From patchwork Tue Oct 1 22:52:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 13818825 X-Patchwork-Delegate: bpf@iogearbox.net Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A0E721CF5D1; Tue, 1 Oct 2024 22:52:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727823142; cv=none; b=J8Tx2s8vzTw6+FV37fePMlf/KJBlOs5dN43d0qRUjVR4s3elTexWVoFiXwAnRIE0y/VhayJlNa4ytl9hOjDtiLDXW0a6Gd2GETdq5u2rfDThhlTBVC0a8u/EurPDC6ksAuNK6ekmZLxgup10fJx6vRrb1rpA+8b1B+jE1EmZqqQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727823142; c=relaxed/simple; bh=Q4lsQ3VDioDbBQhpNH028nIzfuY7M4lO4nHV2LRxuL4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Cic6QzfYFVXNlUWfA+29s3cMa6KcxS0SerYvzOL8rXZyuctL8jJY3HgUOerXFERmTNqEyhGc6Qeri4MzRcxlwHKtZfq6r6QXb7kj9YYOHFAOVnnzG6Nv4bCtxKKwbvHwB1b9q/gp04TB5lJZw1vTMUvS2xf409AxUhlkgC98g2c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=heHmzfSm; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="heHmzfSm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09495C4CECD; Tue, 1 Oct 2024 22:52:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727823142; bh=Q4lsQ3VDioDbBQhpNH028nIzfuY7M4lO4nHV2LRxuL4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=heHmzfSm2yzI1iI9a6pWLMysWPAc4UEw5I9P9k+LCuudPU3BDHrwWOqPAvRSOEqTP Ld0jpPXOtCuEWw1kQnr1yJxZdwUK1sroXcx6QboO6bkoM27/YJj51x4ArDOxWR7e+N 6TroV0+9NlEv+Gi6hpXaHDl9AgN4jyT3NE6il/bVevt/+NknSG3iX/M2eRxc8xAc4x DmsnJVCgep1LiyQEN3aTVQ3r3ZIG1B2qky5sxKLak2lGcIuCEBKb7s+4J8x771Ipfs Y7l+2n+hzxF9xCO4R2/LEb/EF/kjGm7gDDPXvnpTHGN5iCRHxN/cwUM+nhZ1rDPCOl 4im8A0phpKNdQ== From: Andrii Nakryiko To: linux-trace-kernel@vger.kernel.org, peterz@infradead.org, oleg@redhat.com Cc: rostedt@goodmis.org, mhiramat@kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, jolsa@kernel.org, paulmck@kernel.org, willy@infradead.org, surenb@google.com, akpm@linux-foundation.org, linux-mm@kvack.org, mjguzik@gmail.com, brauner@kernel.org, jannh@google.com, mhocko@kernel.org, vbabka@suse.cz, mingo@kernel.org, Andrii Nakryiko Subject: [PATCH v2 tip/perf/core 2/5] mm: switch to 64-bit mm_lock_seq/vm_lock_seq on 64-bit architectures Date: Tue, 1 Oct 2024 15:52:04 -0700 Message-ID: <20241001225207.2215639-3-andrii@kernel.org> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20241001225207.2215639-1-andrii@kernel.org> References: <20241001225207.2215639-1-andrii@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 To increase mm->mm_lock_seq robustness, switch it from int to long, so that it's a 64-bit counter on 64-bit systems and we can stop worrying about it wrapping around in just ~4 billion iterations. Same goes for VMA's matching vm_lock_seq, which is derived from mm_lock_seq. I didn't use __u64 outright to keep 32-bit architectures unaffected, but if it seems important enough, I have nothing against using __u64. Suggested-by: Jann Horn Signed-off-by: Andrii Nakryiko --- include/linux/mm.h | 6 +++--- include/linux/mm_types.h | 4 ++-- include/linux/mmap_lock.h | 4 ++-- 3 files changed, 7 insertions(+), 7 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 6549d0979b28..f8e75d0642a8 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -716,7 +716,7 @@ static inline void vma_end_read(struct vm_area_struct *vma) } /* WARNING! Can only be used if mmap_lock is expected to be write-locked */ -static bool __is_vma_write_locked(struct vm_area_struct *vma, int *mm_lock_seq) +static bool __is_vma_write_locked(struct vm_area_struct *vma, long *mm_lock_seq) { mmap_assert_write_locked(vma->vm_mm); @@ -735,7 +735,7 @@ static bool __is_vma_write_locked(struct vm_area_struct *vma, int *mm_lock_seq) */ static inline void vma_start_write(struct vm_area_struct *vma) { - int mm_lock_seq; + long mm_lock_seq; if (__is_vma_write_locked(vma, &mm_lock_seq)) return; @@ -753,7 +753,7 @@ static inline void vma_start_write(struct vm_area_struct *vma) static inline void vma_assert_write_locked(struct vm_area_struct *vma) { - int mm_lock_seq; + long mm_lock_seq; VM_BUG_ON_VMA(!__is_vma_write_locked(vma, &mm_lock_seq), vma); } diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index d5e3f907eea4..c045543f43d9 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -705,7 +705,7 @@ struct vm_area_struct { * counter reuse can only lead to occasional unnecessary use of the * slowpath. */ - int vm_lock_seq; + long vm_lock_seq; struct vma_lock *vm_lock; #endif @@ -887,7 +887,7 @@ struct mm_struct { * Can be read with ACQUIRE semantics if not holding write * mmap_lock. */ - int mm_lock_seq; + long mm_lock_seq; #endif diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h index 9d23635bc701..fca527dece63 100644 --- a/include/linux/mmap_lock.h +++ b/include/linux/mmap_lock.h @@ -105,7 +105,7 @@ static inline void inc_mm_lock_seq(struct mm_struct *mm, bool acquire) } } -static inline bool mmap_lock_speculation_start(struct mm_struct *mm, int *seq) +static inline bool mmap_lock_speculation_start(struct mm_struct *mm, long *seq) { /* Pairs with RELEASE semantics in inc_mm_lock_seq(). */ *seq = smp_load_acquire(&mm->mm_lock_seq); @@ -113,7 +113,7 @@ static inline bool mmap_lock_speculation_start(struct mm_struct *mm, int *seq) return (*seq & 1) == 0; } -static inline bool mmap_lock_speculation_end(struct mm_struct *mm, int seq) +static inline bool mmap_lock_speculation_end(struct mm_struct *mm, long seq) { /* Pairs with ACQUIRE semantics in inc_mm_lock_seq(). */ smp_rmb();