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* [PATCH v2 00/18] Increase maximum number of Infiniband HCAs per system
@ 2010-02-02 19:07 ` Alex Chiang
  0 siblings, 0 replies; 33+ messages in thread
From: Alex Chiang @ 2010-02-02 19:07 UTC (permalink / raw)
  To: rdreier-FYB4Gu1CFyUAvxtiuMwx3w
  Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA, justin.chen-VXdhtT5mjnY,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA

This is v2 of a patch series that increases the maximum number of
IB HCAs supported per system.

The original mail thread is here:
	http://lkml.org/lkml/2010/1/29/346

One note, I decided to "copy/paste" since factoring out the overflow
code in the three drivers seemed like overkill. If so desired, I could
factor those three separate functions into something provided by the
core, but that seemed like more trouble than it was worth at the time.

As before, I still don't have access to a giant system, so what I did
to test was to stick 4 cards into a small system, and then modify the
limits with debug patches similar to this:

diff --git a/drivers/infiniband/core/ucm.c b/drivers/infiniband/core/ucm.c
index 7bf0a82..8581e64 100644
--- a/drivers/infiniband/core/ucm.c
+++ b/drivers/infiniband/core/ucm.c
@@ -102,7 +102,7 @@ struct ib_ucm_event {
 enum {
        IB_UCM_MAJOR = 231,
        IB_UCM_BASE_MINOR = 224,
-       IB_UCM_MAX_DEVICES = 32
+       IB_UCM_MAX_DEVICES = 2
 };


I tested all 3 drivers this way (uverbs, umad, ucm). I verified that
we're not leaking device numbers on multiple modprobe/rmmod cycles,
that there aren't any funny interactions when various combinations of
the drivers are loaded.

I did not test the rest of the OFED stack. I did write some trivial
programs to open the devices in /dev and close them again.

Here's an example of some of the testing:

	dl585g2:~ # modprobe ib_uverbs
	dl585g2:~ # modprobe ib_umad
	dl585g2:~ # modprobe ib_ucm
	dl585g2:~ # ls -l /dev/uverb*
	crw-rw---- 1 root root 231, 192 Feb  2 05:55 /dev/uverbs0
	crw-rw---- 1 root root 231, 193 Feb  2 05:55 /dev/uverbs1
	crw-rw---- 1 root root 249,   0 Feb  2 05:55 /dev/uverbs2
	crw-rw---- 1 root root 249,   1 Feb  2 05:55 /dev/uverbs3
	dl585g2:~ # ls -l /dev/umad*
	crw-rw---- 1 root root 231, 0 Feb  2 05:55 /dev/umad0
	crw-rw---- 1 root root 231, 1 Feb  2 05:55 /dev/umad1
	crw-rw---- 1 root root 231, 2 Feb  2 05:55 /dev/umad2
	crw-rw---- 1 root root 231, 3 Feb  2 05:55 /dev/umad3
	crw-rw---- 1 root root 248, 0 Feb  2 05:55 /dev/umad4
	crw-rw---- 1 root root 248, 1 Feb  2 05:55 /dev/umad5
	crw-rw---- 1 root root 248, 2 Feb  2 05:55 /dev/umad6
	crw-rw---- 1 root root 248, 3 Feb  2 05:55 /dev/umad7
	dl585g2:~ # ls -l /dev/issm*
	crw-rw---- 1 root root 231, 4 Feb  2 05:55 /dev/issm0
	crw-rw---- 1 root root 231, 5 Feb  2 05:55 /dev/issm1
	crw-rw---- 1 root root 231, 6 Feb  2 05:55 /dev/issm2
	crw-rw---- 1 root root 231, 7 Feb  2 05:55 /dev/issm3
	crw-rw---- 1 root root 248, 4 Feb  2 05:55 /dev/issm4
	crw-rw---- 1 root root 248, 5 Feb  2 05:55 /dev/issm5
	crw-rw---- 1 root root 248, 6 Feb  2 05:55 /dev/issm6
	crw-rw---- 1 root root 248, 7 Feb  2 05:55 /dev/issm7
	dl585g2:~ # ls -l /dev/ucm*
	crw-rw---- 1 root root 231, 224 Feb  2 05:55 /dev/ucm0
	crw-rw---- 1 root root 231, 225 Feb  2 05:55 /dev/ucm1
	crw-rw---- 1 root root 247,   0 Feb  2 05:55 /dev/ucm2
	crw-rw---- 1 root root 247,   1 Feb  2 05:55 /dev/ucm3

