From patchwork Fri Sep 22 19:02:29 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: 143611 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:172:b0:3f2:4152:657d with SMTP id h50csp5815932vqi; Fri, 22 Sep 2023 12:23:17 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHS3wpi+dZLy/7ktjvUyjWod1I5aVLNZFFsUA8qqTI3Ifm18lxEvfUCwsKFlQj5QZ0CDUIk X-Received: by 2002:a17:90b:1d04:b0:274:4b04:392f with SMTP id on4-20020a17090b1d0400b002744b04392fmr544242pjb.24.1695410597686; Fri, 22 Sep 2023 12:23:17 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1695410597; cv=none; d=google.com; s=arc-20160816; b=GOVjLrrY8kza35GfBF9+D8xTLK4Npezqq5BPMXPG6anxg9GVowM30QV0bkaK9mK9sX zqe9k3zs700KK6nRa8RFdIFT0nTp2rISbunOLKSxyiQmZ3iVYc1/q8tABmcBIBiP7XCl mL+86KHLMHfolb394DYgPneuFkhPPgVPe4OKDndFzUxrMwU8wmYxgiedMpXq/rudm/lD /wz8lRvk/7DkweseTCWuzKjHkLAaYa5zS+J3OEybYeOh442EY/NYc/NTZvh+c04u6qRO 7/zPi1BgyXwcKJBK51QrZ/066Ld99AkCtpY34v3Ugtza2KwxR3SVKsaMd9+grZCClXM8 itjw== 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=0txbjbIsHOWecgTF9GBcosacBBIoRx0J1P6iZProGvk=; fh=volCnvwF0JDFbcV4TVnX2BKg6+uih1swgq+cGsuUYCI=; b=KT2kTtcfcW7hJeHufCHzRYltZrMe5fHK91AOW8NqbeDAfHbXmzWK3SxVzM9DS20dUR vCr6UjzHrnfKednFcfCi3MLGkrdPCtoe46wxXM8EXLbgZQw1XToWFG80iRbkCnPECUr2 D2oE168o8WZf3Rf3qKqgVMtJoxUkQP1imsrYCaCtC+3pn72dqF65/7S2fyp5W/AQqd4E UNmtIESCDMc9awuhaeCzsmEDvShQbGzgwyYykccgMTbLmazMxfiPFIbzA4tvVjdoMszg tDIb2wNc5Eho/7jtACayFL8k1TS94wGuoP2gr6vYXCXOgpZbeG8Dri4AABdZGSscN4De /Q7w== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from fry.vger.email (fry.vger.email. [2620:137:e000::3:8]) by mx.google.com with ESMTPS id x7-20020a17090a970700b00273ebc6a4dcsi6474696pjo.121.2023.09.22.12.23.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Sep 2023 12:23:17 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 as permitted sender) client-ip=2620:137:e000::3:8; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 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 fry.vger.email (Postfix) with ESMTP id D4B8683A0B9F; Fri, 22 Sep 2023 12:06:48 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at fry.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233821AbjIVTGj (ORCPT + 28 others); Fri, 22 Sep 2023 15:06:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54854 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233814AbjIVTGf (ORCPT ); Fri, 22 Sep 2023 15:06:35 -0400 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39ECDC2 for ; Fri, 22 Sep 2023 12:06:28 -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 1qjlTP-0002Wy-1W; Fri, 22 Sep 2023 15:05:55 -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: Fri, 22 Sep 2023 15:02:29 -0400 Message-ID: <20230922190552.3963067-2-riel@surriel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230922190552.3963067-1-riel@surriel.com> References: <20230922190552.3963067-1-riel@surriel.com> MIME-Version: 1.0 Sender: riel@surriel.com X-Spam-Status: No, score=2.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_SBL_CSS,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on fry.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 (fry.vger.email [0.0.0.0]); Fri, 22 Sep 2023 12:06:48 -0700 (PDT) X-Spam-Level: ** X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1777766862873226519 X-GMAIL-MSGID: 1777766862873226519 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 --- 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..ee7497f37098 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 if (__vma_private_lock(vma)) { + 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; /* From patchwork Fri Sep 22 19:02:30 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: 143604 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:172:b0:3f2:4152:657d with SMTP id h50csp5811260vqi; Fri, 22 Sep 2023 