (e.g., connection being in an established state), a policy change that would make the connection rejected or dropped would need to find and delete all conntrack entries affected by such a change. When using the original direction 5-tuple matching the affected conntrack entries can be allowed to time out instead, as the established state of the connection would not need to be the basis for packet admission any more. It should be noted that the directionality of related connections may be the same or different than that of the master connection, and neither the original direction 5-tuple nor the conntrack state bits carry this information. If needed, the directionality of the master connection can be stored in master's conntrack mark or labels, which are automatically inherited by the expected related connections. The fact that neither ARP nor ND packets are trackable by conntrack allows mutual exclusion between ARP/ND and the new conntrack original tuple fields. Hence, the IP addresses are overlaid in union with ARP and ND fields. This allows the sw_flow_key to not grow much due to this patch, but it also means that we must be careful to never use the new key fields with ARP or ND packets. ARP is easy to distinguish and keep mutually exclusive based on the ethernet type, but ND being an ICMPv6 protocol requires a bit more attention. Signed-off-by: Jarno Rajahalme <jarno@ovn.org> Acked-by: Joe Stringer <joe@ovn.org> Acked-by: Pravin B Shelar <pshelar@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-09 11:21:59 -08:00
openvswitch: Add original direction conntrack tuple to sw_flow_key. Add the fields of the conntrack original direction 5-tuple to struct sw_flow_key. The new fields are initially marked as non-existent, and are populated whenever a conntrack action is executed and either finds or generates a conntrack entry. This means that these fields exist for all packets that were not rejected by conntrack as untrackable. The original tuple fields in the sw_flow_key are filled from the original direction tuple of the conntrack entry relating to the current packet, or from the original direction tuple of the master conntrack entry, if the current conntrack entry has a master. Generally, expected connections of connections having an assigned helper (e.g., FTP), have a master conntrack entry. The main purpose of the new conntrack original tuple fields is to allow matching on them for policy decision purposes, with the premise that the admissibility of tracked connections reply packets (as well as original direction packets), and both direction packets of any related connections may be based on ACL rules applying to the master connection's original direction 5-tuple. This also makes it easier to make policy decisions when the actual packet headers might have been transformed by NAT, as the original direction 5-tuple represents the packet headers before any such transformation. When using the original direction 5-tuple the admissibility of return and/or related packets need not be based on the mere existence of a conntrack entry, allowing separation of admission policy from the established conntrack state. While existence of a conntrack entry is required for admission of the return or related packets, policy changes can render connections that were initially admitted to be rejected or dropped afterwards. If the admission of the return and related packets was based on mere conntrack state (e.g., connection being in an established state), a policy change that would make the connection rejected or dropped would need to find and delete all conntrack entries affected by such a change. When using the original direction 5-tuple matching the affected conntrack entries can be allowed to time out instead, as the established state of the connection would not need to be the basis for packet admission any more. It should be noted that the directionality of related connections may be the same or different than that of the master connection, and neither the original direction 5-tuple nor the conntrack state bits carry this information. If needed, the directionality of the master connection can be stored in master's conntrack mark or labels, which are automatically inherited by the expected related connections. The fact that neither ARP nor ND packets are trackable by conntrack allows mutual exclusion between ARP/ND and the new conntrack original tuple fields. Hence, the IP addresses are overlaid in union with ARP and ND fields. This allows the sw_flow_key to not grow much due to this patch, but it also means that we must be careful to never use the new key fields with ARP or ND packets. ARP is easy to distinguish and keep mutually exclusive based on the ethernet type, but ND being an ICMPv6 protocol requires a bit more attention. Signed-off-by: Jarno Rajahalme <jarno@ovn.org> Acked-by: Joe Stringer <joe@ovn.org> Acked-by: Pravin B Shelar <pshelar@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-09 11:21:59 -08:00
