From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 233501D63C5; Mon, 16 Dec 2024 20:42:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734381771; cv=none; b=rvoyQvk2fjEJ6t5R0VmAkZ2Kkpt54lbEfRDCrlYYrzOlT0j7/xGdOIN30hH7eNxROX89HNED1DeK5yLdhGNpKDtNmYVqJqqGDlbKkWDsGf0AcXwzN88cT9JwEWYzzRi/S+oThqjfJol5zsnEwlLym/sywtMaJFv/iKxOuAxVXyY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734381771; c=relaxed/simple; bh=Wsa0lsfUskZ+wFIP8wYuEeWySF76wctRdDLLa/6PduQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jVRscJLTGmqFpAC0wDCmKN7Xq2WIKCnRnAxA/DqJY5cY6fz5GqH4frg1/J0SC3X9dn2oaFkUDheSGXuI8fzej3R6+oifdWyIj35vDrgT6oxLOM0LrObge7Qtd97UkXzq1hNRJErLx7uZsjL8GooYJ7IylOp434xlxx6OGqoXTdk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=s/weIBr3; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="s/weIBr3" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=XwXXoIySC4SYlAQ92EhSQlV963XBica42YF53fB4Nfc=; b=s/weIBr3ZUWFhT1dOuOQrfM697 EJRBQUsxO1C7C2jT8I47s1sgmmUkhiTjVx7KNRbQAFaAfQj3veI6XexdshyhN3yWkWeGXkhE7ayHt f21vxQqSbrR7oAXleQaXIIyjLJEOz9AwvaJZaoXaxUyAGeOw9Yo9aZlP+RKdUAzhhFerVaY97f+wr VfwtdrxtvqsjD7l9Ojt1J2ntkeg8CWWuI2BbECQx5zh0v7Go8gt5bWinHJEsadpAxvf7ZFGxJrbmn amgAgdvHF73Ir1CyCGPK3Cjd3TlAcNtQms+TGN7N5pEDSF20KunDgCmxukaHCyxFxTaIFfL8vQB7J IWZYbvXA==; Received: from 77-249-17-89.cable.dynamic.v4.ziggo.nl ([77.249.17.89] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tNHv8-00000001vcF-2fiq; Mon, 16 Dec 2024 20:42:26 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 2D82830031E; Mon, 16 Dec 2024 21:42:24 +0100 (CET) Date: Mon, 16 Dec 2024 21:42:23 +0100 From: Peter Zijlstra To: Suren Baghdasaryan Cc: akpm@linux-foundation.org, willy@infradead.org, liam.howlett@oracle.com, lorenzo.stoakes@oracle.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mjguzik@gmail.com, oliver.sang@intel.com, mgorman@techsingularity.net, david@redhat.com, peterx@redhat.com, oleg@redhat.com, dave@stgolabs.net, paulmck@kernel.org, brauner@kernel.org, dhowells@redhat.com, hdanton@sina.com, hughd@google.com, lokeshgidra@google.com, minchan@google.com, jannh@google.com, shakeel.butt@linux.dev, souravpanda@google.com, pasha.tatashin@soleen.com, klarasmodin@gmail.com, corbet@lwn.net, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH v6 10/16] mm: replace vm_lock and detached flag with a reference count Message-ID: <20241216204223.GA9803@noisy.programming.kicks-ass.net> References: <20241216192419.2970941-1-surenb@google.com> <20241216192419.2970941-11-surenb@google.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241216192419.2970941-11-surenb@google.com> On Mon, Dec 16, 2024 at 11:24:13AM -0800, Suren Baghdasaryan wrote: > @@ -734,10 +761,12 @@ static inline bool vma_start_read(struct vm_area_struct *vma) > * after it has been unlocked. > * This pairs with RELEASE semantics in vma_end_write_all(). > */ > + if (oldcnt & VMA_STATE_LOCKED || > + unlikely(vma->vm_lock_seq == raw_read_seqcount(&vma->vm_mm->mm_lock_seq))) { You likely want that unlikely to cover both conditions :-) > + vma_refcount_put(vma); > return false; > } > + > return true; > }