12:15:01 -0700 (PDT) X-Google-Smtp-Source: AGHT+IE0gRFCoGJrKKgLFRlCiCk9Y+49FCT2tmz4819TzILfcg9lE4eOD/zlmGIClg2TqSt12m0v X-Received: by 2002:a05:6a00:1301:b0:666:e1f4:5153 with SMTP id j1-20020a056a00130100b00666e1f45153mr420392pfu.0.1695410100961; Fri, 22 Sep 2023 12:15:00 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1695410100; cv=none; d=google.com; s=arc-20160816; b=CwwYoH5n/CogIi5tR8mtlvfYufyG/TMomHi2S0qAG3F+aFu7zon4biZqbcJA0eH19y zmEyl1C6OELHaX2humlV6K/ny8pw7FD16i6gfm0fZdZ2JHNVczGIT1WoybZxADCqrqwm aCQXiuZ9gcXK2ayGAbmYWB8/vrYGwliK3HfdUBI7esV+ege6yq05crbTeOJSuJEg91LG H1N4f1+M8fnw7BFb2eGu9raNKqHtMvJCqp+QfOC4uNdt70iETn2+T6UQcLSJozgvnOUg 9bLzAQSHga4vyJ9hSW4fOW0GV9Us3hUXWdfQyn/fvdjY8OPojKXdf/zn/1VzAAig0sqf il3g== ARC-Message-Signature: i=1; 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[23.128.96.35]) by mx.google.com with ESMTPS id f5-20020a056a0022c500b0068fb8704b9csi4716086pfj.28.2023.09.22.12.15.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Sep 2023 12:15:00 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.35 as permitted sender) client-ip=23.128.96.35; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.35 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 groat.vger.email (Postfix) with ESMTP id 0B610812289A; Fri, 22 Sep 2023 12:06:44 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at groat.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233817AbjIVTGf (ORCPT + 28 others); Fri, 22 Sep 2023 15:06:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54846 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233756AbjIVTGe (ORCPT ); Fri, 22 Sep 2023 15:06:34 -0400 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27BCBC1 for ; Fri, 22 Sep 2023 12:06:28 -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 1qjlTP-0002Wy-1k; Fri, 22 Sep 2023 15:05:55 -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 2/3] hugetlbfs: close race between MADV_DONTNEED and page fault Date: Fri, 22 Sep 2023 15:02:30 -0400 Message-ID: <20230922190552.3963067-3-riel@surriel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230922190552.3963067-1-riel@surriel.com> References: <20230922190552.3963067-1-riel@surriel.com> MIME-Version: 1.0 Sender: riel@surriel.com X-Spam-Status: No, score=2.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_SBL_CSS,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on groat.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 (groat.vger.email [0.0.0.0]); Fri, 22 Sep 2023 12:06:44 -0700 (PDT) X-Spam-Level: ** X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1777766341909566476 X-GMAIL-MSGID: 1777766341909566476 From: Rik van Riel Malloc libraries, like jemalloc and tcalloc, take decisions on when to call madvise independently from the code in the main application. This sometimes results in the application page faulting on an address, right after the malloc library has shot down the backing memory with MADV_DONTNEED. Usually this is harmless, because we always have some 4kB pages sitting around to satisfy a page fault. However, with hugetlbfs systems often allocate only the exact number of huge pages that the application wants. Due to TLB batching, hugetlbfs MADV_DONTNEED will free pages outside of any lock taken on the page fault path, which can open up the following race condition: CPU 1 CPU 2 MADV_DONTNEED unmap page shoot down TLB entry page fault fail to allocate a huge page killed with SIGBUS free page Fix that race by pulling the locking from __unmap_hugepage_final_range into helper functions called from zap_page_range_single. This ensures page faults stay locked out of the MADV_DONTNEED VMA until the huge pages have actually been freed. Signed-off-by: Rik van Riel --- include/linux/hugetlb.h | 35 +++++++++++++++++++++++++++++++++-- mm/hugetlb.c | 20 +++++++++++--------- mm/memory.c | 7 +++---- 3 files changed, 47 insertions(+), 15 deletions(-) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 694928fa06a3..d9ec500cfef9 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -139,7 +139,7 @@ struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma, void unmap_hugepage_range(struct vm_area_struct *, unsigned long, unsigned long, struct page *, zap_flags_t); -void __unmap_hugepage_range_final(struct mmu_gather *tlb, +void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long start, unsigned long end, struct page *ref_page, zap_flags_t zap_flags); @@ -246,6 +246,25 @@ int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, unsigned long *start, unsigned long *end); +extern void __hugetlb_zap_begin(struct vm_area_struct *vma, + unsigned long *begin, unsigned long *end); +extern void __hugetlb_zap_end(struct vm_area_struct *vma, + struct zap_details *details); + +static inline void hugetlb_zap_begin(struct vm_area_struct *vma, + unsigned long *start, unsigned long *end) +{ + if (is_vm_hugetlb_page(vma)) + __hugetlb_zap_begin(vma, start, end); +} + +static inline void hugetlb_zap_end(struct vm_area_struct *vma, + struct zap_details *details) +{ + if (is_vm_hugetlb_page(vma)) + __hugetlb_zap_end(vma, details); +} + void hugetlb_vma_lock_read(struct vm_area_struct *vma); void hugetlb_vma_unlock_read(struct vm_area_struct *vma); void hugetlb_vma_lock_write(struct vm_area_struct *vma); @@ -297,6 +316,18 @@ static inline void adjust_range_if_pmd_sharing_possible( { } +static inline void hugetlb_zap_begin( + struct vm_area_struct *vma, + unsigned long *start, unsigned long *end) +{ +} + +static inline void hugetlb_zap_end( + struct vm_area_struct *vma, + struct zap_details *details) +{ +} + static inline struct page *hugetlb_follow_page_mask( struct vm_area_struct *vma, unsigned long address, unsigned int flags, unsigned int *page_mask) @@ -442,7 +473,7 @@ static inline long hugetlb_change_protection( return 0; } -static inline void __unmap_hugepage_range_final(struct mmu_gather *tlb, +static inline void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long start, unsigned long end, struct page *ref_page, zap_flags_t zap_flags) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index ee7497f37098..397a26f70deb 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5306,9 +5306,9 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma, return len + old_addr - old_end; } -static void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, - unsigned long start, unsigned long end, - struct page *ref_page, zap_flags_t zap_flags) +void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, + unsigned long start, unsigned long end, + struct page *ref_page, zap_flags_t zap_flags) { struct mm_struct *mm = vma->vm_mm; unsigned long address; @@ -5435,16 +5435,18 @@ static void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct tlb_flush_mmu_tlbonly(tlb); } -void __unmap_hugepage_range_final(struct mmu_gather *tlb, - struct vm_area_struct *vma, unsigned long start, - unsigned long end, struct page *ref_page, - zap_flags_t zap_flags) +void __hugetlb_zap_begin(struct vm_area_struct *vma, + unsigned long *start, unsigned long *end) { + adjust_range_if_pmd_sharing_possible(vma, start, end); hugetlb_vma_lock_write(vma); i_mmap_lock_write(vma->vm_file->f_mapping); +} - /* mmu notification performed in caller */ - __unmap_hugepage_range(tlb, vma, start, end, ref_page, zap_flags); +void __hugetlb_zap_end(struct vm_area_struct *vma, + struct zap_details *details) +{ + zap_flags_t zap_flags = details ? details->zap_flags : 0; if (zap_flags & ZAP_FLAG_UNMAP) { /* final unmap */ /* diff --git a/mm/memory.c b/mm/memory.c index 6c264d2f969c..a07ae3b60530 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1683,7 +1683,7 @@ static void unmap_single_vma(struct mmu_gather *tlb, if (vma->vm_file) { zap_flags_t zap_flags = details ? details->zap_flags : 0; - __unmap_hugepage_range_final(tlb, vma, start, end, + __unmap_hugepage_range(tlb, vma, start, end, NULL, zap_flags); } } else @@ -1753,9 +1753,7 @@ void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, lru_add_drain(); mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, address, end); - if (is_vm_hugetlb_page(vma)) - adjust_range_if_pmd_sharing_possible(vma, &range.start, - &range.end); + hugetlb_zap_begin(vma, &range.start, &range.end); tlb_gather_mmu(&tlb, vma->vm_mm); update_hiwater_rss(vma->vm_mm); mmu_notifier_invalidate_range_start(&range); @@ -1766,6 +1764,7 @@ void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, unmap_single_vma(&tlb, vma, address, end, details, false); mmu_notifier_invalidate_range_end(&range); tlb_finish_mmu(&tlb); + hugetlb_zap_end(vma, details); } /** From patchwork Fri Sep 22 19:02:31 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: 143612 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:172:b0:3f2:4152:657d with SMTP id h50csp5816005vqi; Fri, 22 Sep 2023 12:23:26 -0700 (PDT) X-Google-Smtp-Source: AGHT+IH1oLjjqaXM332A7akGt/geUFZcg8NP8qxfeqEXeKJWZj8KyNiWUajLUbLExGtuPHrGfchi X-Received: by 2002:a17:902:db0c:b0:1bd:f314:7896 with SMTP id m12-20020a170902db0c00b001bdf3147896mr497007plx.25.1695410606168; Fri, 22 Sep 2023 12:23:26 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1695410606; cv=none; d=google.com; s=arc-20160816; b=Qq3sIDTTMuZPemTmBLAMNWSe09FGJ0ViRfi8ej4uHtFiggxN/OCGEH4bsoa0GHQ9RM 2A6ivGPQci7RjwQq3oQwHMUL+v6tYfAwkVSsDmRfHtd33GwHro2NUhejruTsEP661NsM CxtVDcJaHaRhTzf1O++mjEGWtSEC267EQ9jbETbrJTUrzC6ttoG+KqUER9ZAg+WtlCwS LygzYkpYp2WahZpBL6+nkZpIlmFf5aLzfhOPkqwZvPMHez8Lw8QZf6Se7mhBQPCnhmW4 hfzqZbJARjk/uoS+kUiYZEjPe4a0t+HqMbe5NdwIf3pC6ktAJyVcN9G9fJ/eCrP+c6cZ S4uA== 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=2XDAwHlzRJ8it1VkSH4ryR/v4dHT5od7NJgRxvTxDXs=; fh=volCnvwF0JDFbcV4TVnX2BKg6+uih1swgq+cGsuUYCI=; b=hOPl5GXKS9YWWJpxypY3PIleCC5q5AnSmXQfOhvz7Wpo2VfD2Hb8ob5As3qZMOmMG7 J75G5JeCB+gQw5RAGfvCUhgciGV7/kAzNM8hDUmP9OFSNjsJvUMj0FRY2lI3CGdK2K5f e2fWjkUvTAGcVcW0eFILnziRtoQwpdhUmlu/jPAwEd/K3c//o7JknL4fj36dcXHercZf d9afH3jMVrcZq2imTWxmogLg07smRdiV1zQXGvOrE6Tyl55G4/yaMwUSzhVoUc7277Lg UrXAXDnicH67Jfl8qTZdUdh54d1eB+GNq8GprDUr92kg+fwmE1jVWFxIJNMSGZcBYAPA QDCw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from fry.vger.email (fry.vger.email. [23.128.96.38]) by mx.google.com with ESMTPS id j11-20020a170902da8b00b001c3a2f46800si4642170plx.332.2023.09.22.12.23.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Sep 2023 12:23:26 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 as permitted sender) client-ip=23.128.96.38; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 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 fry.vger.email (Postfix) with ESMTP id B42FC80F72B6; Fri, 22 Sep 2023 12:07:16 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at fry.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233881AbjIVTGo (ORCPT + 28 others); Fri, 22 Sep 2023 15:06:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54960 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229630AbjIVTGi (ORCPT ); Fri, 22 Sep 2023 15:06:38 -0400 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05B31F1 for ; Fri, 22 Sep 2023 12:06:30 -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 1qjlTP-0002Wy-1x; Fri, 22 Sep 2023 15:05:55 -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 3/3] hugetlbfs: replace hugetlb_vma_lock with invalidate_lock Date: Fri, 22 Sep 2023 15:02:31 -0400 Message-ID: <20230922190552.3963067-4-riel@surriel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230922190552.3963067-1-riel@surriel.com> References: <20230922190552.3963067-1-riel@surriel.com> MIME-Version: 1.0 Sender: riel@surriel.com X-Spam-Status: No, score=2.