openvswitch: Add original direction conntrack tuple to sw_flow_key. Add the fields of the conntrack original direction 5-tuple to struct sw_flow_key. The new fields are initially marked as non-existent, and are populated whenever a conntrack action is executed and either finds or generates a conntrack entry. This means that these fields exist for all packets that were not rejected by conntrack as untrackable. The original tuple fields in the sw_flow_key are filled from the original direction tuple of the conntrack entry relating to the current packet, or from the original direction tuple of the master conntrack entry, if the current conntrack entry has a master. Generally, expected connections of connections having an assigned helper (e.g., FTP), have a master conntrack entry. The main purpose of the new conntrack original tuple fields is to allow matching on them for policy decision purposes, with the premise that the admissibility of tracked connections reply packets (as well as original direction packets), and both direction packets of any related connections may be based on ACL rules applying to the master connection's original direction 5-tuple. This also makes it easier to make policy decisions when the actual packet headers might have been transformed by NAT, as the original direction 5-tuple represents the packet headers before any such transformation. When using the original direction 5-tuple the admissibility of return and/or related packets need not be based on the mere existence of a conntrack entry, allowing separation of admission policy from the established conntrack state. While existence of a conntrack entry is required for admission of the return or related packets, policy changes can render connections that were initially admitted to be rejected or dropped afterwards. If the admission of the return and related packets was based on mere conntrack state (e.g., connection being in an established state), a policy change that would make the connection rejected or dropped would need to find and delete all conntrack entries affected by such a change. When using the original direction 5-tuple matching the affected conntrack entries can be allowed to time out instead, as the established state of the connection would not need to be the basis for packet admission any more. It should be noted that the directionality of related connections may be the same or different than that of the master connection, and neither the original direction 5-tuple nor the conntrack state bits carry this information. If needed, the directionality of the master connection can be stored in master's conntrack mark or labels, which are automatically inherited by the expected related connections. The fact that neither ARP nor ND packets are trackable by conntrack allows mutual exclusion between ARP/ND and the new conntrack original tuple fields. Hence, the IP addresses are overlaid in union with ARP and ND fields. This allows the sw_flow_key to not grow much due to this patch, but it also means that we must be careful to never use the new key fields with ARP or ND packets. ARP is easy to distinguish and keep mutually exclusive based on the ethernet type, but ND being an ICMPv6 protocol requires a bit more attention. Signed-off-by: Jarno Rajahalme <jarno@ovn.org> Acked-by: Joe Stringer <joe@ovn.org> Acked-by: Pravin B Shelar <pshelar@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-09 11:21:59 -08:00
