diff options
| author | Nicholas Bellinger <nab@linux-iscsi.org> | 2013-02-27 17:53:52 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-14 11:26:11 -0700 |
| commit | f8d5ba6c2562b423d072cf66b7c8ae09c239a728 (patch) | |
| tree | 8d46a55bf94563a2cc9f8fcac67327d5d676bea8 | |
| parent | 50909650d88133e2231cf43632d2f4ee76266fd1 (diff) | |
iscsi-target: Fix immediate queue starvation regression with DATAIN
commit fd3a9025c0349bc9b01d627529f54e6e1e389015 upstream.
This patch addresses a v3.5+ regression in iscsi-target where TX thread
process context -> handle_response_queue() execution is allowed to run
unbounded while servicing constant outgoing flow of ISTATE_SEND_DATAIN
response state.
This ends up preventing memory release of StatSN acknowledged commands
in a timely manner when under heavy large block streaming DATAIN
workloads.
The regression bug was initially introduced with:
commit 6f3c0e69a9c20441bdc6d3b2d18b83b244384ec6
Author: Andy Grover <agrover@redhat.com>
Date: Tue Apr 3 15:51:09 2012 -0700
target/iscsi: Refactor target_tx_thread immediate+response queue loops
Go ahead and follow original iscsi_target_tx_thread() logic and check
to break for immediate queue processing after each DataIN Sequence and/or
Response PDU has been sent.
Reported-by: Benjamin ESTRABAUD <be@mpstor.com>
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/target/iscsi/iscsi_target.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index 339f97f7085b..42a2bf759d8f 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -3570,6 +3570,10 @@ check_rsp_state: spin_lock_bh(&cmd->istate_lock); cmd->i_state = ISTATE_SENT_STATUS; spin_unlock_bh(&cmd->istate_lock); + + if (atomic_read(&conn->check_immediate_queue)) + return 1; + continue; } else if (ret == 2) { /* Still must send status, @@ -3659,7 +3663,7 @@ check_rsp_state: } if (atomic_read(&conn->check_immediate_queue)) - break; + return 1; } return 0; @@ -3703,12 +3707,15 @@ restart: signal_pending(current)) goto transport_err; +get_immediate: ret = handle_immediate_queue(conn); if (ret < 0) goto transport_err; ret = handle_response_queue(conn); - if (ret == -EAGAIN) + if (ret == 1) + goto get_immediate; + else if (ret == -EAGAIN) goto restart; else if (ret < 0) goto transport_err; |