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authorPaolo Abeni <pabeni@redhat.com>2016-02-12 15:43:53 +0100
committerDavid S. Miller <davem@davemloft.net>2016-02-16 20:21:48 -0500
commit911362c70df5b766c243dc297fadeaced786ffd8 (patch)
tree82d2783ae0067d762f88f9cbb51b5a15eb7d339b /net/Kconfig
parent64f63d59ba782ec317fca150895ef8dc6ddbff4b (diff)
downloadlinux-911362c70df5b766c243dc297fadeaced786ffd8.tar.bz2
net: add dst_cache support
This patch add a generic, lockless dst cache implementation. The need for lock is avoided updating the dst cache fields only in per cpu scope, and requiring that the cache manipulation functions are invoked with the local bh disabled. The refresh_ts and reset_ts fields are used to ensure the cache consistency in case of cuncurrent cache update (dst_cache_set*) and reset operation (dst_cache_reset). Consider the following scenario: CPU1: CPU2: <cache lookup with emtpy cache: it fails> <get dst via uncached route lookup> <related configuration changes> dst_cache_reset() dst_cache_set() The dst entry set passed to dst_cache_set() should not be used for later dst cache lookup, because it's obtained using old configuration values. Since the refresh_ts is updated only on dst_cache lookup, the cached value in the above scenario will be discarded on the next lookup. Signed-off-by: Paolo Abeni <pabeni@redhat.com> Suggested-and-acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/Kconfig')
-rw-r--r--net/Kconfig4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/Kconfig b/net/Kconfig
index 174354618f8a..b80efecfc1a0 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -392,6 +392,10 @@ config LWTUNNEL
weight tunnel endpoint. Tunnel encapsulation parameters are stored
with light weight tunnel state associated with fib routes.
+config DST_CACHE
+ bool "dst cache"
+ default n
+
endif # if NET
# Used by archs to tell that they support BPF_JIT