From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lamorak.hansenpartnership.com (lamorak.hansenpartnership.com [198.37.111.173]) (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 E8856217712; Thu, 27 Mar 2025 14:28:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.37.111.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743085719; cv=none; b=nqaTVq6hkGMVd19a1ayxyl51COQNgv1EMkmbYbhdv+l23Jbv+Pgu33ev24EHveqvKT4LLWn7SeeyGLOEKP6KE35x41gpZpzUy2ba0xUgRBDbetnVdcHW3P4tQV+VwQnF8AWl5qUeQFs1VrvJE9w0KVi8of4z1KvdBaG8oZXM884= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743085719; c=relaxed/simple; bh=S9jwIxMJ7ADjGqwBshFgWpc8tOTHgEevVJV2KY9MSUY=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=iQXHgzfbEnOx9WkLruSUG7oTRJNcfOfEovi5VJXAjYQgmLZz7kI9zpdTU8pgYk+b6vBGd+FY/PufHy9D5o13fpfljIX12Xbtx893ejECiJyhaZhrVzSIMDwEXq9WHJqmKYHI5Tslqc7C/vzrDebGUL8ifds0w/8LT3ZrD0DRdQI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com; spf=pass smtp.mailfrom=HansenPartnership.com; dkim=pass (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b=H4javcJW; arc=none smtp.client-ip=198.37.111.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=HansenPartnership.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="H4javcJW" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hansenpartnership.com; s=20151216; t=1743085716; bh=S9jwIxMJ7ADjGqwBshFgWpc8tOTHgEevVJV2KY9MSUY=; h=Message-ID:Subject:From:To:Date:In-Reply-To:References:From; b=H4javcJW7G0NvM3/ajRZ9SIRnys+zjPhKxtqd+mlDoCtuxWm08IASm4fqDRx1pkgi RNTQhIAmfDBl/4w07u6sM41smyVTQ5gVYW7URvC08M2DjGBV89t5Qr4RZAs+RWG0G6 uqZnoiQ8fpGtKgaZvoyEcRfv7bS87CidhEc8VtJQ= Received: from [172.20.0.78] (unknown [99.209.85.25]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lamorak.hansenpartnership.com (Postfix) with ESMTPSA id 76C4F1C02ED; Thu, 27 Mar 2025 10:28:36 -0400 (EDT) Message-ID: <25f2c7dd471077d816ad29e461c6d762921927e1.camel@HansenPartnership.com> Subject: Re: [Lsf-pc] [LSF/MM/BPF TOPIC] Filesystem Suspend Resume From: James Bottomley To: Jan Kara Cc: Dave Chinner , Christoph Hellwig , linux-fsdevel@vger.kernel.org, lsf-pc@lists.linux-foundation.org, "Rafael J. Wysocki" , Pavel Machek , Len Brown , linux-pm@vger.kernel.org Date: Thu, 27 Mar 2025 10:28:35 -0400 In-Reply-To: <45d6ff00d8068ee87ccc396ae28c7931b8c3306c.camel@HansenPartnership.com> References: <576418420308d2511a4c155cc57cf0b1420c273b.camel@HansenPartnership.com> <62bfd49bc06a58e435431610256e722651e1e5ca.camel@HansenPartnership.com> <7f3eddf89f8fd128ffeb643bc582e45a7d13c216.camel@HansenPartnership.com> <1af829aa7a65eb5ebc0614a00f7019615ed0f62b.camel@HansenPartnership.com> <45d6ff00d8068ee87ccc396ae28c7931b8c3306c.camel@HansenPartnership.com> Autocrypt: addr=James.Bottomley@HansenPartnership.com; prefer-encrypt=mutual; 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8mT2Eh9SkH+YVOmaKsajgZgrBxA7fWmGoxXswEVxJIFj3vW7yNc0C5HaUdYa5iGOMs4kg2ht4s7yy7NRQuh7BifWjo6BQ6k4S1H+6axZucxhSV1L6zN9d+lr3Xo/vy1unzA== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.3 Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2025-03-26 at 11:25 -0400, James Bottomley wrote: > On Wed, 2025-03-26 at 15:59 +0100, Jan Kara wrote: > [...] > > So to summarize I think we may need to introduce freezable variant > > of > > percpu_rwsem_down_read() and use it in sb_start_write(). >=20 > Aye, aye, sir! and thanks for making the can of worms bigger ... >=20 > This is what I came up with for freezable variants of the > sb_write_start().=C2=A0 I'm still building the kernel (laptop only ...) s= o > I'll let you know in an hour or so if it actually works. Slightly longer than an hour, but I can confirm this all works. I've also tested it with filesystem on loop on filesystem (with ext4 as upper and lower) and it hibernates just fine running some fio stress. I've posted what I'm currently working with here: https://lore.kernel.org/all/20250327140613.25178-1-James.Bottomley@HansenPa= rtnership.com/ So people can see what I'm currently playing with. Regards, James