readahead02: fix read_ahead_kb file not found

PATCH Superseded [email protected] 2 participants 5 messages Sep 2, 2016 – Sep 13, 2016

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author

2016-09-02 10:42 UTC #0 lore raw

PATCH v2 1/1 readahead02: fix read_ahead_kb file not found

From: Naresh Kamboju <[email protected]>

Test case is looking for read_ahead_kb file on a partition device (8:2) and not on block device (8:0/8:16/8:32/8:48). The appropriate block device that holds the partition can be found at queue/read_ahead_kb entry.

Before patch readahead02 test broken,
readahead02 1 TBROK : safe_file_ops.c:144: Failed to open FILE
'/sys/dev/block/8:2/queue/read_ahead_kb' for reading at readahead02.c:197: errno=ENOENT(2): No such file or directory

After applying patch,

readahead02    0  TINFO  :  creating test file of size: 67108864
readahead02    0  TINFO  :  max readahead size is: 131072
readahead02    0  TINFO  :  read_testfile(0)
readahead02    0  TINFO  :  max readahead size is: 131072
readahead02    0  TINFO  :  read_testfile(1)
readahead02    0  TINFO  :  max readahead size is: 131072
readahead02    1  TPASS  :  expected ret success - returned value = 0
readahead02    2  TPASS  :  offset is still at 0 as expected
readahead02    0  TINFO  :  read_testfile(0) took: 1437202 usec
readahead02    0  TINFO  :  read_testfile(1) took: 1361915 usec
readahead02    0  TINFO  :  read_testfile(0) read: 67108864 bytes
readahead02    0  TINFO  :  read_testfile(1) read: 0 bytes
readahead02    3  TPASS  :  readahead saved some I/O
readahead02    0  TINFO  :  cache can hold at least: 157404 kB
readahead02    0  TINFO  :  read_testfile(0) used cache: 65332 kB
readahead02    0  TINFO  :  read_testfile(1) used cache: 65636 kB
readahead02    4  TPASS  :  using cache as expected

Patch tested on aarch64 and x86_64.

Signed-off-by Naresh Kamboju <[email protected]>

---
 testcases/kernel/syscalls/readahead/readahead02.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

testcases/kernel/syscalls/readahead/readahead02.c +7 -2

index 53278be..97ab0a8 100644
@@ -192,8 +192,13 @@ static long get_device_readahead(const char *fname)
 
 	if (stat(fname, &st) == -1)
 		tst_brkm(TBROK | TERRNO, cleanup, "stat");
-	snprintf(buf, sizeof(buf), "/sys/dev/block/%d:%d/queue/read_ahead_kb",
-		 major(st.st_dev), minor(st.st_dev));
+	if (minor(st.st_dev)) {
+		snprintf(buf, sizeof(buf), "/sys/dev/block/%d:%d/../queue/read_ahead_kb",
+			major(st.st_dev), minor(st.st_dev));
+	} else {
+		snprintf(buf, sizeof(buf), "/sys/dev/block/%d:%d/queue/read_ahead_kb",
+			major(st.st_dev), minor(st.st_dev));
+	}
 	SAFE_FILE_SCANF(cleanup, buf, "%ld", &ra_kb);
 
 	return ra_kb * 1024;

