Messages in this thread | | | From | Jay Vosburgh <> | Subject | Re: [PATCH] tcp: Add memory pressure flag to sockstat | Date | Fri, 14 Jul 2023 15:45:02 -0700 |
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Jamie Bainbridge <jamie.bainbridge@gmail.com> wrote:
>When tuning a system it can be helpful to know whether the protocol is >in memory pressure state or not. This can be determined by corresponding >the number of pages in "net.ipv4.tcp_mem" with the current allocation, >but a global variable already tracks this as the source of truth. > >Expose that variable in sockstat where other protocol memory usage is >already reported. > >Add "pressure" which is 0 in normal state and 1 under pressure: > > # grep TCP /proc/net/sockstat > TCP: inuse 5 orphan 0 tw 0 alloc 7 mem 1 pressure 0 > > # grep TCP /proc/net/sockstat > TCP: inuse 5 orphan 0 tw 0 alloc 7 mem 1 pressure 1
Isn't this already available in /proc/net/protocols?
protocol size sockets memory press maxhdr slab module cl co di ac io in de sh ss gs se re sp bi br ha uh gp em [...] UDP 1472 7 6 NI 0 yes kernel y y y n y y y n y y y y y n n y y y n TCP 2512 5 1 no 320 yes kernel y y y y y y y y y y y y y n y y y y y
-J
>Tested by writing a large value to global variable tcp_memory_pressure >(it usually stores jiffies when memory pressure was entered) and not >just by code review or editing example output. > >Signed-off-by: Jamie Bainbridge <jamie.bainbridge@gmail.com> >--- > net/ipv4/proc.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > >diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c >index eaf1d3113b62f7dc93fdc7b7c4041140ac63bf69..f4c5ced2de49d5c6d7f5d7ccdaa76c89dcf8c932 100644 >--- a/net/ipv4/proc.c >+++ b/net/ipv4/proc.c >@@ -51,16 +51,17 @@ > static int sockstat_seq_show(struct seq_file *seq, void *v) > { > struct net *net = seq->private; >- int orphans, sockets; >+ int orphans, sockets, tcp_pressure; > > orphans = tcp_orphan_count_sum(); > sockets = proto_sockets_allocated_sum_positive(&tcp_prot); >+ tcp_pressure = READ_ONCE(tcp_memory_pressure) ? 1 : 0; > > socket_seq_show(seq); >- seq_printf(seq, "TCP: inuse %d orphan %d tw %d alloc %d mem %ld\n", >+ seq_printf(seq, "TCP: inuse %d orphan %d tw %d alloc %d mem %ld pressure %d\n", > sock_prot_inuse_get(net, &tcp_prot), orphans, > refcount_read(&net->ipv4.tcp_death_row.tw_refcount) - 1, >- sockets, proto_memory_allocated(&tcp_prot)); >+ sockets, proto_memory_allocated(&tcp_prot), tcp_pressure); > seq_printf(seq, "UDP: inuse %d mem %ld\n", > sock_prot_inuse_get(net, &udp_prot), > proto_memory_allocated(&udp_prot)); >-- >2.41.0 > >
--- -Jay Vosburgh, jay.vosburgh@canonical.com
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