Note that the major and minor numbers are behaving rather sanely.

	dl585g2:~ # rmmod ib_ucm
	dl585g2:~ # rmmod ib_uverbs
	dl585g2:~ # rmmod ib_umad

Reset.

	dl585g2:~ # modprobe ib_ucm
	dl585g2:~ # ls -l /dev/ucm*
	crw-rw---- 1 root root 231, 224 Feb  2 05:57 /dev/ucm0
	crw-rw---- 1 root root 231, 225 Feb  2 05:57 /dev/ucm1
	crw-rw---- 1 root root 248,   0 Feb  2 05:57 /dev/ucm2
	crw-rw---- 1 root root 248,   1 Feb  2 05:57 /dev/ucm3

See that /dev/ucm* devices now have a different major number 
compared to last time(248 vs 247), since we loaded that driver first.

But wait, why is it 248 and not 249? Is there a leak somewhere?

	dl585g2:~ # ls -l /dev/uverb*
	crw-rw---- 1 root root 231, 192 Feb  2 05:57 /dev/uverbs0
	crw-rw---- 1 root root 231, 193 Feb  2 05:57 /dev/uverbs1
	crw-rw---- 1 root root 249,   0 Feb  2 05:57 /dev/uverbs2
	crw-rw---- 1 root root 249,   1 Feb  2 05:57 /dev/uverbs3
	dl585g2:~ # rmmod ib_uverbs
	ERROR: Module ib_uverbs is in use by ib_ucm

Ah, ib_ucm is dependent on ib_uverbs, so when we modprobed ib_ucm,
in reality ib_uverbs got loaded first. See how it has a higher
major number.

	dl585g2:~ # rmmod ib_ucm
	dl585g2:~ # rmmod ib_uverbs
	dl585g2:~ # modprobe ib_umad
	dl585g2:~ # ls -l /dev/umad*
	crw-rw---- 1 root root 231, 0 Feb  2 05:58 /dev/umad0
	crw-rw---- 1 root root 231, 1 Feb  2 05:58 /dev/umad1
	crw-rw---- 1 root root 231, 2 Feb  2 05:58 /dev/umad2
	crw-rw---- 1 root root 231, 3 Feb  2 05:58 /dev/umad3
	crw-rw---- 1 root root 249, 0 Feb  2 05:58 /dev/umad4
	crw-rw---- 1 root root 249, 1 Feb  2 05:58 /dev/umad5
	crw-rw---- 1 root root 249, 2 Feb  2 05:58 /dev/umad6
	crw-rw---- 1 root root 249, 3 Feb  2 05:58 /dev/umad7
	dl585g2:~ # ls -l /dev/issm*
	crw-rw---- 1 root root 231, 4 Feb  2 05:58 /dev/issm0
	crw-rw---- 1 root root 231, 5 Feb  2 05:58 /dev/issm1
	crw-rw---- 1 root root 231, 6 Feb  2 05:58 /dev/issm2
	crw-rw---- 1 root root 231, 7 Feb  2 05:58 /dev/issm3
	crw-rw---- 1 root root 249, 4 Feb  2 05:58 /dev/issm4
	crw-rw---- 1 root root 249, 5 Feb  2 05:58 /dev/issm5
	crw-rw---- 1 root root 249, 6 Feb  2 05:58 /dev/issm6
	crw-rw---- 1 root root 249, 7 Feb  2 05:58 /dev/issm7

Finally, after one more reset, we see ib_umad loaded first and
obtaining the major number of 249.

v1 -> v2:
	- update umad and ucm drivers too

---

Alex Chiang (18):
      IB/uverbs: convert *cdev to cdev in struct ib_uverbs_device
      IB/uverbs: remove dev_table
      IB/uverbs: use stack variable 'devnum' in ib_uverbs_add_one
      IB/uverbs: use stack variable 'base' in ib_uverbs_add_one
      IB/uverbs: increase maximum devices supported
      IB/uverbs: pack struct ib_uverbs_event_file tighter
      IB/uverbs: whitespace cleanup
      IB/umad: convert cdev pointers to embedded structs in struct ib_umad_port
      IB/umad: remove port_table[]
      IB/umad: use stack variable 'devnum' in ib_umad_init_port
      IB/umad: use stack variable 'base' in ib_umad_init_port
      IB/umad: increase maximum devices supported
      IB/umad: clean whitespace
      IB/ucm: use stack variable 'devnum' in ib_ucm_add_one
      IB/ucm: use stack variable 'base' in ib_ucm_add_one
      IB/ucm: increase maximum devices supported
      IB/ucm: clean whitespace errors
      IB/core: pack struct ib_device a little tighter