Signature · 1 line

1.9.1

Jan Stancek

2016-09-05 07:36 UTC #1 lore raw

PATCH v2 1/1 readahead02: fix read_ahead_kb file not found

----- Original Message -----

Quoted 28 lines

From: "naresh kamboju" <[email protected]>
To: [email protected], [email protected]
Cc: [email protected], "fengguang wu" <[email protected]>, "graeme gregory" <[email protected]>, "milosz wasilewski" <[email protected]>
Sent: Friday, 2 September, 2016 12:42:33 PM
Subject: [LTP] [v2] readahead02: fix read_ahead_kb file not found
From: Naresh Kamboju <[email protected]>
Test case is looking for read_ahead_kb file on a partition device (8:2) and not on block device (8:0/8:16/8:32/8:48). The appropriate block device that holds the partition can be found at queue/read_ahead_kb entry.
Before patch readahead02 test broken,
readahead02 1 TBROK : safe_file_ops.c:144: Failed to open FILE
'/sys/dev/block/8:2/queue/read_ahead_kb' for reading at readahead02.c:197: errno=ENOENT(2): No such file or directory
After applying patch,
readahead02    0  TINFO  :  creating test file of size: 67108864
readahead02    0  TINFO  :  max readahead size is: 131072
readahead02    0  TINFO  :  read_testfile(0)
readahead02    0  TINFO  :  max readahead size is: 131072
readahead02    0  TINFO  :  read_testfile(1)
readahead02    0  TINFO  :  max readahead size is: 131072
readahead02    1  TPASS  :  expected ret success - returned value = 0
readahead02    2  TPASS  :  offset is still at 0 as expected
readahead02    0  TINFO  :  read_testfile(0) took: 1437202 usec

Quoted 8 lines

readahead02    0  TINFO  :  read_testfile(1) took: 1361915 usec
readahead02    0  TINFO  :  read_testfile(0) read: 67108864 bytes
readahead02    0  TINFO  :  read_testfile(1) read: 0 bytes
readahead02    3  TPASS  :  readahead saved some I/O
readahead02    0  TINFO  :  cache can hold at least: 157404 kB
readahead02    0  TINFO  :  read_testfile(0) used cache: 65332 kB
readahead02    0  TINFO  :  read_testfile(1) used cache: 65636 kB
readahead02    4  TPASS  :  using cache as expected

This doesn't seem to be true for all entries under /sys/dev/block. If I ran your patch on lvm, testcase fails:

# ./readahead02 
readahead02    0  TINFO  :  creating test file of size: 67108864
readahead02    1  TBROK  :  safe_file_ops.c:144: Failed to open FILE '/sys/dev/block/253:1/../queue/read_ahead_kb' for reading at readahead02.c:202: errno=ENOENT(2): No such file or directory
readahead02    2  TBROK  :  safe_file_ops.c:144: Remaining cases broken

# ll /sys/dev/block/253:1
lrwxrwxrwx. 1 root root 0 Sep  5 09:21 /sys/dev/block/253:1 -> ../../devices/virtual/block/dm-1

# ll /sys/dev/block/253:1/
total 0
-r--r--r--. 1 root root 4096 Sep  5 09:25 alignment_offset
-rw-r--r--. 1 root root 4096 Sep  5 09:25 badblocks
lrwxrwxrwx. 1 root root    0 Sep  5 09:21 bdi -> ../../bdi/253:1
-r--r--r--. 1 root root 4096 Sep  5 09:25 capability
-r--r--r--. 1 root root 4096 Sep  5 09:25 dev
-r--r--r--. 1 root root 4096 Sep  5 09:25 discard_alignment
drwxr-xr-x. 2 root root    0 Sep  5 09:25 dm
-r--r--r--. 1 root root 4096 Sep  5 09:25 ext_range
drwxr-xr-x. 2 root root    0 Sep  5 09:25 holders
-r--r--r--. 1 root root 4096 Sep  5 09:25 inflight
drwxr-xr-x. 2 root root    0 Sep  5 09:25 integrity
drwxr-xr-x. 2 root root    0 Sep  5 09:25 power
drwxr-xr-x. 2 root root    0 Sep  5 09:25 queue
-r--r--r--. 1 root root 4096 Sep  5 09:25 range
-r--r--r--. 1 root root 4096 Sep  5 09:25 removable
-r--r--r--. 1 root root 4096 Sep  5 09:25 ro
-r--r--r--. 1 root root 4096 Sep  5 09:25 size
drwxr-xr-x. 2 root root    0 Sep  5 09:25 slaves
-r--r--r--. 1 root root 4096 Sep  5 09:25 stat
lrwxrwxrwx. 1 root root    0 Sep  5 09:21 subsystem -> ../../../../class/block
drwxr-xr-x. 2 root root    0 Sep  5 09:25 trace
-rw-r--r--. 1 root root 4096 Sep  5 09:25 uevent

