From dee70735c5e8db7978f0e5b40535598574390c67 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Sat, 2 Oct 2010 15:28:33 +0000 Subject: [PATCH] ib_srpt: Added a note about unloading while I/O is ongoing. git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@2338 d57e44dd-8a1f-0410-8b47-8ef2f437770f --- srpt/README | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/srpt/README b/srpt/README index 924f18110..a89d90036 100644 --- a/srpt/README +++ b/srpt/README @@ -180,6 +180,19 @@ For more information, see also: * http://www.linux-ha.org/wiki/Main_Page +Notes about ib_srpt +------------------- + +* Unloading the kernel module ib_srpt while I/O is ongoing is supported. + However, it can take up to two minutes before unloading finishes. During + that time CPU usage will be high. This can happen because sometimes it + happens that ib_srpt resets the InfiniBand queue pair used for communication + with the SRP initiator but the Linux InfiniBand stack does not deliver a + completion notification for every aborted IB work request to ib_srpt. + ib_srpt then waits until the SCST core calls the ib_srpt timeout handler + for pending SCSI commands, which can take up to 2 * max_hw_pending_time. + + Performance Notes - Initiator Side ----------------------------------