openvswitch: Add conntrack action Expose the kernel connection tracker via OVS. Userspace components can make use of the CT action to populate the connection state (ct_state) field for a flow. This state can be subsequently matched. Exposed connection states are OVS_CS_F_*: - NEW (0x01) - Beginning of a new connection. - ESTABLISHED (0x02) - Part of an existing connection. - RELATED (0x04) - Related to an established connection. - INVALID (0x20) - Could not track the connection for this packet. - REPLY_DIR (0x40) - This packet is in the reply direction for the flow. - TRACKED (0x80) - This packet has been sent through conntrack. When the CT action is executed by itself, it will send the packet through the connection tracker and populate the ct_state field with one or more of the connection state flags above. The CT action will always set the TRACKED bit. When the COMMIT flag is passed to the conntrack action, this specifies that information about the connection should be stored. This allows subsequent packets for the same (or related) connections to be correlated with this connection. Sending subsequent packets for the connection through conntrack allows the connection tracker to consider the packets as ESTABLISHED, RELATED, and/or REPLY_DIR. The CT action may optionally take a zone to track the flow within. This allows connections with the same 5-tuple to be kept logically separate from connections in other zones. If the zone is specified, then the "ct_zone" match field will be subsequently populated with the zone id. IP fragments are handled by transparently assembling them as part of the CT action. The maximum received unit (MRU) size is tracked so that refragmentation can occur during output. IP frag handling contributed by Andy Zhou. Based on original design by Justin Pettit. Signed-off-by: Joe Stringer <joestringer@nicira.com> Signed-off-by: Justin Pettit <jpettit@nicira.com> Signed-off-by: Andy Zhou <azhou@nicira.com> Acked-by: Thomas Graf <tgraf@suug.ch> Acked-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-26 11:31:48 -07:00
openvswitch: Add original direction conntrack tuple to sw_flow_key. Add the fields of the conntrack original direction 5-tuple to struct sw_flow_key. The new fields are initially marked as non-existent, and are populated whenever a conntrack action is executed and either finds or generates a conntrack entry. This means that these fields exist for all packets that were not rejected by conntrack as untrackable. The original tuple fields in the sw_flow_key are filled from the original direction tuple of the conntrack entry relating to the current packet, or from the original direction tuple of the master conntrack entry, if the current conntrack entry has a master. Generally, expected connections of connections having an assigned helper (e.g., FTP), have a master conntrack entry. The main purpose of the new conntrack original tuple fields is to allow matching on them for policy decision purposes, with the premise that the admissibility of tracked connections reply packets (as well as original direction packets), and both direction packets of any related connections may be based on ACL rules applying to the master connection's original direction 5-tuple. This also makes it easier to make policy decisions when the actual packet headers might have been transformed by NAT, as the original direction 5-tuple represents the packet headers before any such transformation. When using the original direction 5-tuple the admissibility of return and/or related packets need not be based on the mere existence of a conntrack entry, allowing separation of admission policy from the established conntrack state. While existence of a conntrack entry is required for admission of the return or related packets, policy changes can render connections that were initially admitted to be rejected or dropped afterwards. If the admission of the return and related packets was based on mere conntrack state (e.g., connection being in an established state), a policy change that would make the connection rejected or dropped would need to find and delete all conntrack entries affected by such a change. When using the original direction 5-tuple matching the affected conntrack entries can be allowed to time out instead, as the established state of the connection would not need to be the basis for packet admission any more. It should be noted that the directionality of related connections may be the same or different than that of the master connection, and neither the original direction 5-tuple nor the conntrack state bits carry this information. If needed, the directionality of the master connection can be stored in master's conntrack mark or labels, which are automatically inherited by the expected related connections. The fact that neither ARP nor ND packets are trackable by conntrack allows mutual exclusion between ARP/ND and the new conntrack original tuple fields. Hence, the IP addresses are overlaid in union with ARP and ND fields. This allows the sw_flow_key to not grow much due to this patch, but it also means that we must be careful to never use the new key fields with ARP or ND packets. ARP is easy to distinguish and keep mutually exclusive based on the ethernet type, but ND being an ICMPv6 protocol requires a bit more attention. Signed-off-by: Jarno Rajahalme <jarno@ovn.org> Acked-by: Joe Stringer <joe@ovn.org> Acked-by: Pravin B Shelar <pshelar@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-09 11:21:59 -08:00
