From: Eric Dumazet <[EMAIL PROTECTED]> Date: Thu, 01 Nov 2007 11:16:20 +0100
> As done two years ago on IP route cache table (commit > 22c047ccbc68fa8f3fa57f0e8f906479a062c426) , we can avoid using one lock per > hash bucket for the huge TCP/DCCP hash tables. > > On a typical x86_64 platform, this saves about 2MB or 4MB of ram, for litle > performance differences. (we hit a different cache line for the rwlock, but > then the bucket cache line have a better sharing factor among cpus, since we > dirty it less often) > > Using a 'small' table of hashed rwlocks should be more than enough to provide > correct SMP concurrency between different buckets, without using too much > memory. Sizing of this table depends on NR_CPUS and various CONFIG settings. > > This patch provides some locking abstraction that may ease a future work > using > a different model for TCP/DCCP table. > > Signed-off-by: Eric Dumazet <[EMAIL PROTECTED]> Nice work Eric. I've tossed this into my local tree and we'll let this cook for a few days. If no problems crop up I will submit it for 2.6.24 because the memory savings is non-trivial. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