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_SBL_CSS,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on fry.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 (fry.vger.email [0.0.0.0]); Fri, 22 Sep 2023 12:07:16 -0700 (PDT) X-Spam-Level: ** X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1777766871985879684 X-GMAIL-MSGID: 1777766871985879684 From: Rik van Riel Replace the custom hugetlbfs VMA locking code with the recently introduced invalidate_lock. This greatly simplifies things. However, this is a large enough change that it should probably go in separately from the other changes. Suggested-by: Matthew Wilcox Signed-off-by: Rik van Riel --- fs/hugetlbfs/inode.c | 68 +----------- include/linux/fs.h | 6 + include/linux/hugetlb.h | 7 -- kernel/fork.c | 6 - mm/hugetlb.c | 238 +++------------------------------------- 5 files changed, 26 insertions(+), 299 deletions(-) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 316c4cebd3f3..5ff18b0933bc 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -485,7 +485,6 @@ static void hugetlb_unmap_file_folio(struct hstate *h, struct folio *folio, pgoff_t index) { struct rb_root_cached *root = &mapping->i_mmap; - struct hugetlb_vma_lock *vma_lock; struct page *page = &folio->page; struct vm_area_struct *vma; unsigned long v_start; @@ -496,8 +495,8 @@ static void hugetlb_unmap_file_folio(struct hstate *h, end = (index + 1) * pages_per_huge_page(h); i_mmap_lock_write(mapping); -retry: - vma_lock = NULL; + filemap_invalidate_lock(mapping); + vma_interval_tree_foreach(vma, root, start, end - 1) { v_start = vma_offset_start(vma, start); v_end = vma_offset_end(vma, end); @@ -505,62 +504,13 @@ static void hugetlb_unmap_file_folio(struct hstate *h, if (!hugetlb_vma_maps_page(vma, v_start, page)) continue; - if (!hugetlb_vma_trylock_write(vma)) { - vma_lock = vma->vm_private_data; - /* - * If we can not get vma lock, we need to drop - * immap_sema and take locks in order. First, - * take a ref on the vma_lock structure so that - * we can be guaranteed it will not go away when - * dropping immap_sema. - */ - kref_get(&vma_lock->refs); - break; - } - unmap_hugepage_range(vma, v_start, v_end, NULL, ZAP_FLAG_DROP_MARKER); hugetlb_vma_unlock_write(vma); } + filemap_invalidate_unlock(mapping); i_mmap_unlock_write(mapping); - - if (vma_lock) { - /* - * Wait on vma_lock. We know it is still valid as we have - * a reference. We must 'open code' vma locking as we do - * not know if vma_lock is still attached to vma. - */ - down_write(&vma_lock->rw_sema); - i_mmap_lock_write(mapping); - - vma = vma_lock->vma; - if (!vma) { - /* - * If lock is no longer attached to vma, then just - * unlock, drop our reference and retry looking for - * other vmas. - */ - up_write(&vma_lock->rw_sema); - kref_put(&vma_lock->refs, hugetlb_vma_lock_release); - goto retry; - } - - /* - * vma_lock is still attached to vma. Check to see if vma - * still maps page and if so, unmap. - */ - v_start = vma_offset_start(vma, start); - v_end = vma_offset_end(vma, end); - if (hugetlb_vma_maps_page(vma, v_start, page)) - unmap_hugepage_range(vma, v_start, v_end, NULL, - ZAP_FLAG_DROP_MARKER); - - kref_put(&vma_lock->refs, hugetlb_vma_lock_release); - hugetlb_vma_unlock_write(vma); - - goto retry; - } } static void @@ -578,20 +528,10 @@ hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end, unsigned long v_start; unsigned long v_end; - if (!hugetlb_vma_trylock_write(vma)) - continue; - v_start = vma_offset_start(vma, start); v_end = vma_offset_end(vma, end); unmap_hugepage_range(vma, v_start, v_end, NULL, zap_flags); - - /* - * Note that vma lock only exists