From patchwork Tue Sep 26 03:10:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rik van Riel X-Patchwork-Id: 144697 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:cae8:0:b0:403:3b70:6f57 with SMTP id r8csp1639790vqu; Mon, 25 Sep 2023 20:14:11 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEidfz5e4NU7Hcg7K/IywrAJRq1QB0g3Iz1+KW2kwPxmmkxF8273spFHrxKuGA0dQnlgjKD X-Received: by 2002:a05:6a20:3948:b0:140:61f8:53f6 with SMTP id r8-20020a056a20394800b0014061f853f6mr2188695pzg.29.1695698050853; Mon, 25 Sep 2023 20:14:10 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1695698050; cv=none; d=google.com; s=arc-20160816; b=l8ReoqIEuz1Fwk6JcEYoyhgs4sIlYFl/sV9LLghFJX+YfnKLdtxWdm2DKEy4jrXlZU ndx4iElswQpJCqjzhaGqkDelJd/52+GESMG1XqQ10EGlMCjBxwVgD475Wt62L4GXRCKk wzNB0MwOM08eAB9XtuH9tBG198As7tb6ShXdZ3WtERlbI3SfYPy1tZ5UJQJiCKvdOL8w IZ7FAecYd/XxmTDjCoFCcc0pvu2dxVg4YJQl6dT0u1RkIng0gQNRtOn5I1X74UVWyDrS wQh9w/2g0+N6v/YAnNENSnkcQpTYsqQ/yRTEu8lYvkl8ErhATCeWqkVPXrjMM9GnG0PZ zLxg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=Lj4Z6Ul00eCWNgyGLnZw82tbqm4QntGZxAS4UjBFJEM=; fh=volCnvwF0JDFbcV4TVnX2BKg6+uih1swgq+cGsuUYCI=; b=DrsNKT0oTMQ7+hn4VH4hX4Z3cpt+ocosc/OIla/RDOkB1CQQXe9LrVb86uEeu3/yhu 5bM6F3b4jYDrGHJ6AlLNd6iSgjsaQJEwCcRG4WTN8+je4EDZWPbPRaKwnrct/b5H9Npr qeJCYq2KKNLU1cGwCdRwICSTsT0r08JEbUXMWEtHuDxqYY+ENOIM0keCnsCEvp77IDFY fpf7FOWw+0CXOEPoeh+Y9JTVOFzcnXxiLC4uLN/HtwGGLmd9etodcSKurBm6TtfmvbBi v8Ap+Gz6ByAfcJ0HMlVhGNpRQtxHvq8SubHgWirCKU7MggN4S6OtLL5n+QPreU2jbrAH mHXg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from agentk.vger.email (agentk.vger.email. [23.128.96.32]) by mx.google.com with ESMTPS id p19-20020a639513000000b00573f786103dsi8826141pgd.754.2023.09.25.20.14.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Sep 2023 20:14:10 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) client-ip=23.128.96.32; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by agentk.vger.email (Postfix) with ESMTP id 2A926819AD9E; Mon, 25 Sep 2023 20:14:08 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at agentk.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232097AbjIZDNx (ORCPT + 27 others); Mon, 25 Sep 2023 23:13:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231226AbjIZDNq (ORCPT ); Mon, 25 Sep 2023 23:13:46 -0400 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 20733A3 for ; Mon, 25 Sep 2023 20:13:40 -0700 (PDT) Received: from imladris.home.surriel.com ([10.0.13.28] helo=imladris.surriel.com) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1qkyVD-00025y-0w; Mon, 25 Sep 2023 23:12:47 -0400 From: riel@surriel.com To: linux-kernel@vger.kernel.org Cc: kernel-team@meta.com, linux-mm@kvack.org, akpm@linux-foundation.org, muchun.song@linux.dev, mike.kravetz@oracle.com, leit@meta.com, willy@infradead.org, Rik van Riel Subject: [PATCH 1/3] hugetlbfs: extend hugetlb_vma_lock to private VMAs Date: Mon, 25 Sep 2023 23:10:50 -0400 Message-ID: <20230926031245.795759-2-riel@surriel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230926031245.795759-1-riel@surriel.com> References: <20230926031245.795759-1-riel@surriel.com> MIME-Version: 1.0 Sender: riel@surriel.com X-Spam-Status: No, score=-0.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on agentk.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (agentk.vger.email [0.0.0.0]); Mon, 25 Sep 2023 20:14:08 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1778068279504026297 X-GMAIL-MSGID: 1778068279504026297 From: Rik van Riel Extend the locking scheme used to protect shared hugetlb mappings from truncate vs page fault races, in order to protect private hugetlb mappings (with resv_map) against MADV_DONTNEED. Add a read-write semaphore to the resv_map data structure, and use that from the hugetlb_vma_(un)lock_* functions, in preparation for closing the race between MADV_DONTNEED and page faults. Signed-off-by: Rik van Riel Reviewed-by: Mike Kravetz --- include/linux/hugetlb.h | 6 ++++++ mm/hugetlb.c | 41 +++++++++++++++++++++++++++++++++++++---- 