From patchwork Mon Nov 20 17:47:06 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: 13461822 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 CF3D2C5AD4C for ; Mon, 20 Nov 2023 17:48:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 97F5B6B034E; Mon, 20 Nov 2023 12:48:37 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 907326B0351; Mon, 20 Nov 2023 12:48:37 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6ED6D6B034F; Mon, 20 Nov 2023 12:48:37 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 404BE6B0351 for ; Mon, 20 Nov 2023 12:48:37 -0500 (EST) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 1E7E4140319 for ; Mon, 20 Nov 2023 17:48:37 +0000 (UTC) X-FDA: 81479067474.18.3E91E0C Received: from out-185.mta0.migadu.com (out-185.mta0.migadu.com [91.218.175.185]) by imf14.hostedemail.com (Postfix) with ESMTP id 5DCD5100009 for ; Mon, 20 Nov 2023 17:48:35 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=Kt5p6zSc; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf14.hostedemail.com: domain of andrey.konovalov@linux.dev designates 91.218.175.185 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1700502515; 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=9IYHxZGEq/qB2Qlddv235LQK4ccHh5XyxORYKM2z5Wc=; b=FAaoSEIZVbq/hl6ieJZeAtDgCJnnf9aIsFJU9yKFLW2RpkAfwL5EvBDadv4/izipNv6dVk +3GcqY4mugor+FG03vLty8VNmkpQgg21YpekZCsyi9/Bg/bXKZCoI1IS1ZXIbwq7CapmDm Rm4At615DX9cJPeEkKG/s6B+W1HI+4c= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=Kt5p6zSc; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf14.hostedemail.com: domain of andrey.konovalov@linux.dev designates 91.218.175.185 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1700502515; a=rsa-sha256; cv=none; b=FN/QoGU4V3jZeKHPbrWW/YmoIkfVSi4wVQbUIkVjMFn/CxCHdjz8pqchMYejbN2kwTb/KQ gmt19W3PhQ7vWwArDNk6QdloG/clP3dlq2YJU6vFpd+4wMSKxLMzbkDLjKl7sz/KDY35i7 vgyi9XONE2yOq34/Abc7u4RMYyumRv4= 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=1700502513; 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=9IYHxZGEq/qB2Qlddv235LQK4ccHh5XyxORYKM2z5Wc=; b=Kt5p6zScvUKaXsHar2QlUefWEFtJ6Uws7kbkfGgrB5cxpVMGSn2WXhKYFJ5MhB50RhntDQ K7N0E2IbssHoPp6AeWgnF1sPLT3aDEF/nGgRuJ546AoCXVl6clQWGAmNHZLEBxlZNtF5g9 xiIqlvFkZnYs+J6Hza0Jtp/FsRG4z5s= From: andrey.konovalov@linux.dev To: Andrew Morton Cc: Andrey Konovalov , Marco Elver , Alexander Potapenko , Dmitry Vyukov , Vlastimil Babka , kasan-dev@googlegroups.com, Evgenii Stepanov , Oscar Salvador , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH v4 08/22] lib/stackdepot: rework helpers for depot_alloc_stack Date: Mon, 20 Nov 2023 18:47:06 +0100 Message-Id: <71fb144d42b701fcb46708d7f4be6801a4a8270e.1700502145.git.andreyknvl@google.com> In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Stat-Signature: o3ne7cbxqnyrbba1a4jiz1u3ggbcz8rw X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 5DCD5100009 X-HE-Tag: 1700502515-442004 X-HE-Meta: U2FsdGVkX18X6H8I1+eDmZzc5h9MeV040gjvCgd9kLlFSKjIfGlaju/Xh4RZtrRKC5S7NjdtjU4Pt6GsJ8+I1dD7jmgttoSABUkmH2ELxQR7ih+Ttjs9f9NBoDTbdyliKbJMBiU5QcXRjNpAcL40aoxcMZqS/qpqhbgNY2q4fq9gMDY/tKNcNm9EgnNOcm8cQofBGpLr4P8oeEL3qrNyiNnCtOu1ON7YGAnoSND76TNuZELlcazYCxaRPeww20VLFu+CnqHTVkMxwFVmzP1vGhgq9CfGbm05FLKa/VPStCdivIOp/Og4wyg/NoI6SIGJNTeijI1Kg4tysyT+ybg/1ATTc7rU5lsJOZ1JcnqJ5Z+3bUz6GZXMwwmHtRhdHpRgsCFHMZ3l1VO63BXxarpRbcvX4+dMHYY+xPDRlEbJeAhfm2J44mYWKZf6HVQP6gKKhq87nH98bPCpblDsponHJ4lQErtdmUBurK6fAl57E14u0+sR7Q9r/Keu7pFdSu/ofmYlBh+V0bMbdafvVmaWgVAl3fAU0BCO8U+QprmoCegEyD2euhaYvF4FUetLzRXsR/AqKikL/V78Ls/6+wq3W7HW491KHaV/+CDaD6r+a7aGNASCbBWCHhyWwKOE79eqCV6SxdonraRYQYSeTt26CJc1CP8jiubb+vJiMhCbJfPI44ZkxvWbYjU9t5DtYaBd1cegyprqVKnVaSECgCG+auWVzhlVPw0t4q2ndIAEHCXQfYcVBgjnYGYMr1PijzUf4WEJ20stZNr+y7YFQaMUaqkmIN5yjYlbfzGO8+q+WtZthEq8x79NOEPyisirWk+TBVV7Of6MqUtQcNyMJXk6pHlqkVUlffe4yIKK0eif6qPqvreM9tCEz+SxtbhrDS/gOFIKocAOA64XU6XJ/Ysdcu+OUZ/jpRBhY8a4WNVSPlUeEl7QEsDk13OagrWjTbEzffDURDz5VwdFseCjQzj