for shared/non-private - * vmas. Therefore, lock is not held when calling - * unmap_hugepage_range for private vmas. - */ - hugetlb_vma_unlock_write(vma); } } @@ -726,9 +666,11 @@ static void hugetlb_vmtruncate(struct inode *inode, loff_t offset) i_size_write(inode, offset); i_mmap_lock_write(mapping); + filemap_invalidate_lock(mapping); if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)) hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0, ZAP_FLAG_DROP_MARKER); + filemap_invalidate_unlock(mapping); i_mmap_unlock_write(mapping); remove_inode_hugepages(inode, offset, LLONG_MAX); } diff --git a/include/linux/fs.h b/include/linux/fs.h index 4aeb3fa11927..b455a8913db4 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -847,6 +847,12 @@ static inline void filemap_invalidate_lock(struct address_space *mapping) down_write(&mapping->invalidate_lock); } +static inline int filemap_invalidate_trylock( + struct address_space *mapping) +{ + return down_write_trylock(&mapping->invalidate_lock); +} + static inline void filemap_invalidate_unlock(struct address_space *mapping) { up_write(&mapping->invalidate_lock); diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index d9ec500cfef9..af60b67ed828 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -60,7 +60,6 @@ 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 @@ -107,12 +106,6 @@ struct file_region { #endif }; -struct hugetlb_vma_lock { - struct kref refs; - struct rw_semaphore rw_sema; - struct vm_area_struct *vma; -}; - extern struct resv_map *resv_map_alloc(void); void resv_map_release(struct kref *ref); diff --git a/kernel/fork.c b/kernel/fork.c index 3b6d20dfb9a8..42453437b615 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -743,12 +743,6 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, i_mmap_unlock_write(mapping); } - /* - * Copy/update hugetlb private vma information. - */ - if (is_vm_hugetlb_page(tmp)) - hugetlb_dup_vma_private(tmp); - /* Link the vma into the MT */ if (vma_iter_bulk_store(&vmi, tmp)) goto fail_nomem_vmi_store; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 397a26f70deb..3b97bd762049 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -92,9 +92,6 @@ struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp; /* Forward declaration */ static int hugetlb_acct_memory(struct hstate *h, long delta); -static void hugetlb_vma_lock_free(struct vm_area_struct *vma); -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); @@ -264,170 +261,41 @@ static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma) */ void hugetlb_vma_lock_read(struct vm_area_struct *vma) { - if (__vma_shareable_lock(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); - } + if (vma->vm_file) + filemap_invalidate_lock_shared(vma->vm_file->f_mapping); } void hugetlb_vma_unlock_read(struct vm_area_struct *vma) { - if (__vma_shareable_lock(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); - } + if (vma->vm_file) + filemap_invalidate_unlock_shared(vma->vm_file->f_mapping); } void hugetlb_vma_lock_write(struct vm_area_struct *vma) { - if (__vma_shareable_lock(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); - } + if (vma->vm_file) + filemap_invalidate_lock(vma->vm_file->f_mapping); } void hugetlb_vma_unlock_write(struct vm_area_struct *vma) { - if (__vma_shareable_lock(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); - } + if (vma->vm_file) + filemap_invalidate_unlock(vma->vm_file->f_mapping); } int hugetlb_vma_trylock_write(struct vm_area_struct *vma) { - if (__vma_shareable_lock(vma)) { - struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; - - 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); - } + if (vma->vm_file) + return filemap_invalidate_trylock(vma->vm_file->f_mapping); return 1; } void hugetlb_vma_assert_locked(struct