openvswitch: Add conntrack action Expose the kernel connection tracker via OVS. Userspace components can make use of the CT action to populate the connection state (ct_state) field for a flow. This state can be subsequently matched. Exposed connection states are OVS_CS_F_*: - NEW (0x01) - Beginning of a new connection. - ESTABLISHED (0x02) - Part of an existing connection. - RELATED (0x04) - Related to an established connection. - INVALID (0x20) - Could not track the connection for this packet. - REPLY_DIR (0x40) - This packet is in the reply direction for the flow. - TRACKED (0x80) - This packet has been sent through conntrack. When the CT action is executed by itself, it will send the packet through the connection tracker and populate the ct_state field with one or more of the connection state flags above. The CT action will always set the TRACKED bit. When the COMMIT flag is passed to the conntrack action, this specifies that information about the connection should be stored. This allows subsequent packets for the same (or related) connections to be correlated with this connection. Sending subsequent packets for the connection through conntrack allows the connection tracker to consider the packets as ESTABLISHED, RELATED, and/or REPLY_DIR. The CT action may optionally take a zone to track the flow within. This allows connections with the same 5-tuple to be kept logically separate from connections in other zones. If the zone is specified, then the "ct_zone" match field will be subsequently populated with the zone id. IP fragments are handled by transparently assembling them as part of the CT action. The maximum received unit (MRU) size is tracked so that refragmentation can occur during output. IP frag handling contributed by Andy Zhou. Based on original design by Justin Pettit. Signed-off-by: Joe Stringer <joestringer@nicira.com> Signed-off-by: Justin Pettit <jpettit@nicira.com> Signed-off-by: Andy Zhou <azhou@nicira.com> Acked-by: Thomas Graf <tgraf@suug.ch> Acked-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-26 11:31:48 -07:00
openvswitch: Add original direction conntrack tuple to sw_flow_key. Add the fields of the conntrack original direction 5-tuple to struct sw_flow_key. The new fields are initially marked as non-existent, and are populated whenever a conntrack action is executed and either finds or generates a conntrack entry. This means that these fields exist for all packets that were not rejected by conntrack as untrackable. The original tuple fields in the sw_flow_key are filled from the original direction tuple of the conntrack entry relating to the current packet, or from the original direction tuple of the master conntrack entry, if the current conntrack entry has a master. Generally, expected connections of connections having an assigned helper (e.g., FTP), have a master conntrack entry. The main purpose of the new conntrack original tuple fields is to allow matching on them for policy decision purposes, with the premise that the admissibility of tracked connections reply packets (as well as original direction packets), and both direction packets of any related connections may be based on ACL rules applying to the master connection's original direction 5-tuple. This also makes it easier to make policy decisions when the actual packet headers might have been transformed by NAT, as the original direction 5-tuple represents the packet headers before any such transformation. When using the original direction 5-tuple the admissibility of return and/or related packets need not be based on the mere existence of a conntrack entry, allowing separation of admission policy from the established conntrack state. While existence of a conntrack entry is required for admission of the return or related packets, policy changes can render connections that were initially admitted to be rejected or dropped afterwards. If the admission of the return and related packets was based on mere conntrack state (e.g., connection being in an established state), a policy change that would make the connection rejected or dropped would need to find and delete all conntrack entries affected by such a change. When