2 files changed, 43 insertions(+), 4 deletions(-) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 5b2626063f4f..694928fa06a3 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -60,6 +60,7 @@ struct resv_map { long adds_in_progress; struct list_head region_cache; long region_cache_count; + struct rw_semaphore rw_sema; #ifdef CONFIG_CGROUP_HUGETLB /* * On private mappings, the counter to uncharge reservations is stored @@ -1231,6 +1232,11 @@ static inline bool __vma_shareable_lock(struct vm_area_struct *vma) return (vma->vm_flags & VM_MAYSHARE) && vma->vm_private_data; } +static inline bool __vma_private_lock(struct vm_area_struct *vma) +{ + return (!(vma->vm_flags & VM_MAYSHARE)) && vma->vm_private_data; +} + /* * Safe version of huge_pte_offset() to check the locks. See comments * above huge_pte_offset(). diff --git a/mm/hugetlb.c b/mm/hugetlb.c index ba6d39b71cb1..e859fba5bc7d 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -97,6 +97,7 @@ static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma); static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma); static void hugetlb_unshare_pmds(struct vm_area_struct *vma, unsigned long start, unsigned long end); +static struct resv_map *vma_resv_map(struct vm_area_struct *vma); static inline bool subpool_is_free(struct hugepage_subpool *spool) { @@ -267,6 +268,10 @@ void hugetlb_vma_lock_read(struct vm_area_struct *vma) struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; down_read(&vma_lock->rw_sema); + } else if (__vma_private_lock(vma)) { + struct resv_map *resv_map = vma_resv_map(vma); + + down_read(&resv_map->rw_sema); } } @@ -276,6 +281,10 @@ void hugetlb_vma_unlock_read(struct vm_area_struct *vma) struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; up_read(&vma_lock->rw_sema); + } else if (__vma_private_lock(vma)) { + struct resv_map *resv_map = vma_resv_map(vma); + + up_read(&resv_map->rw_sema); } } @@ -285,6 +294,10 @@ void hugetlb_vma_lock_write(struct vm_area_struct *vma) struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; down_write(&vma_lock->rw_sema); + } else if (__vma_private_lock(vma)) { + struct resv_map *resv_map = vma_resv_map(vma); + + down_write(&resv_map->rw_sema); } } @@ -294,17 +307,27 @@ void hugetlb_vma_unlock_write(struct vm_area_struct *vma) struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; up_write(&vma_lock->rw_sema); + } else if (__vma_private_lock(vma)) { + struct resv_map *resv_map = vma_resv_map(vma); + + up_write(&resv_map->rw_sema); } } int hugetlb_vma_trylock_write(struct vm_area_struct *vma) { - struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; - if (!__vma_shareable_lock(vma)) - return 1; + if (__vma_shareable_lock(vma)) { + struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; - return down_write_trylock(&vma_lock->rw_sema); + return down_write_trylock(&vma_lock->rw_sema); + } else if (__vma_private_lock(vma)) { + struct resv_map *resv_map = vma_resv_map(vma); + + return down_write_trylock(&resv_map->rw_sema); + } + + return 1; } void hugetlb_vma_assert_locked(struct vm_area_struct *vma) @@ -313,6 +336,10 @@ void hugetlb_vma_assert_locked(struct vm_area_struct *vma) struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; lockdep_assert_held(&vma_lock->rw_sema); + } else if (__vma_private_lock(vma)) { + struct resv_map *resv_map = vma_resv_map(vma); + + lockdep_assert_held(&resv_map->rw_sema); } } @@ -345,6 +372,11 @@ static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma) struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; __hugetlb_vma_unlock_write_put(vma_lock); + } else { + struct resv_map *resv_map = vma_resv_map(vma); + + /* no free for anon vmas, but still need to unlock */ + up_write(&resv_map->rw_sema); } } @@ -1068,6 +1100,7 @@ struct resv_map *resv_map_alloc(void) kref_init(&resv_map->refs); spin_lock_init(&resv_map->lock); INIT_LIST_HEAD(&resv_map->regions); + init_rwsem(&resv_map->rw_sema); resv_map->adds_in_progress = 0; /*