vm_area_struct *vma) { - if (__vma_shareable_lock(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); - } -} - -void hugetlb_vma_lock_release(struct kref *kref) -{ - struct hugetlb_vma_lock *vma_lock = container_of(kref, - struct hugetlb_vma_lock, refs); - - kfree(vma_lock); -} - -static void __hugetlb_vma_unlock_write_put(struct hugetlb_vma_lock *vma_lock) -{ - struct vm_area_struct *vma = vma_lock->vma; - - /* - * vma_lock structure may or not be released as a result of put, - * it certainly will no longer be attached to vma so clear pointer. - * Semaphore synchronizes access to vma_lock->vma field. - */ - vma_lock->vma = NULL; - vma->vm_private_data = NULL; - up_write(&vma_lock->rw_sema); - kref_put(&vma_lock->refs, hugetlb_vma_lock_release); -} - -static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma) -{ - if (__vma_shareable_lock(vma)) { - struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; - - __hugetlb_vma_unlock_write_put(vma_lock); - } else if (__vma_private_lock(vma)) { - 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); - } -} - -static void hugetlb_vma_lock_free(struct vm_area_struct *vma) -{ - /* - * Only present in sharable vmas. - */ - if (!vma || !__vma_shareable_lock(vma)) - return; - - if (vma->vm_private_data) { - struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; - - down_write(&vma_lock->rw_sema); - __hugetlb_vma_unlock_write_put(vma_lock); - } -} - -static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma) -{ - struct hugetlb_vma_lock *vma_lock; - - /* Only establish in (flags) sharable vmas */ - if (!vma || !(vma->vm_flags & VM_MAYSHARE)) - return; - - /* Should never get here with non-NULL vm_private_data */ - if (vma->vm_private_data) - return; - - vma_lock = kmalloc(sizeof(*vma_lock), GFP_KERNEL); - if (!vma_lock) { - /* - * If we can not allocate structure, then vma can not - * participate in pmd sharing. This is only a possible - * performance enhancement and memory saving issue. - * However, the lock is also used to synchronize page - * faults with truncation. If the lock is not present, - * unlikely races could leave pages in a file past i_size - * until the file is removed. Warn in the unlikely case of - * allocation failure. - */ - pr_warn_once("HugeTLB: unable to allocate vma specific lock\n"); - return; - } - - kref_init(&vma_lock->refs); - init_rwsem(&vma_lock->rw_sema); - vma_lock->vma = vma; - vma->vm_private_data = vma_lock; + if (vma->vm_file) + lockdep_assert_held(&vma->vm_file->f_mapping->invalidate_lock); } /* Helper that removes a struct file_region from the resv_map cache and returns @@ -1100,7 +968,6 @@ 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; /* @@ -1190,30 +1057,6 @@ static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) return (get_vma_private_data(vma) & flag) != 0; } -void hugetlb_dup_vma_private(struct vm_area_struct *vma) -{ - VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); - /* - * Clear vm_private_data - * - For shared mappings this is a per-vma semaphore that may be - * allocated in a subsequent call to hugetlb_vm_op_open. - * Before clearing, make sure pointer is not associated with vma - * as this will leak the structure. This is the case when called - * via clear_vma_resv_huge_pages() and hugetlb_vm_op_open has already - * been called to allocate a new structure. - * - For MAP_PRIVATE mappings, this is the reserve map which does - * not apply to children. Faults generated by the children are - * not guaranteed to succeed, even if read-only. - */ - if (vma->vm_flags & VM_MAYSHARE) { - struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; - - if (vma_lock && vma_lock->vma != vma) - vma->vm_private_data = NULL; - } else - vma->vm_private_data = NULL; -} - /* * Reset and decrement one ref on