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ip frag tuner: cannot rely on MIBs, they are per-cpu #75

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Merged
alan-maguire merged 1 commit into from
Sep 8, 2023
Merged

ip frag tuner: cannot rely on MIBs, they are per-cpu #75

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28 changes: 3 additions & 25 deletions src/ip_frag_tuner.bpf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -20,11 +20,8 @@
#include <bpftune/bpftune.bpf.h>
#include "ip_frag_tuner.h"

/* ratio of failure to success is > 1/2 */
#define REASM_FAIL_THRESHOLD(success, fail) ((success >= 2) && (fail > (success >> 1)))

static __always_inline int defrag(struct net *net, struct fqdir *fqdir,
struct ipstats_mib *ip_stats, int tunable)
int tunable)
{
long mem = BPFTUNE_CORE_READ(fqdir, mem.counter);
long high_thresh = BPFTUNE_CORE_READ(fqdir, high_thresh);
Expand All @@ -39,20 +36,10 @@ static __always_inline int defrag(struct net *net, struct fqdir *fqdir,
* number of fragmentation reassembly failures versus successes.
*/
if (NEARLY_FULL(mem, high_thresh)) {
__u64 reasm_success = BPFTUNE_CORE_READ(ip_stats,
mibs[IPSTATS_MIB_REASMOKS]);
__u64 reasm_fails = BPFTUNE_CORE_READ(ip_stats,
mibs[IPSTATS_MIB_REASMFAILS]);
struct bpftune_event event = { 0 };
long old[3] = {};
long new[3] = {};

bpftune_debug("nearly full, reasm success %ld reasm fail %ld\n",
reasm_success, reasm_fails);

/* too many fragmentation reassembly fails? */
if (REASM_FAIL_THRESHOLD(reasm_success, reasm_fails))
return 0;
old[0] = high_thresh;
new[0] = BPFTUNE_GROW_BY_DELTA(high_thresh);
send_net_sysctl_event(net, IP_FRAG_THRESHOLD_INCREASE,
Expand All @@ -65,15 +52,10 @@ static __always_inline int defrag(struct net *net, struct fqdir *fqdir,
BPF_FENTRY(ip_defrag, struct net *net, struct sk_buff *skb, u32 user)
{
struct fqdir *fqdir = BPFTUNE_CORE_READ(net, ipv4.fqdir);
struct ipstats_mib *ip_stats;

if (!fqdir)
return 0;
ip_stats = BPFTUNE_CORE_READ(net, mib.ip_statistics);

if (!ip_stats)
return 0;
return defrag(net, fqdir, ip_stats, IP_FRAG_MAX_THRESHOLD);
return defrag(net, fqdir, IP_FRAG_MAX_THRESHOLD);
}

#define SKB_DST_NOREF 1UL
Expand All @@ -82,7 +64,6 @@ BPF_FENTRY(ipv6_frag_rcv, struct sk_buff *skb)
{
long unsigned int refdst = BPFTUNE_CORE_READ(skb, _skb_refdst);
struct dst_entry *dst = (struct dst_entry *)(refdst & SKB_DST_PTRMASK);
struct ipstats_mib *ipv6_stats;
struct net_device *dev;
struct fqdir *fqdir;
struct net *net;
Expand All @@ -98,8 +79,5 @@ BPF_FENTRY(ipv6_frag_rcv, struct sk_buff *skb)
fqdir = BPFTUNE_CORE_READ(net, ipv6.fqdir);
if (!fqdir)
return 0;
ipv6_stats = BPFTUNE_CORE_READ(net, mib.ipv6_statistics);
if (!ipv6_stats)
return 0;
return defrag(net, fqdir, ipv6_stats, IP6_FRAG_MAX_THRESHOLD);
return defrag(net, fqdir, IP6_FRAG_MAX_THRESHOLD);
}