Commit c386578f authored by Steffen Klassert's avatar Steffen Klassert
Browse files

xfrm: Let the flowcache handle its size by default. 



The xfrm flowcache size is limited by the flowcache limit
(4096 * number of online cpus) and the xfrm garbage collector
threshold (2 * 32768), whatever is reached first. This means
that we can hit the garbage collector limit only on systems
with more than 16 cpus. On such systems we simply refuse
new allocations if we reach the limit, so new flows are dropped.
On syslems with 16 or less cpus, we hit the flowcache limit.
In this case, we shrink the flow cache instead of refusing new
flows.

We increase the xfrm garbage collector threshold to INT_MAX
to get the same behaviour, independent of the number of cpus.

The xfrm garbage collector threshold can still be set below
the flowcache limit to reduce the memory usage of the flowcache.

Tested-by: default avatarDan Streetman <dan.streetman@canonical.com>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent 8a4683a5

Documentation/networking/ip-sysctl.txt

+4 −2
Original line number Diff line number Diff line
@@ -1199,7 +1199,8 @@ tag - INTEGER 
xfrm4_gc_thresh - INTEGER

	The threshold at which we will start garbage collecting for IPv4

	destination cache entries.  At twice this value the system will

	refuse new allocations.

	refuse new allocations. The value must be set below the flowcache

	limit (4096 * number of online cpus) to take effect.



igmp_link_local_mcast_reports - BOOLEAN

	Enable IGMP reports for link local multicast groups in the
@@ -1645,7 +1646,8 @@ ratelimit - INTEGER 
xfrm6_gc_thresh - INTEGER

	The threshold at which we will start garbage collecting for IPv6

	destination cache entries.  At twice this value the system will

	refuse new allocations.

	refuse new allocations. The value must be set below the flowcache

	limit (4096 * number of online cpus) to take effect.





IPv6 Update by:

net/ipv4/xfrm4_policy.c

+1 −1
Original line number Diff line number Diff line
@@ -246,7 +246,7 @@ static struct dst_ops xfrm4_dst_ops = { 
	.destroy =		xfrm4_dst_destroy,

	.ifdown =		xfrm4_dst_ifdown,

	.local_out =		__ip_local_out,

	.gc_thresh =		32768,

	.gc_thresh =		INT_MAX,

};



static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {

net/ipv6/xfrm6_policy.c

+1 −1
Original line number Diff line number Diff line
@@ -287,7 +287,7 @@ static struct dst_ops xfrm6_dst_ops = { 
	.destroy =		xfrm6_dst_destroy,

	.ifdown =		xfrm6_dst_ifdown,

	.local_out =		__ip6_local_out,

	.gc_thresh =		32768,

	.gc_thresh =		INT_MAX,

};



static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {

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