#!/usr/bin/bpftrace

#include <linux/genhd.h>
#include <linux/blkdev.h>

BEGIN
{
	printf("Tracing submit bio vcnt... Hit Ctrl-C to end.\n");

}

kprobe:__writepage,
kprobe:move_to_new_page,
kprobe:do_writepages,
kprobe:write_one_page
{
	@wb[tid] = 1;
}

kretprobe:__writepage,
kretprobe:move_to_new_page,
kretprobe:do_writepages,
kretprobe:write_one_page
{
	@wb[tid] = 0;
}

kprobe:submit_bio
/@wb[tid] == 1/
{
	$bio = (struct bio *)arg0;
	$gd = (struct gendisk *)$bio->bi_disk;

		$vcnt= $bio->bi_vcnt;
		$maxvcnt= $bio->bi_max_vecs;
		$size= $bio->bi_iter.bi_size;

		@["vcnt", $gd->disk_name]  = hist($vcnt);
		@["maxvcnt", $gd->disk_name] = hist($maxvcnt);
		@["size", $gd->disk_name] = hist($size);
}

END {
	clear(@wb);
}