From patchwork Fri Feb 10 21:16:06 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: andrey.konovalov@linux.dev X-Patchwork-Id: 13136467 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C119DC636D4 for ; Fri, 10 Feb 2023 21:19:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5C18F6B01A3; Fri, 10 Feb 2023 16:19:25 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 54A3B6B01A4; Fri, 10 Feb 2023 16:19:25 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 39CA66B01A5; Fri, 10 Feb 2023 16:19:25 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 22FD66B01A3 for ; Fri, 10 Feb 2023 16:19:25 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id DC39AAB7DE for ; Fri, 10 Feb 2023 21:19:24 +0000 (UTC) X-FDA: 80452648248.05.828DF06 Received: from out-248.mta1.migadu.com (out-248.mta1.migadu.com [95.215.58.248]) by imf03.hostedemail.com (Postfix) with ESMTP id E04A82001C for ; Fri, 10 Feb 2023 21:19:22 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=s10+K4Rz; spf=pass (imf03.hostedemail.com: domain of andrey.konovalov@linux.dev designates 95.215.58.248 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1676063963; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=FT29KRMbRE0UIrHSR8VL9ToKxsY1mNQpa5JLen40C60=; b=RazQX8TA9MwwHjJSN3odNzUFQOhVyjgl6IVF1WyyQ2L7zPJS5lEWtg+j6IvVa+T3va/x6l uNP7TBTcuVtuQyC3sKh7O4D2uD7a3HMb2C414J9IkFnJU9usaFfs1bU2tzk/iqPJxmp94i qFWSnxCRfpeiJsiFCt2WQOL5OrE/+xQ= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=s10+K4Rz; spf=pass (imf03.hostedemail.com: domain of andrey.konovalov@linux.dev designates 95.215.58.248 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1676063963; a=rsa-sha256; cv=none; b=ksGe3MrifN6UWQbDGrE1erJ2oTbim5ZaIdpwC4a8aPlkg31bys/RIR122KjLffWukm3oJj Gskz9Wfrb3Viqxd0y0Mgl0+xdTA877L3R55P1R85nBnEMsLMUwOziq8fGqfO4UzwbttG8V IB0Ph7Hgossln+650fDS3/ct2sGeZys= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1676063961; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FT29KRMbRE0UIrHSR8VL9ToKxsY1mNQpa5JLen40C60=; b=s10+K4Rzc2sALXbIT+1TmOUw/81gMdFkCt3qDr6ED6IWbAlMmTt/KRQMXBw6qBCR6MobWg d3HivIkbrsLLO9p7S+4pHdXxB1gdQs2OLVS4TRFlC/4OfM+P1PI3uxfXCz9h5ocVbc3BCx Y061miA3dkscw+XnPpB5bNkpLLfQj4s= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko Cc: Andrey Konovalov , Vlastimil Babka , kasan-dev@googlegroups.com, Evgenii Stepanov , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH v2 18/18] lib/stackdepot: move documentation comments to stackdepot.h Date: Fri, 10 Feb 2023 22:16:06 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: E04A82001C X-Stat-Signature: yxhgj3m68peed1fho6qg67njomr7c3q6 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1676063962-830932 X-HE-Meta: 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 hXEJ97aF WhWFmhVFbw4PpKFoRIS+aGn2Nv/LNKRhtDjokE7XCX/VZYQe7SQfOU5ELcjls2GTcG7S7x7hpW+S09AmCdJzRz1PvFn+nv8ONjFKh X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Andrey Konovalov Move all interface- and usage-related documentation comments to include/linux/stackdepot.h. It makes sense to have them in the header where they are available to the interface users. Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko --- include/linux/stackdepot.h | 87 ++++++++++++++++++++++++++++++++++++++ lib/stackdepot.c | 87 -------------------------------------- 2 files changed, 87 insertions(+), 87 deletions(-) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index afdf8ee7b597..91f038829eaa 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -2,6 +2,17 @@ /* * Stack depot - a stack trace storage that avoids duplication. * + * Stack depot is intended to be used by subsystems that need to store and + * later retrieve many potentially duplicated stack traces without wasting + * memory. + * + * For example, KASAN needs to save allocation and free stack traces for each + * object. Storing two stack traces per object requires a lot of memory (e.g. + * SLUB_DEBUG needs 256 bytes per object for that). Since allocation and free + * stack traces often repeat, using stack depot allows to save about 100x space. + * + * Stack traces are never removed from stack depot. + * * Author: Alexander Potapenko * Copyright (C) 2016 Google, Inc. * @@ -57,24 +68,100 @@ static inline void stack_depot_request_early_init(void) { } static inline int stack_depot_early_init(void) { return 0; } #endif +/** + * __stack_depot_save - Save a stack trace to stack depot + * + * @entries: Pointer to the stack trace + * @nr_entries: Number of frames in the stack + * @alloc_flags: Allocation GFP flags + * @can_alloc: Allocate stack pools (increased chance of failure if false) + * + * Saves a stack trace from @entries array of size @nr_entries. If @can_alloc is + * %true, stack depot can replenish the stack pools in case no space is left + * (allocates using GFP flags of @alloc_flags). If @can_alloc is %false, avoids + * any allocations and fails if no space is left to store the stack trace. + * + * If the provided stack trace comes from the interrupt context, only the part + * up to the interrupt entry is saved. + * + * Context: Any context, but setting @can_alloc to %false is required if + * alloc_pages() cannot be used from the current context. Currently + * this is the case for contexts where neither %GFP_ATOMIC nor + * %GFP_NOWAIT can be used (NMI, raw_spin_lock). + * + * Return: Handle of the stack struct stored in depot, 0 on failure + */ depot_stack_handle_t __stack_depot_save(unsigned long *entries, unsigned int nr_entries, gfp_t gfp_flags, bool can_alloc); +/** + * stack_depot_save - Save a stack trace to stack depot + * + * @entries: Pointer to the stack trace + * @nr_entries: Number of frames in the stack + * @alloc_flags: Allocation GFP flags + * + * Context: Contexts where allocations via alloc_pages() are allowed. + * See __stack_depot_save() for more details. + * + * Return: Handle of the stack trace stored in depot, 0 on failure + */ depot_stack_handle_t stack_depot_save(unsigned long *entries, unsigned int nr_entries, gfp_t gfp_flags); +/** + * stack_depot_fetch - Fetch a stack trace from stack depot + * + * @handle: Stack depot handle returned from stack_depot_save() + * @entries: Pointer to store the address of the stack trace + * + * Return: Number of frames for the fetched stack + */ unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries); +/** + * stack_depot_print - Print a stack trace from stack depot + * + * @stack: Stack depot handle returned from stack_depot_save() + */ void stack_depot_print(depot_stack_handle_t stack); +/** + * stack_depot_snprint - Print a stack trace from stack depot into a buffer + * + * @handle: Stack depot handle returned from stack_depot_save() + * @buf: Pointer to the print buffer + * @size: Size of the print buffer + * @spaces: Number of leading spaces to print + * + * Return: Number of bytes printed + */ int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, int spaces); +/** + * stack_depot_set_extra_bits - Set extra bits in a stack depot handle + * + * @handle: Stack depot handle returned from stack_depot_save() + * @extra_bits: Value to set the extra bits + * + * Return: Stack depot handle with extra bits set + * + * Stack depot handles have a few unused bits, which can be used for storing + * user-specific information. These bits are transparent to the stack depot. + */ depot_stack_handle_t __must_check stack_depot_set_extra_bits( depot_stack_handle_t handle, unsigned int extra_bits); +/** + * stack_depot_get_extra_bits - Retrieve extra bits from a stack depot handle + * + * @handle: Stack depot handle with extra bits saved + * + * Return: Extra bits retrieved from the stack depot handle + */ unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle); #endif diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 02bb6cdb69dc..ec772e78af39 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -2,21 +2,10 @@ /* * Stack depot - a stack trace storage that avoids duplication. * - * Stack depot is intended to be used by subsystems that need to store and - * later retrieve many potentially duplicated stack traces without wasting - * memory. - * - * For example, KASAN needs to save allocation and free stack traces for each - * object. Storing two stack traces per object requires a lot of memory (e.g. - * SLUB_DEBUG needs 256 bytes per object for that). Since allocation and free - * stack traces often repeat, using stack depot allows to save about 100x space. - * * Internally, stack depot maintains a hash table of unique stacktraces. The * stack traces themselves are stored contiguously one after another in a set * of separate page allocations. * - * Stack traces are never removed from stack depot. - * * Author: