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 D2217C147; Thu, 19 Dec 2024 08:55:35 +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=1734598537; cv=none; b=cUqMjnPLyKw19dCknazhp6iw5r07iYSFZxp1U0Z4x6vJOifAdAs4Mv+2XBOlNkEmqsDuFAIaMW/XWCx3ii2kRGDQbyNHy/xfEuNMIEq2YovcO1l3XD0oaHx4R23nc4+XIpFFXBqDeGHmMb9RGwhf0efXXEq/Sw5KQKQ3U0l8yQs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734598537; c=relaxed/simple; bh=7A5q2whs23/ULl9+4Xr7k4cToJx5RL471ktY4u5YHko=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=coCSxG7G2fK0N5AQetByodPNMjDv5qf5pgpCPEXBV0we9VrU0aVaJqlimXZnE9jrXU8eeq+gqQy96vFIrdkzG21EYuDAfHsT1TIyrnpm8zo0K342bMG/1IFgjUzMh7niaPIKuVTqApO62hXnYT3SDfanE9GUTEqeOLy+S9/Uxt0= 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=a4Htox5U; 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="a4Htox5U" 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=ffR6m2ZqxUU9McWLJGVm1c7hM0T9lvoq6tFQ79BnjL0=; b=a4Htox5UDFFhYR64gVjctbvXUY Fi+DPF2oK4+RKQ8IyBDDl3NIuN+Hvl0dreJQhQiV0+kYW8MyO8CbmQ0OrO5nouxyYaZWg7bT+cbzV itK3dPvHpcVTE6DBEwdGlU6ZtQp1ZPh1dgtmpXwzGQLUFF+GUMpBiNMa6kb//ThG5AyZtSiIT34VN hH2Ccw7BFnUY0YMPe1JbK9YxAraNqSYfFfjahhh9rMWixaUS1Cb8+D+KAnRvt06xz6lRSNSoLPHWj kmL9zZ4Qy0n5WYl5v1lWtjj9Zlycb/E2Qj4BzCdRSOn0msZgA0WHd052lTtOka9gX42m7GI292WZO y4/N6e6Q==; 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 1tOCJP-00000002jPo-2NXm; Thu, 19 Dec 2024 08:55:16 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 897BB3003FF; Thu, 19 Dec 2024 09:55:15 +0100 (CET) Date: Thu, 19 Dec 2024 09:55:15 +0100 From: Peter Zijlstra To: Suren Baghdasaryan Cc: "Liam R. Howlett" , akpm@linux-foundation.org, willy@infradead.org, 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: <20241219085515.GB26551@noisy.programming.kicks-ass.net> References: <20241218100601.GI12500@noisy.programming.kicks-ass.net> <20241218161850.GG2354@noisy.programming.kicks-ass.net> <20241218174428.GQ2354@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-kernel@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: On Wed, Dec 18, 2024 at 11:29:23AM -0800, Suren Baghdasaryan wrote: > Yeah, I think we can simply do this: > > vms_complete_munmap_vmas > vms_clear_ptes > remove_vma > vma_mark_detached > mmap_write_downgrade > > If my assumption is incorrect, assertion inside vma_mark_detached() > should trigger. I tried a quick test and so far nothing exploded. I think that would be unfortunate and could cause regressions. I think we want to keep vms_clear_ptes() under the read-lock.