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lib/stackdepot: rename hash table constants and variables
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Give more meaningful names to hash table-related constants and variables:

1. Rename STACK_HASH_SCALE to STACK_TABLE_SCALE to point out that it is
   related to scaling the hash table.

2. Rename STACK_HASH_ORDER_MIN/MAX to STACK_BUCKET_NUMBER_ORDER_MIN/MAX
   to point out that it is related to the number of hash table buckets.

3. Rename stack_hash_order to stack_bucket_number_order for the same
   reason as #2.

No functional changes.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
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xairy committed Jan 30, 2023
1 parent 4ed1d08 commit 5456286
Showing 1 changed file with 21 additions and 21 deletions.
42 changes: 21 additions & 21 deletions lib/stackdepot.c
Original file line number Diff line number Diff line change
Expand Up @@ -76,17 +76,17 @@ static bool __stack_depot_early_init_requested __initdata = IS_ENABLED(CONFIG_ST
static bool __stack_depot_early_init_passed __initdata;

/* Use one hash table bucket per 16 KB of memory. */
#define STACK_HASH_SCALE 14
#define STACK_TABLE_SCALE 14
/* Limit the number of buckets between 4K and 1M. */
#define STACK_HASH_ORDER_MIN 12
#define STACK_HASH_ORDER_MAX 20
#define STACK_BUCKET_NUMBER_ORDER_MIN 12
#define STACK_BUCKET_NUMBER_ORDER_MAX 20
/* Initial seed for jhash2. */
#define STACK_HASH_SEED 0x9747b28c

/* Hash table of pointers to stored stack traces. */
static struct stack_record **stack_table;
/* Fixed order of the number of table buckets. Used when KASAN is enabled. */
static unsigned int stack_hash_order;
static unsigned int stack_bucket_number_order;
/* Hash mask for indexing the table. */
static unsigned int stack_hash_mask;

Expand Down Expand Up @@ -137,28 +137,28 @@ int __init stack_depot_early_init(void)
* in fuzzing scenarios, which leads to a large number of different
* stack traces being stored in stack depot.
*/
if (kasan_enabled() && !stack_hash_order)
stack_hash_order = STACK_HASH_ORDER_MAX;
if (kasan_enabled() && !stack_bucket_number_order)
stack_bucket_number_order = STACK_BUCKET_NUMBER_ORDER_MAX;

if (!__stack_depot_early_init_requested || stack_depot_disabled)
return 0;

/*
* If stack_hash_order is not set, leave entries as 0 to rely on the
* automatic calculations performed by alloc_large_system_hash.
* If stack_bucket_number_order is not set, leave entries as 0 to rely
* on the automatic calculations performed by alloc_large_system_hash.
*/
if (stack_hash_order)
entries = 1UL << stack_hash_order;
if (stack_bucket_number_order)
entries = 1UL << stack_bucket_number_order;
pr_info("allocating hash table via alloc_large_system_hash\n");
stack_table = alloc_large_system_hash("stackdepot",
sizeof(struct stack_record *),
entries,
STACK_HASH_SCALE,
STACK_TABLE_SCALE,
HASH_EARLY | HASH_ZERO,
NULL,
&stack_hash_mask,
1UL << STACK_HASH_ORDER_MIN,
1UL << STACK_HASH_ORDER_MAX);
1UL << STACK_BUCKET_NUMBER_ORDER_MIN,
1UL << STACK_BUCKET_NUMBER_ORDER_MAX);
if (!stack_table) {
pr_err("hash table allocation failed, disabling\n");
stack_depot_disabled = true;
Expand All @@ -181,13 +181,13 @@ int stack_depot_init(void)
goto out_unlock;

/*
* Similarly to stack_depot_early_init, use stack_hash_order
* Similarly to stack_depot_early_init, use stack_bucket_number_order
* if assigned, and rely on automatic scaling otherwise.
*/
if (stack_hash_order) {
entries = 1UL << stack_hash_order;
if (stack_bucket_number_order) {
entries = 1UL << stack_bucket_number_order;
} else {
int scale = STACK_HASH_SCALE;
int scale = STACK_TABLE_SCALE;

entries = nr_free_buffer_pages();
entries = roundup_pow_of_two(entries);
Expand All @@ -198,10 +198,10 @@ int stack_depot_init(void)
entries <<= (PAGE_SHIFT - scale);
}

if (entries < 1UL << STACK_HASH_ORDER_MIN)
entries = 1UL << STACK_HASH_ORDER_MIN;
if (entries > 1UL << STACK_HASH_ORDER_MAX)
entries = 1UL << STACK_HASH_ORDER_MAX;
if (entries < 1UL << STACK_BUCKET_NUMBER_ORDER_MIN)
entries = 1UL << STACK_BUCKET_NUMBER_ORDER_MIN;
if (entries > 1UL << STACK_BUCKET_NUMBER_ORDER_MAX)
entries = 1UL << STACK_BUCKET_NUMBER_ORDER_MAX;

pr_info("allocating hash table of %lu entries via kvcalloc\n", entries);
stack_table = kvcalloc(entries, sizeof(struct stack_record *), GFP_KERNEL);
Expand Down

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