From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Hi folks,
This -v2 is a updated set of miscellaneous improvements to iscsi-target
thread_set code to reduce latency for handling 100's of simultaneous
logins, that goes along with iscsi-target login multi-plexing logic
in-flight for v3.12-rc1.
The first patch fixes a long-standing race between rx/tx pre handlers
use of flush_signals(), and iscsi_deallocate_extra_thread_sets() setting
of ISCSI_THREAD_SET_DIE before calling kthread_stop().
The second patch removes the iscsi_thread_set->[rx,tx]_post_start_comp
in favor of a single ->ts_activate_sem in order to save extra context
switches for each iscsi_activate_thread_set() call. It also refactors
duplicated thread_set dellocate logic into common code.
And the third patch removes an unnecessary wait_for_completion() within
iscsi_get_thread_set(), that originally would wait an extra second when
no thread_set pair was available.
Changes for v2:
- Add explicit complete(&ts->[rx,tx]_start_comp); before kthread_stop() in
iscsi_deallocate_extra_thread_sets()
- Drop left-over send_sig() calls in iscsi_deallocate_extra_thread_sets()
- Add kthread_should_stop() check in iscsi_signal_thread_pre_handler()
- Set ISCSI_THREAD_SET_ACTIVE before calling complete in
iscsi_activate_thread_set
- Protect ts->conn sanity checks with ->ts_state_lock in
RX/TX pre handlers
- Add ->ts_activate_sem to save extra context switches per
iscsi_activate_thread_set() call
- Refactor thread_set shutdown into iscsi_deallocate_thread_one()
Thanks,
--nab
Nicholas Bellinger (3):
iscsi-target: Fix race with thread_pre_handler flush_signals +
ISCSI_THREAD_SET_DIE
iscsi-target: Add thread_set->ts_activate_sem + use common deallocate
iscsi-target: Remove unnecessary wait_for_completion in
iscsi_get_thread_set
drivers/target/iscsi/iscsi_target_tq.c | 163 +++++++++++++-------------------
drivers/target/iscsi/iscsi_target_tq.h | 5 +-
2 files changed, 68 insertions(+), 100 deletions(-)
--
1.7.2.5
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