[PATCH] inetpeer: use div64_ul() and clamp_val() calculate inet_peer_threshold

[Yejune Deng]

In inet_initpeers(), struct inet_peer on IA32 uses 128 bytes in nowdays.
Get rid of the cascade and use div64_ul() and clamp_val() calculate that
will not need to be adjusted in the future as suggested by Eric Dumazet.

Suggested-by: Eric Dumazet <eric.duma...@gmail.com>
Signed-off-by: Yejune Deng <yejune.d...@gmail.com>
---
 net/ipv4/inetpeer.c | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index ff327a62c9ce..da21dfce24d7 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -65,7 +65,7 @@ EXPORT_SYMBOL_GPL(inet_peer_base_init);
 #define PEER_MAX_GC 32
 
 /* Exported for sysctl_net_ipv4.  */
-int inet_peer_threshold __read_mostly = 65536 + 128;   /* start to throw 
entries more
+int inet_peer_threshold __read_mostly; /* start to throw entries more
                                         * aggressively at this stage */
 int inet_peer_minttl __read_mostly = 120 * HZ; /* TTL under high load: 120 sec 
*/
 int inet_peer_maxttl __read_mostly = 10 * 60 * HZ;     /* usual time to live: 
10 min */
@@ -73,20 +73,13 @@ int inet_peer_maxttl __read_mostly = 10 * 60 * HZ;  /* 
usual time to live: 10 min
 /* Called from ip_output.c:ip_init  */
 void __init inet_initpeers(void)
 {
-       struct sysinfo si;
+       u64 nr_entries;
 
-       /* Use the straight interface to information about memory. */
-       si_meminfo(&si);
-       /* The values below were suggested by Alexey Kuznetsov
-        * <kuz...@ms2.inr.ac.ru>.  I don't have any opinion about the values
-        * myself.  --SAW
-        */
-       if (si.totalram <= (32768*1024)/PAGE_SIZE)
-               inet_peer_threshold >>= 1; /* max pool size about 1MB on IA32 */
-       if (si.totalram <= (16384*1024)/PAGE_SIZE)
-               inet_peer_threshold >>= 1; /* about 512KB */
-       if (si.totalram <= (8192*1024)/PAGE_SIZE)
-               inet_peer_threshold >>= 2; /* about 128KB */
+        /* 1% of physical memory */
+       nr_entries = div64_ul((u64)totalram_pages() << PAGE_SHIFT,
+                             100 * L1_CACHE_ALIGN(sizeof(struct inet_peer)));
+
+       inet_peer_threshold = clamp_val(nr_entries, 4096, 65536 + 128);
 
        peer_cachep = kmem_cache_create("inet_peer_cache",
                        sizeof(struct inet_peer),
-- 
2.29.0