A3J3tPTZ EpsObRF5rtpUMA85swVkyipe1PNPf/sR912cEkXLT4snjn6SJolLqAc+NExG4wuFR8jrYqUB0o+kBwX/r8sdgZQwREb1Hcn2XvOzYeQ/vbPG6RTUWOT1DsTup3Q== 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: List-Subscribe: List-Unsubscribe: From: Andrey Konovalov Split code in depot_alloc_stack and depot_init_pool into 3 functions: 1. depot_keep_next_pool that keeps preallocated memory for the next pool if required. 2. depot_update_pools that moves on to the next pool if there's no space left in the current pool, uses preallocated memory for the new current pool if required, and calls depot_keep_next_pool otherwise. 3. depot_alloc_stack that calls depot_update_pools and then allocates a stack record as before. This makes it somewhat easier to follow the logic of depot_alloc_stack and also serves as a preparation for implementing the eviction of stack records from the stack depot. Reviewed-by: Alexander Potapenko Signed-off-by: Andrey Konovalov Reviewed-by: Oscar Salvador --- Changes v2->v3: - Add parentheses when referring to function calls in comments. --- lib/stackdepot.c | 86 +++++++++++++++++++++++++++--------------------- 1 file changed, 49 insertions(+), 37 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index cfa3c6c7cc2e..b3af868627f4 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -225,11 +225,11 @@ int stack_depot_init(void) } EXPORT_SYMBOL_GPL(stack_depot_init); -/* Uses preallocated memory to initialize a new stack depot pool. */ -static void depot_init_pool(void **prealloc) +/* Keeps the preallocated memory to be used for the next stack depot pool. */ +static void depot_keep_next_pool(void **prealloc) { /* - * If the next pool is already initialized or the maximum number of + * If the next pool is already saved or the maximum number of * pools is reached, do not use the preallocated memory. * Access next_pool_required non-atomically, as there are no concurrent * write accesses to this variable. @@ -237,44 +237,34 @@ static void depot_init_pool(void **prealloc) if (!next_pool_required) return; - /* Check if the current pool is not yet allocated. */ - if (stack_pools[pool_index] == NULL) { - /* Use the preallocated memory for the current pool. */ - stack_pools[pool_index] = *prealloc; + /* + * Use the preallocated memory for the next pool + * as long as we do not exceed the maximum number of pools. + */ + if (pool_index + 1 < DEPOT_MAX_POOLS) { + stack_pools[pool_index + 1] = *prealloc; *prealloc = NULL; - } else { - /* - * Otherwise, use the preallocated memory for the next pool - * as long as we do not exceed the maximum number of pools. - */ - if (pool_index + 1 < DEPOT_MAX_POOLS) { - stack_pools[pool_index + 1] = *prealloc; - *prealloc = NULL; - } - /* - * At this point, either the next pool is initialized or the - * maximum number of pools is reached. In either case, take - * note that initializing another pool is not required. - * smp_store_release() pairs with smp_load_acquire() in - * stack_depot_save(). - */ - smp_store_release(&next_pool_required, 0); } + + /* + * At this point, either the next pool is kept or the maximum + * number of pools is reached. In either case, take note that + * keeping another pool is not required. + * smp_store_release() pairs with smp_load_acquire() in + * stack_depot_save(). + */ + smp_store_release(&next_pool_required, 0); } -/* Allocates a new stack in a stack depot pool. */ -static struct stack_record * -depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) +/* Updates references to the current and the next stack depot pools. */ +static bool depot_update_pools(size_t required_size, void **prealloc) { - struct stack_record *stack; - size_t required_size = DEPOT_STACK_RECORD_SIZE; - /* Check if there is not enough space in the current pool. */ if (unlikely(pool_offset + required_size > DEPOT_POOL_SIZE)) { /* Bail out if we reached the pool limit. */ if (unlikely(pool_index + 1 >= DEPOT_MAX_POOLS)) { WARN_ONCE(1, "Stack depot reached limit capacity"); - return NULL; + return false; } /* @@ -284,9 +274,10 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) */ WRITE_ONCE(pool_index, pool_index + 1); pool_offset = 0; + /* * If the maximum number of pools is not reached, take note - * that the next pool needs to initialized. + * that the next pool needs to be initialized. * smp_store_release() pairs with smp_load_acquire() in * stack_depot_save(). */ @@ -294,9 +285,30 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) smp_store_release(&next_pool_required, 1); } - /* Assign the preallocated memory to a pool if required. */ + /* Check if the current pool is not yet allocated. */ + if (*prealloc && stack_pools[pool_index] == NULL) { + /* Use the preallocated memory for the current pool. */ + stack_pools[pool_index] = *prealloc; + *prealloc = NULL; + return true; + } + + /* Otherwise, try using the preallocated memory for the next pool. */ if (*prealloc) - depot_init_pool(prealloc); + depot_keep_next_pool(prealloc); + return true; +} + +/* Allocates a new stack in a stack depot pool. */ +static struct stack_record * +depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) +{ + struct stack_record *stack; + size_t required_size = DEPOT_STACK_RECORD_SIZE; + + /* Update current and next pools if required and possible. */ + if (!depot_update_pools(required_size, prealloc)) + return NULL; /* Check if we have a pool to save the stack trace. */ if (stack_pools[pool_index] == NULL) @@ -330,7 +342,7 @@ static struct stack_record *depot_fetch_stack(depot_stack_handle_t handle) union handle_parts parts = { .handle = handle }; /* * READ_ONCE() pairs with potential concurrent write in - * depot_alloc_stack(). + * depot_update_pools(). */ int pool_index_cached = READ_ONCE(pool_index); void *pool; @@ -430,7 +442,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, * the memory now - we won't be able to do that under the lock. * * smp_load_acquire() pairs with smp_store_release() in - * depot_alloc_stack() and depot_init_pool(). + * depot_update_pools() and depot_keep_next_pool(). */ if (unlikely(can_alloc && smp_load_acquire(&next_pool_required))) { /* @@ -467,7 +479,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, * Stack depot already contains this stack trace, but let's * keep the preallocated memory for the future. */ - depot_init_pool(&prealloc); + depot_keep_next_pool(&prealloc); } raw_spin_unlock_irqrestore(&pool_lock, flags);