On Tue, Feb 06, 2007 at 10:57:07AM -0500, lusec001@xxxxxxxxxx wrote:
> > I want to save the access log of disk in block level.
> > The number of block in disk and the I/O type (R/W) of
> > the request are needed for me.
> >
> > What should I modify to save the log? In block cache
> > code? or EXT{2,3}?
>
> I don't understand so well the question. But, if the information that you
> want is the blocks requested and the type of operation, you need to trace
> the __make_request function
> [http://lxr.free-electrons.com/source/block/ll_rw_blk.c#2905] and print
> the values obtained with the bio paramter
> [http://lxr.free-electrons.com/source/include/linux/bio.h#072]. You could
> do all this with kprobes.
lusec001@xxxxxxxxxx, Ming Zhang <blackmagic02881@xxxxxxxxx>
Hello,
Thank you for the replies.
I modified generic_make_request() in block/ll_rw_blk.c to log
the number of sector on which I/O operation is and the type of
operation (R/W).
Follow is just what I modified in Linux 2.6.20.
--- linux-2.6.20/block/ll_rw_blk.c.sx 2007-02-05 03:44:54.000000000 +0900
+++ linux-2.6.20/block/ll_rw_blk.c 2007-02-12 22:04:29.000000000 +0900
@@ -3121,6 +3121,21 @@
sector_t old_sector;
int ret, nr_sectors = bio_sectors(bio);
dev_t old_dev;
+ struct bio *b;
+ int r;
+
+ r = 0;
+ do {
+ b = bio;
+ printk(KERN_INFO "device:[%s:%d] sector:[%8ld/%8ld] [%5s] %3d\n",
+ b->bi_bdev->bd_disk->disk_name,
+ b->bi_bdev->bd_disk->major,
+ b->bi_sector, b->bi_bdev->bd_disk->capacity,
+ (b->bi_rw << (sizeof(unsigned long) - 1)) ? "write" : "read",
+ r);
+ b = b->bi_next;
+ r++;
+ } while (b);
might_sleep();
/* Test device or partition size, when known. */
And follow is the log messages I got.
....
Feb 12 22:10:03 devel kernel: [ 177.035122] device:[hda:3] sector:[54527992/78165360] [write] 0
Feb 12 22:10:28 devel kernel: [ 202.228368] device:[hda:3] sector:[ 23664/78165360] [write] 0
Feb 12 22:10:28 devel kernel: [ 202.228380] device:[hda:3] sector:[ 23672/78165360] [write] 0
Feb 12 22:10:28 devel kernel: [ 202.228385] device:[hda:3] sector:[ 23680/78165360] [write] 0
Feb 12 22:10:28 devel kernel: [ 202.228600] device:[hda:3] sector:[ 23688/78165360] [write] 0
Feb 12 22:10:35 devel kernel: [ 209.662664] device:[hda:3] sector:[46081848/78165360] [ read] 0
Feb 12 22:10:36 devel kernel: [ 210.407313] device:[hda:3] sector:[33030144/78165360] [ read] 0
Feb 12 22:10:37 devel kernel: [ 211.212951] device:[hda:3] sector:[33046912/78165360] [write] 0
Feb 12 22:10:37 devel kernel: [ 211.212968] device:[hda:3] sector:[33057088/78165360] [write] 0
Feb 12 22:10:37 devel kernel: [ 211.212974] device:[hda:3] sector:[33117232/78165360] [write] 0
Feb 12 22:10:37 devel kernel: [ 211.213342] device:[hda:3] sector:[ 23696/78165360] [write] 0
Feb 12 22:10:37 devel kernel: [ 211.213348] device:[hda:3] sector:[ 23704/78165360] [write] 0
Feb 12 22:10:37 devel kernel: [ 211.213353] device:[hda:3] sector:[ 23712/78165360] [write] 0
Feb 12 22:10:37 devel kernel: [ 211.213356] device:[hda:3] sector:[ 23720/78165360] [write] 0
....
I also test the blktrace and follow is a part of the log of it.
....
3,1 0 1 0.000000000 0 C W 66709160 + 48 [0]
3,1 0 2 0.000543443 0 C W 45597703 + 32 [0]
3,1 0 3 0.000715134 0 C W 66709208 + 8 [0]
3,1 0 4 0.004712097 0 C W 89855 + 256 [0]
3,1 0 5 0.004911340 0 C W 90111 + 8 [0]
3,1 0 6 9.981945195 0 C W 90119 + 40 [0]
3,1 0 7 9.982134057 0 C W 90159 + 8 [0]
3,1 0 8 10.008405332 0 C W 72256056 + 8 [0]
3,1 0 9 10.008966459 0 C W 66709216 + 32 [0]
3,1 0 10 10.009152830 0 C W 66709248 + 8 [0]
3,1 0 11 10.090253953 0 C W 72206904 + 8 [0]
....
Let me know if something wrong in my post. Thank you!
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