Alexander Potapenko * Copyright (C) 2016 Google, Inc. * @@ -360,29 +349,6 @@ static inline struct stack_record *find_stack(struct stack_record *bucket, return NULL; } -/** - * __stack_depot_save - Save a stack trace to stack depot - * - * @entries: Pointer to the stack trace - * @nr_entries: Number of frames in the stack - * @alloc_flags: Allocation GFP flags - * @can_alloc: Allocate stack pools (increased chance of failure if false) - * - * Saves a stack trace from @entries array of size @nr_entries. If @can_alloc is - * %true, stack depot can replenish the stack pools in case no space is left - * (allocates using GFP flags of @alloc_flags). If @can_alloc is %false, avoids - * any allocations and fails if no space is left to store the stack trace. - * - * If the provided stack trace comes from the interrupt context, only the part - * up to the interrupt entry is saved. - * - * Context: Any context, but setting @can_alloc to %false is required if - * alloc_pages() cannot be used from the current context. Currently - * this is the case for contexts where neither %GFP_ATOMIC nor - * %GFP_NOWAIT can be used (NMI, raw_spin_lock). - * - * Return: Handle of the stack struct stored in depot, 0 on failure - */ depot_stack_handle_t __stack_depot_save(unsigned long *entries, unsigned int nr_entries, gfp_t alloc_flags, bool can_alloc) @@ -477,18 +443,6 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, } EXPORT_SYMBOL_GPL(__stack_depot_save); -/** - * stack_depot_save - Save a stack trace to stack depot - * - * @entries: Pointer to the stack trace - * @nr_entries: Number of frames in the stack - * @alloc_flags: Allocation GFP flags - * - * Context: Contexts where allocations via alloc_pages() are allowed. - * See __stack_depot_save() for more details. - * - * Return: Handle of the stack trace stored in depot, 0 on failure - */ depot_stack_handle_t stack_depot_save(unsigned long *entries, unsigned int nr_entries, gfp_t alloc_flags) @@ -497,14 +451,6 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries, } EXPORT_SYMBOL_GPL(stack_depot_save); -/** - * stack_depot_fetch - Fetch a stack trace from stack depot - * - * @handle: Stack depot handle returned from stack_depot_save() - * @entries: Pointer to store the address of the stack trace - * - * Return: Number of frames for the fetched stack - */ unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries) { @@ -537,11 +483,6 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle, } EXPORT_SYMBOL_GPL(stack_depot_fetch); -/** - * stack_depot_print - Print a stack trace from stack depot - * - * @stack: Stack depot handle returned from stack_depot_save() - */ void stack_depot_print(depot_stack_handle_t stack) { unsigned long *entries; @@ -553,16 +494,6 @@ void stack_depot_print(depot_stack_handle_t stack) } EXPORT_SYMBOL_GPL(stack_depot_print); -/** - * stack_depot_snprint - Print a stack trace from stack depot into a buffer - * - * @handle: Stack depot handle returned from stack_depot_save() - * @buf: Pointer to the print buffer - * @size: Size of the print buffer - * @spaces: Number of leading spaces to print - * - * Return: Number of bytes printed - */ int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, int spaces) { @@ -575,17 +506,6 @@ int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, } EXPORT_SYMBOL_GPL(stack_depot_snprint); -/** - * stack_depot_set_extra_bits - Set extra bits in a stack depot handle - * - * @handle: Stack depot handle returned from stack_depot_save() - * @extra_bits: Value to set the extra bits - * - * Return: Stack depot handle with extra bits set - * - * Stack depot handles have a few unused bits, which can be used for storing - * user-specific information. These bits are transparent to the stack depot. - */ depot_stack_handle_t __must_check stack_depot_set_extra_bits( depot_stack_handle_t handle, unsigned int extra_bits) { @@ -600,13 +520,6 @@ depot_stack_handle_t __must_check stack_depot_set_extra_bits( } EXPORT_SYMBOL(stack_depot_set_extra_bits); -/** - * stack_depot_get_extra_bits - Retrieve extra bits from a stack depot handle - * - * @handle: Stack depot handle with extra bits saved - * - * Return: Extra bits retrieved from the stack depot handle - */ unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle) { union handle_parts parts = { .handle = handle };