using the original direction 5-tuple matching the affected conntrack entries can be allowed to time out instead, as the established state of the connection would not need to be the basis for packet admission any more. It should be noted that the directionality of related connections may be the same or different than that of the master connection, and neither the original direction 5-tuple nor the conntrack state bits carry this information. If needed, the directionality of the master connection can be stored in master's conntrack mark or labels, which are automatically inherited by the expected related connections. The fact that neither ARP nor ND packets are trackable by conntrack allows mutual exclusion between ARP/ND and the new conntrack original tuple fields. Hence, the IP addresses are overlaid in union with ARP and ND fields. This allows the sw_flow_key to not grow much due to this patch, but it also means that we must be careful to never use the new key fields with ARP or ND packets. ARP is easy to distinguish and keep mutually exclusive based on the ethernet type, but ND being an ICMPv6 protocol requires a bit more attention. Signed-off-by: Jarno Rajahalme <jarno@ovn.org> Acked-by: Joe Stringer <joe@ovn.org> Acked-by: Pravin B Shelar <pshelar@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-09 11:21:59 -08:00
openvswitch: Per NUMA node flow stats. Keep kernel flow stats for each NUMA node rather than each (logical) CPU. This avoids using the per-CPU allocator and removes most of the kernel-side OVS locking overhead otherwise on the top of perf reports and allows OVS to scale better with higher number of threads. With 9 handlers and 4 revalidators netperf TCP_CRR test flow setup rate doubles on a server with two hyper-threaded physical CPUs (16 logical cores each) compared to the current OVS master. Tested with non-trivial flow table with a TCP port match rule forcing all new connections with unique port numbers to OVS userspace. The IP addresses are still wildcarded, so the kernel flows are not considered as exact match 5-tuple flows. This type of flows can be expected to appear in large numbers as the result of more effective wildcarding made possible by improvements in OVS userspace flow classifier. Perf results for this test (master): Events: 305K cycles + 8.43% ovs-vswitchd [kernel.kallsyms] [k] mutex_spin_on_owner + 5.64% ovs-vswitchd [kernel.kallsyms] [k] __ticket_spin_lock + 4.75% ovs-vswitchd ovs-vswitchd [.] find_match_wc + 3.32% ovs-vswitchd libpthread-2.15.so [.] pthread_mutex_lock + 2.61% ovs-vswitchd [kernel.kallsyms] [k] pcpu_alloc_area + 2.19% ovs-vswitchd ovs-vswitchd [.] flow_hash_in_minimask_range + 2.03% swapper [kernel.kallsyms] [k] intel_idle + 1.84% ovs-vswitchd libpthread-2.15.so [.] pthread_mutex_unlock + 1.64% ovs-vswitchd ovs-vswitchd [.] classifier_lookup + 1.58% ovs-vswitchd libc-2.15.so [.] 0x7f4e6 + 1.07% ovs-vswitchd [kernel.kallsyms] [k] memset + 1.03% netperf [kernel.kallsyms] [k] __ticket_spin_lock + 0.92% swapper [kernel.kallsyms] [k] __ticket_spin_lock ... And after this patch: Events: 356K cycles + 6.85% ovs-vswitchd ovs-vswitchd [.] find_match_wc + 4.63% ovs-vswitchd libpthread-2.15.so [.] pthread_mutex_lock + 3.06% ovs-vswitchd [kernel.kallsyms] [k] __ticket_spin_lock + 2.81% ovs-vswitchd ovs-vswitchd [.] flow_hash_in_minimask_range + 2.51% ovs-vswitchd libpthread-2.15.so [.] pthread_mutex_unlock + 2.27% ovs-vswitchd ovs-vswitchd [.] classifier_lookup + 1.84% ovs-vswitchd libc-2.15.so [.] 0x15d30f + 1.74% ovs-vswitchd [kernel.kallsyms] [k] mutex_spin_on_owner + 1.47% swapper [kernel.kallsyms] [k] intel_idle + 1.34% ovs-vswitchd ovs-vswitchd [.] flow_hash_in_minimask + 1.33% ovs-vswitchd ovs-vswitchd [.] rule_actions_unref + 1.16% ovs-vswitchd ovs-vswitchd [.] hindex_node_with_hash + 1.16% ovs-vswitchd ovs-vswitchd [.] do_xlate_actions + 1.09% ovs-vswitchd ovs-vswitchd [.] ofproto_rule_ref + 1.01% netperf [kernel.kallsyms] [k] __ticket_spin_lock ... There is a small increase in kernel spinlock overhead due to the same spinlock being shared between multiple cores of the same physical CPU, but that is barely visible in the netperf TCP_CRR test performance (maybe ~1% performance drop, hard to tell exactly due to variance in the test results), when testing for kernel module throughput (with no userspace activity, handful of kernel flows). On flow setup, a single stats instance is allocated (for the NUMA node 0). As CPUs from multiple NUMA nodes start updating stats, new NUMA-node specific stats instances are allocated. This allocation on the packet processing code path is made to never block or look for emergency memory pools, minimizing the allocation latency. If the allocation fails, the existing preallocated stats instance is used. Also, if only CPUs from one NUMA-node are updating the preallocated stats instance, no additional stats instances are allocated. This eliminates the need to pre-allocate stats instances that will not be used, also relieving the stats reader from the burden of reading stats that are never used. Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com> Acked-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
