diff options
| author | Matt Fleming <mfleming@cloudflare.com> | 2025-07-18 16:39:28 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-08-02 12:01:38 -0700 |
| commit | ed4f142f72a9191b8236778093074c277435bf8a (patch) | |
| tree | 6e2ee493ddd2295eb32886efdd6924d60a196f03 /lib/stackdepot.c | |
| parent | 6c6d8f8ba7789c221a2e4c43a0ed982c7a41f428 (diff) | |
| download | net-next-ed4f142f72a9191b8236778093074c277435bf8a.tar.gz | |
stackdepot: make max number of pools boot-time configurable
We're hitting the WARN in depot_init_pool() about reaching the stack depot
limit because we have long stacks that don't dedup very well.
Introduce a new start-up parameter to allow users to set the number of
maximum stack depot pools.
Link: https://lkml.kernel.org/r/20250718153928.94229-1-matt@readmodwrite.com
Signed-off-by: Matt Fleming <mfleming@cloudflare.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib/stackdepot.c')
| -rw-r--r-- | lib/stackdepot.c | 67 |
1 files changed, 58 insertions, 9 deletions
diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 73d7b50924ef60..de0b0025af2b94 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -36,11 +36,11 @@ #include <linux/memblock.h> #include <linux/kasan-enabled.h> -#define DEPOT_POOLS_CAP 8192 -/* The pool_index is offset by 1 so the first record does not have a 0 handle. */ -#define DEPOT_MAX_POOLS \ - (((1LL << (DEPOT_POOL_INDEX_BITS)) - 1 < DEPOT_POOLS_CAP) ? \ - (1LL << (DEPOT_POOL_INDEX_BITS)) - 1 : DEPOT_POOLS_CAP) +/* + * The pool_index is offset by 1 so the first record does not have a 0 handle. + */ +static unsigned int stack_max_pools __read_mostly = + MIN((1LL << DEPOT_POOL_INDEX_BITS) - 1, 8192); static bool stack_depot_disabled; static bool __stack_depot_early_init_requested __initdata = IS_ENABLED(CONFIG_STACKDEPOT_ALWAYS_INIT); @@ -62,7 +62,7 @@ static unsigned int stack_bucket_number_order; static unsigned int stack_hash_mask; /* Array of memory regions that store stack records. */ -static void *stack_pools[DEPOT_MAX_POOLS]; +static void **stack_pools; /* Newly allocated pool that is not yet added to stack_pools. */ static void *new_pool; /* Number of pools in stack_pools. */ @@ -101,6 +101,34 @@ static int __init disable_stack_depot(char *str) } early_param("stack_depot_disable", disable_stack_depot); +static int __init parse_max_pools(char *str) +{ + const long long limit = (1LL << (DEPOT_POOL_INDEX_BITS)) - 1; + unsigned int max_pools; + int rv; + + rv = kstrtouint(str, 0, &max_pools); + if (rv) + return rv; + + if (max_pools < 1024) { + pr_err("stack_depot_max_pools below 1024, using default of %u\n", + stack_max_pools); + goto out; + } + + if (max_pools > limit) { + pr_err("stack_depot_max_pools exceeds %lld, using default of %u\n", + limit, stack_max_pools); + goto out; + } + + stack_max_pools = max_pools; +out: + return 0; +} +early_param("stack_depot_max_pools", parse_max_pools); + void __init stack_depot_request_early_init(void) { /* Too late to request early init now. */ @@ -182,6 +210,17 @@ int __init stack_depot_early_init(void) } init_stack_table(entries); + pr_info("allocating space for %u stack pools via memblock\n", + stack_max_pools); + stack_pools = + memblock_alloc(stack_max_pools * sizeof(void *), PAGE_SIZE); + if (!stack_pools) { + pr_err("stack pools allocation failed, disabling\n"); + memblock_free(stack_table, entries * sizeof(struct list_head)); + stack_depot_disabled = true; + return -ENOMEM; + } + return 0; } @@ -231,6 +270,16 @@ int stack_depot_init(void) stack_hash_mask = entries - 1; init_stack_table(entries); + pr_info("allocating space for %u stack pools via kvcalloc\n", + stack_max_pools); + stack_pools = kvcalloc(stack_max_pools, sizeof(void *), GFP_KERNEL); + if (!stack_pools) { + pr_err("stack pools allocation failed, disabling\n"); + kvfree(stack_table); + stack_depot_disabled = true; + ret = -ENOMEM; + } + out_unlock: mutex_unlock(&stack_depot_init_mutex); @@ -245,9 +294,9 @@ static bool depot_init_pool(void **prealloc) { lockdep_assert_held(&pool_lock); - if (unlikely(pools_num >= DEPOT_MAX_POOLS)) { + if (unlikely(pools_num >= stack_max_pools)) { /* Bail out if we reached the pool limit. */ - WARN_ON_ONCE(pools_num > DEPOT_MAX_POOLS); /* should never happen */ + WARN_ON_ONCE(pools_num > stack_max_pools); /* should never happen */ WARN_ON_ONCE(!new_pool); /* to avoid unnecessary pre-allocation */ WARN_ONCE(1, "Stack depot reached limit capacity"); return false; @@ -273,7 +322,7 @@ static bool depot_init_pool(void **prealloc) * NULL; do not reset to NULL if we have reached the maximum number of * pools. */ - if (pools_num < DEPOT_MAX_POOLS) + if (pools_num < stack_max_pools) WRITE_ONCE(new_pool, NULL); else WRITE_ONCE(new_pool, STACK_DEPOT_POISON); |