From patchwork Fri Feb 10 21:16:01 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: 13136462 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 72825C636D4 for ; Fri, 10 Feb 2023 21:18:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DB33B6B0198; Fri, 10 Feb 2023 16:18:21 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id CC4216B019A; Fri, 10 Feb 2023 16:18:21 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AEF7C6B019B; Fri, 10 Feb 2023 16:18:21 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 917756B0198 for ; Fri, 10 Feb 2023 16:18:21 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 68515C0327 for ; Fri, 10 Feb 2023 21:18:21 +0000 (UTC) X-FDA: 80452645602.19.19EC8C1 Received: from out-52.mta1.migadu.com (out-52.mta1.migadu.com [95.215.58.52]) by imf10.hostedemail.com (Postfix) with ESMTP id 862C6C0007 for ; Fri, 10 Feb 2023 21:18:19 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="sVBTl7/5"; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf10.hostedemail.com: domain of andrey.konovalov@linux.dev designates 95.215.58.52 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=1676063899; 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=pGvDrOxyRt5kOFDmqXD5ITBuCpaHJonxkPgV6Sd4X2o=; b=RHsgclwFPESLAWodD9vmQIj4nWizlQ8SPAu7mowkfCIjBxQQuz9y8zqQhQOODj2QyAs/EV UeAyXGOouX42XBrTOkivgK+5EdgAJxl4OOtrtOHjNY2XsYB9ciqecsQEp+bLH4cAo6OFJ1 QE1ROBake8hlt3796B1++E3Wozde0qA= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="sVBTl7/5"; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf10.hostedemail.com: domain of andrey.konovalov@linux.dev designates 95.215.58.52 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1676063899; a=rsa-sha256; cv=none; b=L9R2vMkbEBX2RNvXjH54+Gh6L/DTZFnz7BQ5NnLWxkJ2UKWbcR/REIo5DEdPVi8QVy33HB fYsVEqWZ51ZXnDpUDwvX0toh3aDm8n6lZJvmj0I6WQpbV4QRF1sUc2HUEmpgdsQNKgORlI dFPvuU9Bu+ap+o/9Fk1JK2Vb2xHLJAE= 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=1676063898; 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=pGvDrOxyRt5kOFDmqXD5ITBuCpaHJonxkPgV6Sd4X2o=; b=sVBTl7/5HAlYJsoNTAYJS7jHmyG0mwufQdpCh0QT0n6Tk9BlAh4+4jHAXFjNeAehSp09ID IEpp2QiI5YzquQvB0+kSXtzyz/47zqk8vIOAWAnjB9JeZRWKZTC7iXXkh/2GlVESua2t5Y R7dMt2pIa9/i109Fj4DEUmTYzXbV/98= 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 13/18] lib/stackdepot: annotate depot_init_pool and depot_alloc_stack Date: Fri, 10 Feb 2023 22:16:01 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 862C6C0007 X-Stat-Signature: urbpscws5nh9u8nrnrc68rcykwhh46wn X-HE-Tag: 1676063899-158855 X-HE-Meta: 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 RU3aZHtq e/X1JFSuO0xblK+pf2zaI4z1YlACpJJ6JRcF4/TUYF0nDnV0Ieakc7v3sNV9AQ4C8pS4QCQm6K4mzcr8GUHiRVpsW1e3qsv0NA/5Afplljiw26W5BIJR+F9lVqr/bb8ghRawxuWQTZu1zxa2ZPoKYSXhfjw== 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 Clean up the exisiting comments and add new ones to depot_init_pool and depot_alloc_stack. As a part of the clean-up, remove mentions of which variable is accessed by smp_store_release and smp_load_acquire: it is clear as is from the code. Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko --- lib/stackdepot.c | 34 ++++++++++++++++++++++++---------- 1 file changed, 24 insertions(+), 10 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index d4d988276b91..c4bc198c3d93 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -218,32 +218,39 @@ 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) { /* - * This smp_load_acquire() pairs with smp_store_release() to - * |next_pool_inited| below and in depot_alloc_stack(). + * smp_load_acquire() here pairs with smp_store_release() below and + * in depot_alloc_stack(). */ if (smp_load_acquire(&next_pool_inited)) 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; *prealloc = NULL; } else { - /* If this is the last depot pool, do not touch the next one. */ + /* + * 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; } /* - * This smp_store_release pairs with smp_load_acquire() from - * |next_pool_inited| above and in stack_depot_save(). + * This smp_store_release pairs with smp_load_acquire() above + * and in stack_depot_save(). */ smp_store_release(&next_pool_inited, 1); } } -/* Allocation of a new stack in raw storage */ +/* 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) { @@ -252,28 +259,35 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) required_size = ALIGN(required_size, 1 << DEPOT_STACK_ALIGN); + /* 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; } + + /* Move on to the next pool. */ pool_index++; pool_offset = 0; /* - * smp_store_release() here pairs with smp_load_acquire() from - * |next_pool_inited| in stack_depot_save() and - * depot_init_pool(). + * smp_store_release() here pairs with smp_load_acquire() in + * stack_depot_save() and depot_init_pool(). */ if (pool_index + 1 < DEPOT_MAX_POOLS) smp_store_release(&next_pool_inited, 0); } + + /* Assign the preallocated memory to a pool if required. */ if (*prealloc) depot_init_pool(prealloc); + + /* Check if we have a pool to save the stack trace. */ if (stack_pools[pool_index] == NULL) return NULL; + /* Save the stack trace. */ stack = stack_pools[pool_index] + pool_offset; - stack->hash = hash; stack->size = size; stack->handle.pool_index = pool_index;