From 095dc8e0c3686d586a01a50abc3e1bb9ac633054 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 26 May 2015 07:55:34 -0700 Subject: tcp: fix/cleanup inet_ehash_locks_alloc() If tcp ehash table is constrained to a very small number of buckets (eg boot parameter thash_entries=128), then we can crash if spinlock array has more entries. While we are at it, un-inline inet_ehash_locks_alloc() and make following changes : - Budget 2 cache lines per cpu worth of 'spinlocks' - Try to kmalloc() the array to avoid extra TLB pressure. (Most servers at Google allocate 8192 bytes for this hash table) - Get rid of various #ifdef Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/inet_hashtables.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'net/ipv4') diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 3766bddb3e8a..185efef0f125 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -609,3 +610,33 @@ void inet_hashinfo_init(struct inet_hashinfo *h) } } EXPORT_SYMBOL_GPL(inet_hashinfo_init); + +int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo) +{ + unsigned int i, nblocks = 1; + + if (sizeof(spinlock_t) != 0) { + /* allocate 2 cache lines or at least one spinlock per cpu */ + nblocks = max_t(unsigned int, + 2 * L1_CACHE_BYTES / sizeof(spinlock_t), + 1); + nblocks = roundup_pow_of_two(nblocks * num_possible_cpus()); + + /* no more locks than number of hash buckets */ + nblocks = min(nblocks, hashinfo->ehash_mask + 1); + + hashinfo->ehash_locks = kmalloc_array(nblocks, sizeof(spinlock_t), + GFP_KERNEL | __GFP_NOWARN); + if (!hashinfo->ehash_locks) + hashinfo->ehash_locks = vmalloc(nblocks * sizeof(spinlock_t)); + + if (!hashinfo->ehash_locks) + return -ENOMEM; + + for (i = 0; i < nblocks; i++) + spin_lock_init(&hashinfo->ehash_locks[i]); + } + hashinfo->ehash_locks_mask = nblocks - 1; + return 0; +} +EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc); -- cgit v1.2.1