db9ca5cacb
Jim Westfall says: ==================== ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY This used to be the previous behavior in older kernels but became broken in a263b3093641f (ipv4: Make neigh lookups directly in output packet path) and then later removed because it was broken in 0bb4087cbec0 (ipv4: Fix neigh lookup keying over loopback/point-to-point devices) Not having this results in there being an arp entry for every remote ip address that the device talks to. Given a fairly active device it can cause the arp table to become huge and/or having to add/purge large number of entires to keep within table size thresholds. $ ip -4 neigh show nud noarp | grep tun | wc -l 55850 $ lnstat -k arp_cache:entries,arp_cache:allocs,arp_cache:destroys -c 10 arp_cach|arp_cach|arp_cach| entries| allocs|destroys| 81493|620166816|620126069| 101867| 10186| 0| 113854| 5993| 0| 118773| 2459| 0| 27937| 18579| 63998| 39256| 5659| 0| 56231| 8487| 0| 65602| 4685| 0| 79697| 7047| 0| 90733| 5517| 0| v2: - fixes coding style issues ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.