# lsblk 
NAME                        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda                         252:0    0   35G  0 disk 
├─vda1                      252:1    0  500M  0 part /boot
└─vda2                      252:2    0 34.5G  0 part 
  ├─rhel_dhcp--27--118-swap 253:0    0    2G  0 lvm  [SWAP]
  └─rhel_dhcp--27--118-root 253:1    0 32.5G  0 lvm  /

# uname -r
4.7.0-rc7+

Regards,
Jan

Naresh Kamboju

author

2016-09-06 12:33 UTC #2 lore raw

PATCH v2 1/1 readahead02: fix read_ahead_kb file not found

Hi Jan,

Quoted 40 lines · Jan Stancek

----- Original Message -----
Quoted 28 lines
From: "naresh kamboju" <[email protected]>
To: [email protected], [email protected]
Cc: [email protected], "fengguang wu" <[email protected]>, "graeme gregory" <[email protected]>, "milosz wasilewski" <[email protected]>
Sent: Friday, 2 September, 2016 12:42:33 PM
Subject: [LTP] [v2] readahead02: fix read_ahead_kb file not found
From: Naresh Kamboju <[email protected]>
Test case is looking for read_ahead_kb file on a partition device (8:2) and not on block device (8:0/8:16/8:32/8:48). The appropriate block device that holds the partition can be found at queue/read_ahead_kb entry.
Before patch readahead02 test broken,
readahead02 1 TBROK : safe_file_ops.c:144: Failed to open FILE
'/sys/dev/block/8:2/queue/read_ahead_kb' for reading at readahead02.c:197: errno=ENOENT(2): No such file or directory
After applying patch,
readahead02    0  TINFO  :  creating test file of size: 67108864
readahead02    0  TINFO  :  max readahead size is: 131072
readahead02    0  TINFO  :  read_testfile(0)
readahead02    0  TINFO  :  max readahead size is: 131072
readahead02    0  TINFO  :  read_testfile(1)
readahead02    0  TINFO  :  max readahead size is: 131072
readahead02    1  TPASS  :  expected ret success - returned value = 0
readahead02    2  TPASS  :  offset is still at 0 as expected
readahead02    0  TINFO  :  read_testfile(0) took: 1437202 usec
Quoted 8 lines
readahead02    0  TINFO  :  read_testfile(1) took: 1361915 usec
readahead02    0  TINFO  :  read_testfile(0) read: 67108864 bytes
readahead02    0  TINFO  :  read_testfile(1) read: 0 bytes
readahead02    3  TPASS  :  readahead saved some I/O
readahead02    0  TINFO  :  cache can hold at least: 157404 kB
readahead02    0  TINFO  :  read_testfile(0) used cache: 65332 kB
readahead02    0  TINFO  :  read_testfile(1) used cache: 65636 kB
readahead02    4  TPASS  :  using cache as expected

Quoted 2 lines

This doesn't seem to be true for all entries under /sys/dev/block. If I ran your patch on lvm, testcase fails:

Thanks for your findings.
I have tested on Ubuntu and Debian.

We have to refactor this test case to work on multi distribution. I have to find a machine running CentOS and debug this case.

Quoted 17 lines

# ./readahead02
readahead02    0  TINFO  :  creating test file of size: 67108864
readahead02    1  TBROK  :  safe_file_ops.c:144: Failed to open FILE '/sys/dev/block/253:1/../queue/read_ahead_kb' for reading at readahead02.c:202: errno=ENOENT(2): No such file or directory
readahead02    2  TBROK  :  safe_file_ops.c:144: Remaining cases broken

# ll /sys/dev/block/253:1
lrwxrwxrwx. 1 root root 0 Sep  5 09:21 /sys/dev/block/253:1 -> ../../devices/virtual/block/dm-1

