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author | Paul E. McKenney <paulmck@kernel.org> | 2023-03-17 20:01:02 -0700 |
---|---|---|
committer | Paul E. McKenney <paulmck@kernel.org> | 2023-04-04 08:36:23 -0700 |
commit | 3b46679c623c2766f4c56fd3f9ce8edbb38c5d20 (patch) | |
tree | 4904c05df78ea85ed7c133e8ef16a60eaac41fb5 | |
parent | 03200b5ca3b4d4edf634dc052bf3b8eb8dc8bbbc (diff) | |
download | linux-stable-3b46679c623c2766f4c56fd3f9ce8edbb38c5d20.tar.gz linux-stable-3b46679c623c2766f4c56fd3f9ce8edbb38c5d20.tar.bz2 linux-stable-3b46679c623c2766f4c56fd3f9ce8edbb38c5d20.zip |
srcu: Move heuristics fields from srcu_struct to srcu_usage
This commit moves the ->srcu_size_jiffies, ->srcu_n_lock_retries,
and ->srcu_n_exp_nodelay fields from the srcu_struct structure to the
srcu_usage structure to reduce the size of the former in order to improve
cache locality.
Suggested-by: Christoph Hellwig <hch@lst.de>
Tested-by: Sachin Sant <sachinp@linux.ibm.com>
Tested-by: "Zhang, Qiang1" <qiang1.zhang@intel.com>
Tested-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
-rw-r--r-- | include/linux/srcutree.h | 6 | ||||
-rw-r--r-- | kernel/rcu/srcutree.c | 18 |
2 files changed, 12 insertions, 12 deletions
diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h index 372e35b0e8b6..3023492d8d89 100644 --- a/include/linux/srcutree.h +++ b/include/linux/srcutree.h @@ -73,6 +73,9 @@ struct srcu_usage { unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ unsigned long srcu_gp_start; /* Last GP start timestamp (jiffies) */ unsigned long srcu_last_gp_end; /* Last GP end timestamp (ns) */ + unsigned long srcu_size_jiffies; /* Current contention-measurement interval. */ + unsigned long srcu_n_lock_retries; /* Contention events in current interval. */ + unsigned long srcu_n_exp_nodelay; /* # expedited no-delays in current GP phase. */ }; /* @@ -80,9 +83,6 @@ struct srcu_usage { */ struct srcu_struct { unsigned int srcu_idx; /* Current rdr array element. */ - unsigned long srcu_size_jiffies; /* Current contention-measurement interval. */ - unsigned long srcu_n_lock_retries; /* Contention events in current interval. */ - unsigned long srcu_n_exp_nodelay; /* # expedited no-delays in current GP phase. */ struct srcu_data __percpu *sda; /* Per-CPU srcu_data array. */ bool sda_is_static; /* May ->sda be passed to free_percpu()? */ unsigned long srcu_barrier_seq; /* srcu_barrier seq #. */ diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 340eb685cf64..291fb520bce0 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -348,11 +348,11 @@ static void spin_lock_irqsave_check_contention(struct srcu_struct *ssp) if (!SRCU_SIZING_IS_CONTEND() || ssp->srcu_sup->srcu_size_state) return; j = jiffies; - if (ssp->srcu_size_jiffies != j) { - ssp->srcu_size_jiffies = j; - ssp->srcu_n_lock_retries = 0; + if (ssp->srcu_sup->srcu_size_jiffies != j) { + ssp->srcu_sup->srcu_size_jiffies = j; + ssp->srcu_sup->srcu_n_lock_retries = 0; } - if (++ssp->srcu_n_lock_retries <= small_contention_lim) + if (++ssp->srcu_sup->srcu_n_lock_retries <= small_contention_lim) return; __srcu_transition_to_big(ssp); } @@ -624,8 +624,8 @@ static unsigned long srcu_get_delay(struct srcu_struct *ssp) if (time_after(j, gpstart)) jbase += j - gpstart; if (!jbase) { - WRITE_ONCE(ssp->srcu_n_exp_nodelay, READ_ONCE(ssp->srcu_n_exp_nodelay) + 1); - if (READ_ONCE(ssp->srcu_n_exp_nodelay) > srcu_max_nodelay_phase) + WRITE_ONCE(ssp->srcu_sup->srcu_n_exp_nodelay, READ_ONCE(ssp->srcu_sup->srcu_n_exp_nodelay) + 1); + if (READ_ONCE(ssp->srcu_sup->srcu_n_exp_nodelay) > srcu_max_nodelay_phase) jbase = 1; } } @@ -783,7 +783,7 @@ static void srcu_gp_start(struct srcu_struct *ssp) rcu_seq_snap(&ssp->srcu_sup->srcu_gp_seq)); spin_unlock_rcu_node(sdp); /* Interrupts remain disabled. */ WRITE_ONCE(ssp->srcu_sup->srcu_gp_start, jiffies); - WRITE_ONCE(ssp->srcu_n_exp_nodelay, 0); + WRITE_ONCE(ssp->srcu_sup->srcu_n_exp_nodelay, 0); smp_mb(); /* Order prior store to ->srcu_gp_seq_needed vs. GP start. */ rcu_seq_start(&ssp->srcu_sup->srcu_gp_seq); state = rcu_seq_state(ssp->srcu_sup->srcu_gp_seq); @@ -1625,7 +1625,7 @@ static void srcu_advance_state(struct srcu_struct *ssp) srcu_flip(ssp); spin_lock_irq_rcu_node(ssp->srcu_sup); rcu_seq_set_state(&ssp->srcu_sup->srcu_gp_seq, SRCU_STATE_SCAN2); - ssp->srcu_n_exp_nodelay = 0; + ssp->srcu_sup->srcu_n_exp_nodelay = 0; spin_unlock_irq_rcu_node(ssp->srcu_sup); } @@ -1640,7 +1640,7 @@ static void srcu_advance_state(struct srcu_struct *ssp) mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex); return; /* readers present, retry later. */ } - ssp->srcu_n_exp_nodelay = 0; + ssp->srcu_sup->srcu_n_exp_nodelay = 0; srcu_gp_end(ssp); /* Releases ->srcu_gp_mutex. */ } } |