Hello, On Sun, 14 May 2023, Abhijeet Rastogi wrote: > Current range [8, 20] is set purely due to historical reasons > because at the time, ~1M (2^20) was considered sufficient. > With this change, 27 is the upper limit for 64-bit, 20 otherwise. > > Previous change regarding this limit is here. > > Link: https://lore.kernel.org/all/86eabeb9dd62aebf1e2533926fdd13fed48bab1f.1631289960.git.aclaudi@xxxxxxxxxx/T/#u > > Signed-off-by: Abhijeet Rastogi <abhijeet.1989@xxxxxxxxx> > --- > The conversation for this started at: > > https://www.spinics.net/lists/netfilter/msg60995.html > > The upper limit for algo is any bit size less than 32, so this > change will allow us to set bit size > 20. Today, it is common to have > RAM available to handle greater than 2^20 connections per-host. > > Distros like RHEL already allow setting limits higher than 20. > --- > Changes in v2: > - Lower the ranges, 27 for 64bit, 20 otherwise > - Link to v1: https://lore.kernel.org/r/20230412-increase_ipvs_conn_tab_bits-v1-1-60a4f9f4c8f2@xxxxxxxxx > --- > net/netfilter/ipvs/Kconfig | 26 +++++++++++++------------- > net/netfilter/ipvs/ip_vs_conn.c | 4 ++-- > 2 files changed, 15 insertions(+), 15 deletions(-) > > diff --git a/net/netfilter/ipvs/Kconfig b/net/netfilter/ipvs/Kconfig > index 271da8447b29..aac5d6bd82e6 100644 > --- a/net/netfilter/ipvs/Kconfig > +++ b/net/netfilter/ipvs/Kconfig > @@ -44,7 +44,8 @@ config IP_VS_DEBUG > > config IP_VS_TAB_BITS > int "IPVS connection table size (the Nth power of 2)" > - range 8 20 > + range 8 20 if !64BIT > + range 8 27 if 64BIT > default 12 > help > The IPVS connection hash table uses the chaining scheme to handle > @@ -52,18 +53,17 @@ config IP_VS_TAB_BITS > reduce conflicts when there are hundreds of thousands of connections > in the hash table. > > - Note the table size must be power of 2. The table size will be the > - value of 2 to the your input number power. The number to choose is > - from 8 to 20, the default number is 12, which means the table size > - is 4096. Don't input the number too small, otherwise you will lose > - performance on it. You can adapt the table size yourself, according > - to your virtual server application. It is good to set the table size > - not far less than the number of connections per second multiplying > - average lasting time of connection in the table. For example, your > - virtual server gets 200 connections per second, the connection lasts > - for 200 seconds in average in the connection table, the table size > - should be not far less than 200x200, it is good to set the table > - size 32768 (2**15). > + Note the table size must be power of 2. The table size will be the value > + of 2 to the your input number power. The number to choose is from 8 to 27 > + for 64BIT(20 otherwise), the default number is 12, which means the table > + size is 4096. Don't input the number too small, otherwise you will lose > + performance on it. You can adapt the table size yourself, according to > + your virtual server application. It is good to set the table size not far > + less than the number of connections per second multiplying average lasting > + time of connection in the table. For example, your virtual server gets > + 200 connections per second, the connection lasts for 200 seconds in > + average in the connection table, the table size should be not far less > + than 200x200, it is good to set the table size 32768 (2**15). Can you keep the previous line width of the above help because on standard 80-width window the help now gets truncated in make menuconfig. After that I'll send a patch on top of yours to limit the rows depending on the memory. > Another note that each connection occupies 128 bytes effectively and > each hash entry uses 8 bytes, so you can estimate how much memory is > diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c > index 13534e02346c..e1b9b52909a5 100644 > --- a/net/netfilter/ipvs/ip_vs_conn.c > +++ b/net/netfilter/ipvs/ip_vs_conn.c > @@ -1484,8 +1484,8 @@ int __init ip_vs_conn_init(void) > int idx; > > /* Compute size and mask */ > - if (ip_vs_conn_tab_bits < 8 || ip_vs_conn_tab_bits > 20) { > - pr_info("conn_tab_bits not in [8, 20]. Using default value\n"); > + if (ip_vs_conn_tab_bits < 8 || ip_vs_conn_tab_bits > 27) { > + pr_info("conn_tab_bits not in [8, 27]. Using default value\n"); > ip_vs_conn_tab_bits = CONFIG_IP_VS_TAB_BITS; > } > ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits; > > --- Regards -- Julian Anastasov <ja@xxxxxx>
