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 3F14813774B; Thu, 29 Feb 2024 19:37:16 +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=1709235443; cv=none; b=FvAwoAIkQUHv1hCNqD7/4Q0dhPpBkjSj4OHR9IfGZS0wbH2jjGpG4dB/Ir18N15PZWTqKkeX+44vvGporCabw1kjLJ7M5POpQokAe3+7IXDnA85927aVV1R06pMZPFqF3EEnoWCBN2+snJhZaUKmnpIbsEPDlkZdREHmb6Qe+bE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709235443; c=relaxed/simple; bh=32yj74/3vEglgYQz1Og4De9ujIVTdpiMAur4jWBgQXU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=by0vYNNZLE0MOulOGqRAN0E9Z/ulZwWumEca1rd8gwJapHHC7mWbM537Q4KAENkPRT//4uTboAG9bQsnPjj5boukEFaBTZNXJQ9Duk6DrqyQ8ooOMYHSmRM3o6gKu9aSaXLB3O17igFg4Drq2kQCsjNo0pApez5elFA7+J4PA78= 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=LfHiOuS3; 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="LfHiOuS3" 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=8uNmGuKJqG0ZLwvelugqTwty9eAp95ps/IXd1VUbjRE=; b=LfHiOuS377ugSXr21HSPLjoGds rRHRotHB6Z2K+UknnXnK+QSxqb+aTii8MgmSzXW1sRNBptAvRcgkCTNz6J+ZbnsCs2gOL69/7CQwh HbpeH4t5yDhGvqmnlTjCTBFsDyp9akGVrkIGj6y3BedRK3Vygt5msrjSPEYVN6VtIWpZchOzssQ/V WR1aOx0+dyY/SjdSpU3JUwI4U2i/3gjC67frvRbY1ZlyHhnna281LjFJ9s/SzckoOzX+rHWRnRD4q DbfpzdwBNaELy6OKw8HL8OqWb7AQNPVnsIkMg3yiwsLXR6E9Xx/G6dwkxCxOWFcKJ/oDRVozID8PI 7uk/dp4Q==; Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rfmDP-00000008qqb-3bC7; Thu, 29 Feb 2024 19:37:11 +0000 Date: Thu, 29 Feb 2024 19:37:11 +0000 From: Matthew Wilcox To: Greg Edwards Cc: Jens Axboe , Andrew Morton , "Kirill A . Shutemov" , Hugh Dickins , linux-mm@kvack.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, qemu-devel@nongnu.org Subject: Re: [PATCH] block: Remove special-casing of compound pages Message-ID: References: <20230814144100.596749-1-willy@infradead.org> <170198306635.1954272.10907610290128291539.b4-ty@kernel.dk> <20240229182513.GA17355@bobdog.home.arpa> Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20240229182513.GA17355@bobdog.home.arpa> On Thu, Feb 29, 2024 at 11:25:13AM -0700, Greg Edwards wrote: > > [1/1] block: Remove special-casing of compound pages > > commit: 1b151e2435fc3a9b10c8946c6aebe9f3e1938c55 > > This commit results in a change of behavior for QEMU VMs backed by hugepages > that open their VM disk image file with O_DIRECT (QEMU cache=none or > cache.direct=on options). When the VM shuts down and the QEMU process exits, > one or two hugepages may fail to free correctly. It appears to be a race, as > it doesn't happen every time. Hi Greg, By sheer coincidence the very next email after this one was: https://lore.kernel.org/linux-mm/86e592a9-98d4-4cff-a646-0c0084328356@cybernetics.com/T/#u Can you try Tony's patch and see if it fixes your problem? I haven't even begun to analyse either your email or his patch, but there's a strong likelihood that they're the same thing.