# ll /sys/dev/block/253:1/
total 0

(quoted diff) +0 -2

-r--r--r--. 1 root root 4096 Sep  5 09:25 alignment_offset
-rw-r--r--. 1 root root 4096 Sep  5 09:25 badblocks

lrwxrwxrwx. 1 root root 0 Sep 5 09:21 bdi -> ../../bdi/253:1

(quoted diff) +0 -3

-r--r--r--. 1 root root 4096 Sep  5 09:25 capability
-r--r--r--. 1 root root 4096 Sep  5 09:25 dev
-r--r--r--. 1 root root 4096 Sep  5 09:25 discard_alignment

Quoted 7 lines

drwxr-xr-x. 2 root root    0 Sep  5 09:25 dm
-r--r--r--. 1 root root 4096 Sep  5 09:25 ext_range
drwxr-xr-x. 2 root root    0 Sep  5 09:25 holders
-r--r--r--. 1 root root 4096 Sep  5 09:25 inflight
drwxr-xr-x. 2 root root    0 Sep  5 09:25 integrity
drwxr-xr-x. 2 root root    0 Sep  5 09:25 power
drwxr-xr-x. 2 root root    0 Sep  5 09:25 queue

read_ahead_kb file should present in queue folder. Is this test case pass on this machine *without* my patch ? /sys/dev/block/253:1/queue/read_ahead_kb

Quoted 10 lines

(quoted diff) +0 -4

-r--r--r--. 1 root root 4096 Sep  5 09:25 range
-r--r--r--. 1 root root 4096 Sep  5 09:25 removable
-r--r--r--. 1 root root 4096 Sep  5 09:25 ro
-r--r--r--. 1 root root 4096 Sep  5 09:25 size

drwxr-xr-x. 2 root root    0 Sep  5 09:25 slaves
-r--r--r--. 1 root root 4096 Sep  5 09:25 stat
lrwxrwxrwx. 1 root root    0 Sep  5 09:21 subsystem -> ../../../../class/block
drwxr-xr-x. 2 root root    0 Sep  5 09:25 trace
-rw-r--r--. 1 root root 4096 Sep  5 09:25 uevent

Quoted 7 lines

# lsblk
NAME                        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda                         252:0    0   35G  0 disk
├─vda1                      252:1    0  500M  0 part /boot
└─vda2                      252:2    0 34.5G  0 part
  ├─rhel_dhcp--27--118-swap 253:0    0    2G  0 lvm  [SWAP]
  └─rhel_dhcp--27--118-root 253:1    0 32.5G  0 lvm  /

Is it a physical drive or Virtual drive ?
In general I use vda for KVM.

Quoted 3 lines

# uname -r
4.7.0-rc7+

Thank you.

