From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44C92CA9EA9 for ; Fri, 18 Oct 2019 22:24:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 16C89222C3 for ; Fri, 18 Oct 2019 22:24:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571437490; bh=q4gA284Acw4GIJYTIVOl+MOguuyn/m44jy1aaSgaG34=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ccGjRt5o4nDgAFiFUBRx2iD2P2Zr4YKuKxcoBEG4ktqnJG0RORZVuTi3EhxvzbzQ4 hRocmvj2A53ajOY02wFEpq+r5wIHnNS3LMdd/zMbj0ptLXogq1+XBs9V/FNrTPav4A uO6vK7dtZFYEGWmPOC1BTTMxT4ZV5e5PyYMGsWYE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394613AbfJRWYt (ORCPT ); Fri, 18 Oct 2019 18:24:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:36600 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728877AbfJRWEw (ORCPT ); Fri, 18 Oct 2019 18:04:52 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C35A2222D1; Fri, 18 Oct 2019 22:04:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571436291; bh=q4gA284Acw4GIJYTIVOl+MOguuyn/m44jy1aaSgaG34=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0pKD7R3Cwd6l868zR6qayhWRK6BQzYB5bqBC/6HkQbkxboJ2jxSjWygwTzzjZgrQt hMFspj5J5U7kr6IF/5XyY30URCdDYl/it5hH8s3Yg0K950/3eEcs/tuR+7726XeFpo k6ujJJdmAaxZj+heZ7HZPCupJgGQ8GkewYNOZB4A= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Song Liu , Hechao Li , Peter Zijlstra , kernel-team@fb.com, Jie Meng , Linus Torvalds , Thomas Gleixner , Ingo Molnar , Sasha Levin Subject: [PATCH AUTOSEL 5.3 65/89] perf/core: Rework memory accounting in perf_mmap() Date: Fri, 18 Oct 2019 18:03:00 -0400 Message-Id: <20191018220324.8165-65-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191018220324.8165-1-sashal@kernel.org> References: <20191018220324.8165-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Song Liu [ Upstream commit d44248a41337731a111374822d7d4451b64e73e4 ] perf_mmap() always increases user->locked_vm. As a result, "extra" could grow bigger than "user_extra", which doesn't make sense. Here is an example case: (Note: Assume "user_lock_limit" is very small.) | # of perf_mmap calls |vma->vm_mm->pinned_vm|user->locked_vm| | 0 | 0 | 0 | | 1 | user_extra | user_extra | | 2 | 3 * user_extra | 2 * user_extra| | 3 | 6 * user_extra | 3 * user_extra| | 4 | 10 * user_extra | 4 * user_extra| Fix this by maintaining proper user_extra and extra. Reviewed-By: Hechao Li Reported-by: Hechao Li Signed-off-by: Song Liu Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Jie Meng Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20190904214618.3795672-1-songliubraving@fb.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- kernel/events/core.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 0463c1151baeb..a0120bdbce177 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5585,7 +5585,8 @@ static void perf_mmap_close(struct vm_area_struct *vma) * undo the VM accounting. */ - atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm); + atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked, + &mmap_user->locked_vm); atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm); free_uid(mmap_user); @@ -5729,8 +5730,20 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) user_locked = atomic_long_read(&user->locked_vm) + user_extra; - if (user_locked > user_lock_limit) + if (user_locked <= user_lock_limit) { + /* charge all to locked_vm */ + } else if (atomic_long_read(&user->locked_vm) >= user_lock_limit) { + /* charge all to pinned_vm */ + extra = user_extra; + user_extra = 0; + } else { + /* + * charge locked_vm until it hits user_lock_limit; + * charge the rest from pinned_vm + */ extra = user_locked - user_lock_limit; + user_extra -= extra; + } lock_limit = rlimit(RLIMIT_MEMLOCK); lock_limit >>= PAGE_SHIFT; -- 2.20.1