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Tue, 30 Aug 2022 14:50:14 -0700 (PDT) Date: Tue, 30 Aug 2022 14:49:08 -0700 In-Reply-To: <20220830214919.53220-1-surenb@google.com> Mime-Version: 1.0 References: <20220830214919.53220-1-surenb@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220830214919.53220-20-surenb@google.com> Subject: [RFC PATCH 19/30] move stack capture functionality into a separate function for reuse From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: kent.overstreet@linux.dev, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, roman.gushchin@linux.dev, mgorman@suse.de, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, void@manifault.com, peterz@infradead.org, juri.lelli@redhat.com, ldufour@linux.ibm.com, peterx@redhat.com, david@redhat.com, axboe@kernel.dk, mcgrof@kernel.org, masahiroy@kernel.org, nathan@kernel.org, changbin.du@intel.com, ytcoode@gmail.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com, vschneid@redhat.com, cl@linux.com, penberg@kernel.org, iamjoonsoo.kim@lge.com, 42.hyeyoo@gmail.com, glider@google.com, elver@google.com, dvyukov@google.com, shakeelb@google.com, songmuchun@bytedance.com, arnd@arndb.de, jbaron@akamai.com, rientjes@google.com, minchan@google.com, kaleshsingh@google.com, surenb@google.com, kernel-team@android.com, linux-mm@kvack.org, iommu@lists.linux.dev, kasan-dev@googlegroups.com, io-uring@vger.kernel.org, linux-arch@vger.kernel.org, xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org, linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org Make save_stack() function part of stackdepot API to be used outside of page_owner. Also rename task_struct's in_page_owner to in_capture_stack flag to better convey the wider use of this flag. Signed-off-by: Suren Baghdasaryan --- include/linux/sched.h | 6 ++-- include/linux/stackdepot.h | 3 ++ lib/stackdepot.c | 68 ++++++++++++++++++++++++++++++++++++++ mm/page_owner.c | 52 ++--------------------------- 4 files changed, 77 insertions(+), 52 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index e7b2f8a5c711..d06cad6c14bd 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -930,9 +930,9 @@ struct task_struct { /* Stalled due to lack of memory */ unsigned in_memstall:1; #endif -#ifdef CONFIG_PAGE_OWNER - /* Used by page_owner=on to detect recursion in page tracking. */ - unsigned in_page_owner:1; +#ifdef CONFIG_STACKDEPOT + /* Used by stack_depot_capture_stack to detect recursion. */ + unsigned in_capture_stack:1; #endif #ifdef CONFIG_EVENTFD /* Recursion prevention for eventfd_signal() */ diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index bc2797955de9..8dc9fdb2c4dd 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -64,4 +64,7 @@ int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, void stack_depot_print(depot_stack_handle_t stack); +bool stack_depot_capture_init(void); +depot_stack_handle_t stack_depot_capture_stack(gfp_t flags); + #endif diff --git a/lib/stackdepot.c b/lib/stackdepot.c index e73fda23388d..c8615bd6dc25 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -514,3 +514,71 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries, return __stack_depot_save(entries, nr_entries, alloc_flags, true); } EXPORT_SYMBOL_GPL(stack_depot_save); + +static depot_stack_handle_t recursion_handle; +static depot_stack_handle_t failure_handle; + +static __always_inline depot_stack_handle_t create_custom_stack(void) +{ + unsigned long entries[4]; + unsigned int nr_entries; + + nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0); + return stack_depot_save(entries, nr_entries, GFP_KERNEL); +} + +static noinline void register_recursion_stack(void) +{ + recursion_handle = create_custom_stack(); +} + +static noinline void register_failure_stack(void) +{ + failure_handle = create_custom_stack(); +} + +bool stack_depot_capture_init(void) +{ + static DEFINE_MUTEX(stack_depot_capture_init_mutex); + static bool utility_stacks_ready; + + mutex_lock(&stack_depot_capture_init_mutex); + if (!utility_stacks_ready) { + register_recursion_stack(); + register_failure_stack(); + utility_stacks_ready = true; + } + mutex_unlock(&stack_depot_capture_init_mutex); + + return utility_stacks_ready; +} + +/* TODO: teach stack_depot_capture_stack to use off stack temporal storage */ +#define CAPTURE_STACK_DEPTH (16) + +depot_stack_handle_t stack_depot_capture_stack(gfp_t flags) +{ + unsigned long entries[CAPTURE_STACK_DEPTH]; + depot_stack_handle_t handle; + unsigned int nr_entries; + + /* + * Avoid recursion. + * + * Sometimes page metadata allocation tracking requires more + * memory to be allocated: + * - when new stack trace is saved to stack depot + * - when backtrace itself is calculated (ia64) + */ + if (current->in_capture_stack) + return recursion_handle; + current->in_capture_stack = 1; + + nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2); + handle = stack_depot_save(entries, nr_entries, flags); + if (!handle) + handle = failure_handle; + + current->in_capture_stack = 0; + return handle; +} diff --git a/mm/page_owner.c b/mm/page_owner.c index fd4af1ad34b8..c3173e34a779 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -15,12 +15,6 @@ #include "internal.h" -/* - * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack) - * to use off stack temporal storage - */ -#define PAGE_OWNER_STACK_DEPTH (16) - struct page_owner { unsigned short order; short last_migrate_reason; @@ -37,8 +31,6 @@ struct page_owner { static bool page_owner_enabled __initdata; DEFINE_STATIC_KEY_FALSE(page_owner_inited); -static depot_stack_handle_t dummy_handle; -static depot_stack_handle_t failure_handle; static depot_stack_handle_t early_handle; static void init_early_allocated_pages(void); @@ -68,16 +60,6 @@ static __always_inline depot_stack_handle_t create_dummy_stack(void) return stack_depot_save(entries, nr_entries, GFP_KERNEL); } -static noinline void register_dummy_stack(void) -{ - dummy_handle = create_dummy_stack(); -} - -static noinline void register_failure_stack(void) -{ - failure_handle = create_dummy_stack(); -} - static noinline void register_early_stack(void) { early_handle = create_dummy_stack(); @@ -88,8 +70,7 @@ static __init void init_page_owner(void) if (!page_owner_enabled) return; - register_dummy_stack(); - register_failure_stack(); + stack_depot_capture_init(); register_early_stack(); static_branch_enable(&page_owner_inited); init_early_allocated_pages(); @@ -106,33 +87,6 @@ static inline struct page_owner *get_page_owner(struct page_ext *page_ext) return (void *)page_ext + page_owner_ops.offset; } -static noinline depot_stack_handle_t save_stack(gfp_t flags) -{ - unsigned long entries[PAGE_OWNER_STACK_DEPTH]; - depot_stack_handle_t handle; - unsigned int nr_entries; - - /* - * Avoid recursion. - * - * Sometimes page metadata allocation tracking requires more - * memory to be allocated: - * - when new stack trace is saved to stack depot - * - when backtrace itself is calculated (ia64) - */ - if (current->in_page_owner) - return dummy_handle; - current->in_page_owner = 1; - - nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2); - handle = stack_depot_save(entries, nr_entries, flags); - if (!handle) - handle = failure_handle; - - current->in_page_owner = 0; - return handle; -} - void __reset_page_owner(struct page *page, unsigned short order) { int i; @@ -145,7 +99,7 @@ void __reset_page_owner(struct page *page, unsigned short order) if (unlikely(!page_ext)) return; - handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); + handle = stack_depot_capture_stack(GFP_NOWAIT | __GFP_NOWARN); for (i = 0; i < (1 << order); i++) { __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); page_owner = get_page_owner(page_ext); @@ -189,7 +143,7 @@ noinline void __set_page_owner(struct page *page, unsigned short order, if (unlikely(!page_ext)) return; - handle = save_stack(gfp_mask); + handle = stack_depot_capture_stack(gfp_mask); __set_page_owner_handle(page_ext, handle, order, gfp_mask); }