hugepage private reservation. * Called with mm->mmap_lock writer semaphore held. @@ -1241,8 +1084,6 @@ void clear_vma_resv_huge_pages(struct vm_area_struct *vma) resv_map_put_hugetlb_cgroup_uncharge_info(reservations); kref_put(&reservations->refs, resv_map_release); } - - hugetlb_dup_vma_private(vma); } /* Returns true if the VMA has associated reserve pages */ @@ -4846,25 +4687,6 @@ static void hugetlb_vm_op_open(struct vm_area_struct *vma) resv_map_dup_hugetlb_cgroup_uncharge_info(resv); kref_get(&resv->refs); } - - /* - * vma_lock structure for sharable mappings is vma specific. - * Clear old pointer (if copied via vm_area_dup) and allocate - * new structure. Before clearing, make sure vma_lock is not - * for this vma. - */ - if (vma->vm_flags & VM_MAYSHARE) { - struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; - - if (vma_lock) { - if (vma_lock->vma != vma) { - vma->vm_private_data = NULL; - hugetlb_vma_lock_alloc(vma); - } else - pr_warn("HugeTLB: vma_lock already exists in %s.\n", __func__); - } else - hugetlb_vma_lock_alloc(vma); - } } static void hugetlb_vm_op_close(struct vm_area_struct *vma) @@ -4875,8 +4697,6 @@ static void hugetlb_vm_op_close(struct vm_area_struct *vma) unsigned long reserve, start, end; long gbl_reserve; - hugetlb_vma_lock_free(vma); - resv = vma_resv_map(vma); if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER)) return; @@ -5446,24 +5266,8 @@ void __hugetlb_zap_begin(struct vm_area_struct *vma, void __hugetlb_zap_end(struct vm_area_struct *vma, struct zap_details *details) { - zap_flags_t zap_flags = details ? details->zap_flags : 0; - - if (zap_flags & ZAP_FLAG_UNMAP) { /* final unmap */ - /* - * Unlock and free the vma lock before releasing i_mmap_rwsem. - * When the vma_lock is freed, this makes the vma ineligible - * for pmd sharing. And, i_mmap_rwsem is required to set up - * pmd sharing. This is important as page tables for this - * unmapped range will be asynchrously deleted. If the page - * tables are shared, there will be issues when accessed by - * someone else. - */ - __hugetlb_vma_unlock_write_free(vma); - i_mmap_unlock_write(vma->vm_file->f_mapping); - } else { - i_mmap_unlock_write(vma->vm_file->f_mapping); - hugetlb_vma_unlock_write(vma); - } + i_mmap_unlock_write(vma->vm_file->f_mapping); + hugetlb_vma_unlock_write(vma); } void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, @@ -6706,12 +6510,6 @@ bool hugetlb_reserve_pages(struct inode *inode, return false; } - /* - * vma specific semaphore used for pmd sharing and fault/truncation - * synchronization - */ - hugetlb_vma_lock_alloc(vma); - /* * Only apply hugepage reservation if asked. At fault time, an * attempt will be made for VM_NORESERVE to allocate a page @@ -6834,7 +6632,6 @@ bool hugetlb_reserve_pages(struct inode *inode, hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h), chg * pages_per_huge_page(h), h_cg); out_err: - hugetlb_vma_lock_free(vma); if (!vma || vma->vm_flags & VM_MAYSHARE) /* Only call region_abort if the region_chg succeeded but the * region_add failed or didn't run. @@ -6904,13 +6701,10 @@ static unsigned long page_table_shareable(struct vm_area_struct *svma, /* * match the virtual addresses, permission and the alignment of the * page table page. - * - * Also, vma_lock (vm_private_data) is required for sharing. */ if (pmd_index(addr) != pmd_index(saddr) || vm_flags != svm_flags || - !range_in_vma(svma, sbase, s_end) || - !svma->vm_private_data) + !range_in_vma(svma, sbase, s_end)) return 0; return saddr; @@ -6930,8 +6724,6 @@ bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr) */ if (!(vma->vm_flags & VM_MAYSHARE)) return false; - if (!vma->vm_private_data) /* vma lock required for sharing */ - return false; if (!range_in_vma(vma, start, end)) return false; return true;