From 08f87f769b595151be1afeff53e144f543faa614 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 06 Dec 2023 09:51:13 +0000
Subject: [PATCH] add dts config
---
kernel/lib/sbitmap.c | 207 +++++++++++++++++++++++++++++++++++++++------------
1 files changed, 159 insertions(+), 48 deletions(-)
diff --git a/kernel/lib/sbitmap.c b/kernel/lib/sbitmap.c
index 0572ac3..267aa77 100644
--- a/kernel/lib/sbitmap.c
+++ b/kernel/lib/sbitmap.c
@@ -1,24 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2016 Facebook
* Copyright (C) 2013-2014 Jens Axboe
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License v2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <linux/sched.h>
#include <linux/random.h>
#include <linux/sbitmap.h>
#include <linux/seq_file.h>
+
+/*
+ * See if we have deferred clears that we can batch move
+ */
+static inline bool sbitmap_deferred_clear(struct sbitmap *sb, int index)
+{
+ unsigned long mask, val;
+ bool ret = false;
+ unsigned long flags;
+
+ spin_lock_irqsave(&sb->map[index].swap_lock, flags);
+
+ if (!sb->map[index].cleared)
+ goto out_unlock;
+
+ /*
+ * First get a stable cleared mask, setting the old mask to 0.
+ */
+ mask = xchg(&sb->map[index].cleared, 0);
+
+ /*
+ * Now clear the masked bits in our free word
+ */
+ do {
+ val = sb->map[index].word;
+ } while (cmpxchg(&sb->map[index].word, val, val & ~mask) != val);
+
+ ret = true;
+out_unlock:
+ spin_unlock_irqrestore(&sb->map[index].swap_lock, flags);
+ return ret;
+}
int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift,
gfp_t flags, int node)
@@ -59,6 +80,7 @@
for (i = 0; i < sb->map_nr; i++) {
sb->map[i].depth = min(depth, bits_per_word);
depth -= sb->map[i].depth;
+ spin_lock_init(&sb->map[i].swap_lock);
}
return 0;
}
@@ -68,6 +90,9 @@
{
unsigned int bits_per_word = 1U << sb->shift;
unsigned int i;
+
+ for (i = 0; i < sb->map_nr; i++)
+ sbitmap_deferred_clear(sb, i);
sb->depth = depth;
sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word);
@@ -111,6 +136,24 @@
return nr;
}
+static int sbitmap_find_bit_in_index(struct sbitmap *sb, int index,
+ unsigned int alloc_hint, bool round_robin)
+{
+ int nr;
+
+ do {
+ nr = __sbitmap_get_word(&sb->map[index].word,
+ sb->map[index].depth, alloc_hint,
+ !round_robin);
+ if (nr != -1)
+ break;
+ if (!sbitmap_deferred_clear(sb, index))
+ break;
+ } while (1);
+
+ return nr;
+}
+
int sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint, bool round_robin)
{
unsigned int i, index;
@@ -118,24 +161,28 @@
index = SB_NR_TO_INDEX(sb, alloc_hint);
+ /*
+ * Unless we're doing round robin tag allocation, just use the
+ * alloc_hint to find the right word index. No point in looping
+ * twice in find_next_zero_bit() for that case.
+ */
+ if (round_robin)
+ alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
+ else
+ alloc_hint = 0;
+
for (i = 0; i < sb->map_nr; i++) {
- nr = __sbitmap_get_word(&sb->map[index].word,
- sb->map[index].depth,
- SB_NR_TO_BIT(sb, alloc_hint),
- !round_robin);
+ nr = sbitmap_find_bit_in_index(sb, index, alloc_hint,
+ round_robin);
if (nr != -1) {
nr += index << sb->shift;
break;
}
/* Jump to next index. */
- index++;
- alloc_hint = index << sb->shift;
-
- if (index >= sb->map_nr) {
+ alloc_hint = 0;
+ if (++index >= sb->map_nr)
index = 0;
- alloc_hint = 0;
- }
}
return nr;
@@ -151,6 +198,7 @@
index = SB_NR_TO_INDEX(sb, alloc_hint);
for (i = 0; i < sb->map_nr; i++) {
+again:
nr = __sbitmap_get_word(&sb->map[index].word,
min(sb->map[index].depth, shallow_depth),
SB_NR_TO_BIT(sb, alloc_hint), true);
@@ -158,6 +206,9 @@
nr += index << sb->shift;
break;
}
+
+ if (sbitmap_deferred_clear(sb, index))
+ goto again;
/* Jump to next index. */
index++;
@@ -178,46 +229,43 @@
unsigned int i;
for (i = 0; i < sb->map_nr; i++) {
- if (sb->map[i].word)
+ if (sb->map[i].word & ~sb->map[i].cleared)
return true;
}
return false;
}
EXPORT_SYMBOL_GPL(sbitmap_any_bit_set);
-bool sbitmap_any_bit_clear(const struct sbitmap *sb)
-{
- unsigned int i;
-
- for (i = 0; i < sb->map_nr; i++) {
- const struct sbitmap_word *word = &sb->map[i];
- unsigned long ret;
-
- ret = find_first_zero_bit(&word->word, word->depth);
- if (ret < word->depth)
- return true;
- }
- return false;
-}
-EXPORT_SYMBOL_GPL(sbitmap_any_bit_clear);
-
-unsigned int sbitmap_weight(const struct sbitmap *sb)
+static unsigned int __sbitmap_weight(const struct sbitmap *sb, bool set)
