From: Vijayanand Jitta vjitta@codeaurora.org
mainline inclusion from mainline-v5.12-rc1 commit e1fdc403349c64fa58f4c163f4bf9b860b4db808 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I9GSSR
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Add a kernel parameter stack_depot_disable to disable stack depot. So that stack hash table doesn't consume any memory when stack depot is disabled.
The use case is CONFIG_PAGE_OWNER without page_owner=on. Without this patch, stackdepot will consume the memory for the hashtable. By default, it's 8M which is never trivial.
With this option, in CONFIG_PAGE_OWNER configured system, page_owner=off, stack_depot_disable in kernel command line, we could save the wasted memory for the hashtable.
[akpm@linux-foundation.org: fix CONFIG_STACKDEPOT=n build]
Link: https://lkml.kernel.org/r/1611749198-24316-2-git-send-email-vjitta@codeauror... Signed-off-by: Vinayak Menon vinmenon@codeaurora.org Signed-off-by: Vijayanand Jitta vjitta@codeaurora.org Cc: Alexander Potapenko glider@google.com Cc: Minchan Kim minchan@kernel.org Cc: Yogesh Lal ylal@codeaurora.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org
Conflicts: Documentation/admin-guide/kernel-parameters.txt include/linux/stackdepot.h init/main.c lib/stackdepot.c [context conflicts] Signed-off-by: Jinjiang Tu tujinjiang@huawei.com --- .../admin-guide/kernel-parameters.txt | 6 ++++ include/linux/stackdepot.h | 8 +++++ init/main.c | 2 ++ lib/stackdepot.c | 32 ++++++++++++++++--- 4 files changed, 44 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 5ad5cd51d015..de3afdddcf6a 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5543,6 +5543,12 @@ growing up) the main stack are reserved for no other mapping. Default value is 256 pages.
+ stack_depot_disable= [KNL] + Setting this to true through kernel command line will + disable the stack depot thereby saving the static memory + consumed by the stack hash table. By default this is set + to false. + stacktrace [FTRACE] Enabled the stack tracer on boot up.
diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 1cbe5ad0577d..22919a94ca19 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -19,5 +19,13 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries, unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries);
+#ifdef CONFIG_STACKDEPOT +int stack_depot_init(void); +#else +static inline int stack_depot_init(void) +{ + return 0; +} +#endif /* CONFIG_STACKDEPOT */
#endif diff --git a/init/main.c b/init/main.c index f06fbe79a84a..68284805d173 100644 --- a/init/main.c +++ b/init/main.c @@ -98,6 +98,7 @@ #include <linux/jump_label.h> #include <linux/kcsan.h> #include <linux/init_syscalls.h> +#include <linux/stackdepot.h> #include <linux/randomize_kstack.h>
#include <asm/io.h> @@ -829,6 +830,7 @@ static void __init mm_init(void) init_debug_pagealloc(); kfence_alloc_pool(); report_meminit(); + stack_depot_init(); mem_init(); /* page_owner must be initialized after buddy is ready */ page_ext_init_flatmem_late(); diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 3cab9ba618df..33e22f20ffa4 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -30,6 +30,7 @@ #include <linux/stackdepot.h> #include <linux/string.h> #include <linux/types.h> +#include <linux/memblock.h>
#define DEPOT_STACK_BITS (sizeof(depot_stack_handle_t) * 8)
@@ -146,9 +147,32 @@ static struct stack_record *depot_alloc_stack(unsigned long *entries, int size, #define STACK_HASH_MASK (STACK_HASH_SIZE - 1) #define STACK_HASH_SEED 0x9747b28c
-static struct stack_record *stack_table[STACK_HASH_SIZE] = { - [0 ... STACK_HASH_SIZE - 1] = NULL -}; +static bool stack_depot_disable; +static struct stack_record **stack_table; + +static int __init is_stack_depot_disabled(char *str) +{ + kstrtobool(str, &stack_depot_disable); + if (stack_depot_disable) { + pr_info("Stack Depot is disabled\n"); + stack_table = NULL; + } + return 0; +} +early_param("stack_depot_disable", is_stack_depot_disabled); + +int __init stack_depot_init(void) +{ + if (!stack_depot_disable) { + size_t size = (STACK_HASH_SIZE * sizeof(struct stack_record *)); + int i; + + stack_table = memblock_alloc(size, size); + for (i = 0; i < STACK_HASH_SIZE; i++) + stack_table[i] = NULL; + } + return 0; +}
/* Calculate hash for a stack */ static inline u32 hash_stack(unsigned long *entries, unsigned int size) @@ -242,7 +266,7 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries, unsigned long flags; u32 hash;
- if (unlikely(nr_entries == 0)) + if (unlikely(nr_entries == 0) || stack_depot_disable) goto fast_exit;
hash = hash_stack(entries, nr_entries);