skb stats

hello.c

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>

int init_module(void)
{
        printk(KERN_INFO "skb_count=%ld\n", __get_skb_count());
        return 0;
}

void cleanup_module(void)
{
        printk(KERN_INFO "quit.\n");
}

MODULE_LICENSE("GPL");

Makefile

obj-m += hello.o

all:
        make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:
        make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

skb_stats.stap

#!/usr/bin/env stap

global skb_cnt = 0

probe begin
{
        warn("Hit Ctrl-C to end.\n")
}

probe end
{
        printf("\nskb count: %d\n", skb_cnt)
}

// skbs[$skb] = backtrace()
// skbs[$skb] = execname()
probe kernel.statement("*@net/core/skbuff.c:1743"),
        kernel.statement("*@net/core/skbuff.c:499"),
        kernel.function("__build_skb_around@net/core/skbuff.c")
{
        skb_cnt++
}

probe kernel.statement("*@net/core/skbuff.c:911"),
        kernel.statement("*@net/core/skbuff.c:1134"),
        kernel.statement("*@net/core/skbuff.c:1154"),
        kernel.statement("*@net/core/skbuff.c:1173"),
        kernel.statement("*@net/core/skbuff.c:883")
{
        skb_cnt--
}

probe kernel.function("napi_skb_free_stolen_head")
{
        print_stack(backtrace())
        skb_cnt--
}