{
unsigned int i, weight = 0;
for (i = 0; i < sb->map_nr; i++) {
const struct sbitmap_word *word = &sb->map[i];
- weight += bitmap_weight(&word->word, word->depth);
+ if (set)
+ weight += bitmap_weight(&word->word, word->depth);
+ else
+ weight += bitmap_weight(&word->cleared, word->depth);
}
return weight;
}
-EXPORT_SYMBOL_GPL(sbitmap_weight);
+
+static unsigned int sbitmap_weight(const struct sbitmap *sb)
+{
+ return __sbitmap_weight(sb, true);
+}
+
+static unsigned int sbitmap_cleared(const struct sbitmap *sb)
+{
+ return __sbitmap_weight(sb, false);
+}
void sbitmap_show(struct sbitmap *sb, struct seq_file *m)
{
seq_printf(m, "depth=%u\n", sb->depth);
- seq_printf(m, "busy=%u\n", sbitmap_weight(sb));
+ seq_printf(m, "busy=%u\n", sbitmap_weight(sb) - sbitmap_cleared(sb));
+ seq_printf(m, "cleared=%u\n", sbitmap_cleared(sb));
seq_printf(m, "bits_per_word=%u\n", 1U << sb->shift);
seq_printf(m, "map_nr=%u\n", sb->map_nr);
}
@@ -244,7 +292,10 @@
for (i = 0; i < sb->map_nr; i++) {
unsigned long word = READ_ONCE(sb->map[i].word);
+ unsigned long cleared = READ_ONCE(sb->map[i].cleared);
unsigned int word_bits = READ_ONCE(sb->map[i].depth);
+
+ word &= ~cleared;
while (word_bits > 0) {
unsigned int bits = min(8 - byte_bits, word_bits);
@@ -325,6 +376,7 @@
sbq->min_shallow_depth = UINT_MAX;
sbq->wake_batch = sbq_calc_wake_batch(sbq, depth);
atomic_set(&sbq->wake_index, 0);
+ atomic_set(&sbq->ws_active, 0);
sbq->ws = kzalloc_node(SBQ_WAIT_QUEUES * sizeof(*sbq->ws), flags, node);
if (!sbq->ws) {
@@ -440,15 +492,16 @@
{
int i, wake_index;
+ if (!atomic_read(&sbq->ws_active))
+ return NULL;
+
wake_index = atomic_read(&sbq->wake_index);
for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
struct sbq_wait_state *ws = &sbq->ws[wake_index];
if (waitqueue_active(&ws->wait)) {
- int o = atomic_read(&sbq->wake_index);
-
- if (wake_index != o)
- atomic_cmpxchg(&sbq->wake_index, o, wake_index);
+ if (wake_index != atomic_read(&sbq->wake_index))
+ atomic_set(&sbq->wake_index, wake_index);
return ws;
}
@@ -509,7 +562,19 @@
void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr,
unsigned int cpu)
{
- sbitmap_clear_bit_unlock(&sbq->sb, nr);
+ /*
+ * Once the clear bit is set, the bit may be allocated out.
+ *
+ * Orders READ/WRITE on the asssociated instance(such as request
+ * of blk_mq) by this bit for avoiding race with re-allocation,
+ * and its pair is the memory barrier implied in __sbitmap_get_word.
+ *
+ * One invariant is that the clear bit has to be zero when the bit
+ * is in use.
+ */
+ smp_mb__before_atomic();
+ sbitmap_deferred_clear_bit(&sbq->sb, nr);
+
/*
* Pairs with the memory barrier in set_current_state() to ensure the
* proper ordering of clear_bit_unlock()/waitqueue_active() in the waker
@@ -564,6 +629,7 @@
seq_printf(m, "wake_batch=%u\n", sbq->wake_batch);
seq_printf(m, "wake_index=%d\n", atomic_read(&sbq->wake_index));
+ seq_printf(m, "ws_active=%d\n", atomic_read(&sbq->ws_active));
seq_puts(m, "ws={\n");
for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
@@ -579,3 +645,48 @@
seq_printf(m, "min_shallow_depth=%u\n", sbq->min_shallow_depth);
}
EXPORT_SYMBOL_GPL(sbitmap_queue_show);
+
+void sbitmap_add_wait_queue(struct sbitmap_queue *sbq,
+ struct sbq_wait_state *ws,
+ struct sbq_wait *sbq_wait)
+{
+ if (!sbq_wait->sbq) {
+ sbq_wait->sbq = sbq;
+ atomic_inc(&sbq->ws_active);
+ add_wait_queue(&ws->wait, &sbq_wait->wait);
+ }
+}
+EXPORT_SYMBOL_GPL(sbitmap_add_wait_queue);
+
+void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait)
+{
+ list_del_init(&sbq_wait->wait.entry);
+ if (sbq_wait->sbq) {
+ atomic_dec(&sbq_wait->sbq->ws_active);
+ sbq_wait->sbq = NULL;
+ }
+}
+EXPORT_SYMBOL_GPL(sbitmap_del_wait_queue);
+
+void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq,
+ struct sbq_wait_state *ws,
+ struct sbq_wait *sbq_wait, int state)
+{
+ if (!sbq_wait->sbq) {
+ atomic_inc(&sbq->ws_active);
+ sbq_wait->sbq = sbq;
+ }
+ prepare_to_wait_exclusive(&ws->wait, &sbq_wait->wait, state);
+}
+EXPORT_SYMBOL_GPL(sbitmap_prepare_to_wait);
+
+void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws,
+ struct sbq_wait *sbq_wait)
+{
+ finish_wait(&ws->wait, &sbq_wait->wait);
+ if (sbq_wait->sbq) {
+ atomic_dec(&sbq->ws_active);
+ sbq_wait->sbq = NULL;
+ }
+}
+EXPORT_SYMBOL_GPL(sbitmap_finish_wait);
--
Gitblit v1.6.2