Best regards
Naresh Kamboju

Quoted 3 lines

Regards,
Jan

Jan Stancek

2016-09-06 14:22 UTC #3 lore raw

PATCH v2 1/1 readahead02: fix read_ahead_kb file not found

----- Original Message -----

Quoted 54 lines

From: "Naresh Kamboju" <[email protected]>
To: "Jan Stancek" <[email protected]>
Cc: "chrubis" <[email protected]>, [email protected], [email protected], "fengguang wu" <[email protected]>, "graeme gregory" <[email protected]>, "milosz wasilewski" <[email protected]>
Sent: Tuesday, 6 September, 2016 2:33:58 PM
Subject: Re: [LTP] [v2] readahead02: fix read_ahead_kb file not found
Hi Jan,
Quoted 43 lines · Jan Stancek
----- Original Message -----
Quoted 39 lines
From: "naresh kamboju" <[email protected]>
To: [email protected], [email protected]
Cc: [email protected], "fengguang wu" <[email protected]>, "graeme gregory" <[email protected]>,
"milosz wasilewski" <[email protected]>
Sent: Friday, 2 September, 2016 12:42:33 PM
Subject: [LTP] [v2] readahead02: fix read_ahead_kb file not found
From: Naresh Kamboju <[email protected]>
Test case is looking for read_ahead_kb file on a partition device (8:2) and
not on block device (8:0/8:16/8:32/8:48). The appropriate block device that
holds the partition can be found at queue/read_ahead_kb entry.
Before patch readahead02 test broken,
readahead02 1 TBROK : safe_file_ops.c:144: Failed to open FILE
'/sys/dev/block/8:2/queue/read_ahead_kb' for reading at readahead02.c:197: errno=ENOENT(2): No such file or directory
After applying patch,
readahead02    0  TINFO  :  creating test file of size: 67108864
readahead02    0  TINFO  :  max readahead size is: 131072
readahead02    0  TINFO  :  read_testfile(0)
readahead02    0  TINFO  :  max readahead size is: 131072
readahead02    0  TINFO  :  read_testfile(1)
readahead02    0  TINFO  :  max readahead size is: 131072
readahead02    1  TPASS  :  expected ret success - returned value = 0
readahead02    2  TPASS  :  offset is still at 0 as expected
readahead02    0  TINFO  :  read_testfile(0) took: 1437202 usec
readahead02    0  TINFO  :  read_testfile(1) took: 1361915 usec
readahead02    0  TINFO  :  read_testfile(0) read: 67108864 bytes
readahead02    0  TINFO  :  read_testfile(1) read: 0 bytes
readahead02    3  TPASS  :  readahead saved some I/O
readahead02    0  TINFO  :  cache can hold at least: 157404 kB
readahead02    0  TINFO  :  read_testfile(0) used cache: 65332 kB
readahead02    0  TINFO  :  read_testfile(1) used cache: 65636 kB
readahead02    4  TPASS  :  using cache as expected

Quoted 8 lines

Quoted 2 lines
This doesn't seem to be true for all entries under /sys/dev/block. If I ran your patch on lvm, testcase fails:
Thanks for your findings.
I have tested on Ubuntu and Debian.
We have to refactor this test case to work on multi distribution. I have to find a machine running CentOS and debug this case.

I think it should be enough to setup LVM volume, and point LTP's TMPDIR to it to reproduce.

Quoted 23 lines


# ./readahead02
readahead02    0  TINFO  :  creating test file of size: 67108864
readahead02    1  TBROK  :  safe_file_ops.c:144: Failed to open FILE
'/sys/dev/block/253:1/../queue/read_ahead_kb' for reading at
readahead02.c:202: errno=ENOENT(2): No such file or directory
readahead02    2  TBROK  :  safe_file_ops.c:144: Remaining cases broken

# ll /sys/dev/block/253:1
lrwxrwxrwx. 1 root root 0 Sep  5 09:21 /sys/dev/block/253:1 ->
../../devices/virtual/block/dm-1

# ll /sys/dev/block/253:1/
total 0

(quoted diff) +0 -2

-r--r--r--. 1 root root 4096 Sep  5 09:25 alignment_offset
-rw-r--r--. 1 root root 4096 Sep  5 09:25 badblocks

lrwxrwxrwx. 1 root root 0 Sep 5 09:21 bdi -> ../../bdi/253:1

(quoted diff) +0 -3

-r--r--r--. 1 root root 4096 Sep  5 09:25 capability
-r--r--r--. 1 root root 4096 Sep  5 09:25 dev
-r--r--r--. 1 root root 4096 Sep  5 09:25 discard_alignment

drwxr-xr-x. 2 root root 0 Sep 5 09:25 dm
-r--r--r--. 1 root root 4096 Sep 5 09:25 ext_range

Quoted 8 lines

Quoted 5 lines
drwxr-xr-x. 2 root root    0 Sep  5 09:25 holders
-r--r--r--. 1 root root 4096 Sep  5 09:25 inflight
drwxr-xr-x. 2 root root    0 Sep  5 09:25 integrity
drwxr-xr-x. 2 root root    0 Sep  5 09:25 power
drwxr-xr-x. 2 root root    0 Sep  5 09:25 queue
read_ahead_kb file should present in queue folder. Is this test case pass on this machine *without* my patch ?