 drivers/infiniband/core/ucm.c         |   63 ++++++++++--
 drivers/infiniband/core/user_mad.c    |  173 +++++++++++++++++----------------
 drivers/infiniband/core/uverbs.h      |   11 +-
 drivers/infiniband/core/uverbs_main.c |  175 +++++++++++++++++++--------------
 include/rdma/ib_verbs.h               |    4 -
 5 files changed, 255 insertions(+), 171 deletions(-)

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^ permalink raw reply related	[flat|nested] 33+ messages in thread

end of thread, other threads:[~2010-02-24 18:24 UTC | newest]

Thread overview: 33+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-02-02 19:07 [PATCH v2 00/18] Increase maximum number of Infiniband HCAs per system Alex Chiang
2010-02-02 19:07 ` Alex Chiang
2010-02-02 19:07 ` [PATCH v2 01/18] IB/uverbs: convert *cdev to cdev in struct ib_uverbs_device Alex Chiang
2010-02-02 19:07 ` [PATCH v2 03/18] IB/uverbs: use stack variable 'devnum' in ib_uverbs_add_one Alex Chiang
2010-02-02 19:08 ` [PATCH v2 05/18] IB/uverbs: increase maximum devices supported Alex Chiang
2010-02-02 19:08 ` [PATCH v2 08/18] IB/umad: convert cdev pointers to embedded structs in struct ib_umad_port Alex Chiang
2010-02-02 19:08 ` [PATCH v2 10/18] IB/umad: use stack variable 'devnum' in ib_umad_init_port Alex Chiang
2010-02-02 19:08 ` [PATCH v2 11/18] IB/umad: use stack variable 'base' " Alex Chiang
2010-02-02 19:08 ` [PATCH v2 12/18] IB/umad: increase maximum devices supported Alex Chiang
     [not found] ` <20100202185235.28217.64521.stgit-tBlMHHroXgg@public.gmane.org>
2010-02-02 19:07   ` [PATCH v2 02/18] IB/uverbs: remove dev_table Alex Chiang
2010-02-02 19:07     ` Alex Chiang
2010-02-02 19:08   ` [PATCH v2 04/18] IB/uverbs: use stack variable 'base' in ib_uverbs_add_one Alex Chiang
2010-02-02 19:08     ` Alex Chiang
2010-02-02 19:08   ` [PATCH v2 06/18] IB/uverbs: pack struct ib_uverbs_event_file tighter Alex Chiang
2010-02-02 19:08     ` Alex Chiang
2010-02-02 19:08   ` [PATCH v2 07/18] IB/uverbs: whitespace cleanup Alex Chiang
2010-02-02 19:08     ` Alex Chiang
2010-02-02 19:08   ` [PATCH v2 09/18] IB/umad: remove port_table[] Alex Chiang
2010-02-02 19:08     ` Alex Chiang
2010-02-02 19:08   ` [PATCH v2 13/18] IB/umad: clean whitespace Alex Chiang
2010-02-02 19:08     ` Alex Chiang
2010-02-02 19:08   ` [PATCH v2 14/18] IB/ucm: use stack variable 'devnum' in ib_ucm_add_one Alex Chiang
2010-02-02 19:08     ` Alex Chiang
2010-02-02 19:09   ` [PATCH v2 16/18] IB/ucm: increase maximum devices supported Alex Chiang
2010-02-02 19:09     ` Alex Chiang
2010-02-02 19:09   ` [PATCH v2 17/18] IB/ucm: clean whitespace errors Alex Chiang
2010-02-02 19:09     ` Alex Chiang
2010-02-02 19:09   ` [PATCH v2 18/18] IB/core: pack struct ib_device a little tighter Alex Chiang
2010-02-02 19:09     ` Alex Chiang
     [not found]     ` <20100202190916.28217.90954.stgit-tBlMHHroXgg@public.gmane.org>
2010-02-24 18:24       ` Roland Dreier
2010-02-24 18:24         ` Roland Dreier
2010-02-02 19:09 ` [PATCH v2 15/18] IB/ucm: use stack variable 'base' in ib_ucm_add_one Alex Chiang
2010-02-08 21:30 ` [PATCH v2 00/18] Increase maximum number of Infiniband HCAs per system Alex Chiang

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