2014-03-27 12:42:54 -07:00
openvswitch: Per NUMA node flow stats. Keep kernel flow stats for each NUMA node rather than each (logical) CPU. This avoids using the per-CPU allocator and removes most of the kernel-side OVS locking overhead otherwise on the top of perf reports and allows OVS to scale better with higher number of threads. With 9 handlers and 4 revalidators netperf TCP_CRR test flow setup rate doubles on a server with two hyper-threaded physical CPUs (16 logical cores each) compared to the current OVS master. Tested with non-trivial flow table with a TCP port match rule forcing all new connections with unique port numbers to OVS userspace. The IP addresses are still wildcarded, so the kernel flows are not considered as exact match 5-tuple flows. This type of flows can be expected to appear in large numbers as the result of more effective wildcarding made possible by improvements in OVS userspace flow classifier. Perf results for this test (master): Events: 305K cycles + 8.43% ovs-vswitchd [kernel.kallsyms] [k] mutex_spin_on_owner + 5.64% ovs-vswitchd [kernel.kallsyms] [k] __ticket_spin_lock + 4.75% ovs-vswitchd ovs-vswitchd [.] find_match_wc + 3.32% ovs-vswitchd libpthread-2.15.so [.] pthread_mutex_lock + 2.61% ovs-vswitchd [kernel.kallsyms] [k] pcpu_alloc_area + 2.19% ovs-vswitchd ovs-vswitchd [.] flow_hash_in_minimask_range + 2.03% swapper [kernel.kallsyms] [k] intel_idle + 1.84% ovs-vswitchd libpthread-2.15.so [.] pthread_mutex_unlock + 1.64% ovs-vswitchd ovs-vswitchd [.] classifier_lookup + 1.58% ovs-vswitchd libc-2.15.so [.] 0x7f4e6 + 1.07% ovs-vswitchd [kernel.kallsyms] [k] memset + 1.03% netperf [kernel.kallsyms] [k] __ticket_spin_lock + 0.92% swapper [kernel.kallsyms] [k] __ticket_spin_lock ... And after this patch: Events: 356K cycles + 6.85% ovs-vswitchd ovs-vswitchd [.] find_match_wc + 4.63% ovs-vswitchd libpthread-2.15.so [.] pthread_mutex_lock + 3.06% ovs-vswitchd [kernel.kallsyms] [k] __ticket_spin_lock + 2.81% ovs-vswitchd ovs-vswitchd [.] flow_hash_in_minimask_range + 2.51% ovs-vswitchd libpthread-2.15.so [.] pthread_mutex_unlock + 2.27% ovs-vswitchd ovs-vswitchd [.] classifier_lookup + 1.84% ovs-vswitchd libc-2.15.so [.] 0x15d30f + 1.74% ovs-vswitchd [kernel.kallsyms] [k] mutex_spin_on_owner + 1.47% swapper [kernel.kallsyms] [k] intel_idle + 1.34% ovs-vswitchd ovs-vswitchd [.] flow_hash_in_minimask + 1.33% ovs-vswitchd ovs-vswitchd [.] rule_actions_unref + 1.16% ovs-vswitchd ovs-vswitchd [.] hindex_node_with_hash + 1.16% ovs-vswitchd ovs-vswitchd [.] do_xlate_actions + 1.09% ovs-vswitchd ovs-vswitchd [.] ofproto_rule_ref + 1.01% netperf [kernel.kallsyms] [k] __ticket_spin_lock ... There is a small increase in kernel spinlock overhead due to the same spinlock being shared between multiple cores of the same physical CPU, but that is barely visible in the netperf TCP_CRR test performance (maybe ~1% performance drop, hard to tell exactly due to variance in the test results), when testing for kernel module throughput (with no userspace activity, handful of kernel flows). On flow setup, a single stats instance is allocated (for the NUMA node 0). As CPUs from multiple NUMA nodes start updating stats, new NUMA-node specific stats instances are allocated. This allocation on the packet processing code path is made to never block or look for emergency memory pools, minimizing the allocation latency. If the allocation fails, the existing preallocated stats instance is used. Also, if only CPUs from one NUMA-node are updating the preallocated stats instance, no additional stats instances are allocated. This eliminates the need to pre-allocate stats instances that will not be used, also relieving the stats reader from the burden of reading stats that are never used. Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com> Acked-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
2014-03-27 12:42:54 -07:00