Yes, it does pass without the patch. Since there doesn't seem to be a reliable pattern depending on value of $min number, I'm thinking we should try both and take first present:
/sys/dev/block/$maj:$min/queue/read_ahead_kb /sys/dev/block/$maj:$min/../queue/read_ahead_kb

Quoted 14 lines

/sys/dev/block/253:1/queue/read_ahead_kb
Quoted 11 lines
(quoted diff) +0 -4
-r--r--r--. 1 root root 4096 Sep  5 09:25 range
-r--r--r--. 1 root root 4096 Sep  5 09:25 removable
-r--r--r--. 1 root root 4096 Sep  5 09:25 ro
-r--r--r--. 1 root root 4096 Sep  5 09:25 size
drwxr-xr-x. 2 root root    0 Sep  5 09:25 slaves
-r--r--r--. 1 root root 4096 Sep  5 09:25 stat
lrwxrwxrwx. 1 root root    0 Sep  5 09:21 subsystem ->
../../../../class/block
drwxr-xr-x. 2 root root 0 Sep 5 09:25 trace
-rw-r--r--. 1 root root 4096 Sep 5 09:25 uevent

Quoted 10 lines

Quoted 7 lines

# lsblk
NAME                        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda                         252:0    0   35G  0 disk
├─vda1                      252:1    0  500M  0 part /boot
└─vda2                      252:2    0 34.5G  0 part
  ├─rhel_dhcp--27--118-swap 253:0    0    2G  0 lvm  [SWAP]
  └─rhel_dhcp--27--118-root 253:1    0 32.5G  0 lvm  /

Is it a physical drive or Virtual drive ?
In general I use vda for KVM.

It's virtual, from host point of view it's a qcow2 file.

Regards,
Jan

Quoted 14 lines

Quoted 4 lines
# uname -r
4.7.0-rc7+
Thank you.
Best regards
Naresh Kamboju
Quoted 3 lines
Regards,
Jan

Jan Stancek

2016-09-13 13:56 UTC #4 lore raw

PATCH v2 1/1 readahead02: fix read_ahead_kb file not found

----- Original Message -----

Quoted 11 lines

From: "Jan Stancek" <[email protected]>
To: "Naresh Kamboju" <[email protected]>
Cc: "graeme gregory" <[email protected]>, "milosz wasilewski" <[email protected]>, [email protected], "fengguang wu" <[email protected]>, [email protected]
Sent: Tuesday, 6 September, 2016 4:22:00 PM
Subject: Re: [LTP] [v2] readahead02: fix read_ahead_kb file not found

Quoted 32 lines

----- Original Message -----
Quoted 31 lines
From: "Naresh Kamboju" <[email protected]>
To: "Jan Stancek" <[email protected]>
Cc: "chrubis" <[email protected]>, [email protected], [email protected], "fengguang wu" <[email protected]>, "graeme gregory" <[email protected]>, "milosz wasilewski"
<[email protected]>
Sent: Tuesday, 6 September, 2016 2:33:58 PM
Subject: Re: [LTP] [v2] readahead02: fix read_ahead_kb file not found
Hi Jan,
Quoted 18 lines · Jan Stancek
----- Original Message -----
Quoted 15 lines
From: "naresh kamboju" <[email protected]>
To: [email protected], [email protected]
Cc: [email protected], "fengguang wu" <[email protected]>, "graeme gregory" <[email protected]>,
"milosz wasilewski" <[email protected]>
Sent: Friday, 2 September, 2016 12:42:33 PM
Subject: [LTP] [v2] readahead02: fix read_ahead_kb file not found
From: Naresh Kamboju <[email protected]>
Test case is looking for read_ahead_kb file on a partition device (8:2) and
not on block device (8:0/8:16/8:32/8:48). The appropriate block device that
holds the partition can be found at queue/read_ahead_kb entry.

Just fyi, there is a patch proposed to change this limit again:
https://lkml.org/lkml/2016/7/25/308

Regards,
Jan