Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Andreas Dilger <adilger@dilger.ca>
Message-Id: <AFE1174E-74AD-4EA3-ADFC-E7512BEC60AE@dilger.ca>
Content-Type: multipart/signed;
 boundary="Apple-Mail=_1B60113F-EF13-4D54-9208-04934C2C0691";
 protocol="application/pgp-signature"; micalg=pgp-sha256
Mime-Version: 1.0 (Mac OS X Mail 10.3 \(3273\))
Subject: Re: [RFCv1 15/72] tst_bitmaps_pthread: Add merge bitmaps test using
 pthreads
Date:   Wed, 14 Dec 2022 14:15:30 -0700
In-Reply-To: <c66b3b734a5a98297728786df5fca21a234d5872.1667822611.git.ritesh.list@gmail.com>
Cc:     Theodore Ts'o <tytso@mit.edu>, linux-ext4@vger.kernel.org,
        Harshad Shirwadkar <harshadshirwadkar@gmail.com>,
        Li Xi <lixi@ddn.com>, Wang Shilong <wangshilong1991@gmail.com>
To:     "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
References: <cover.1667822611.git.ritesh.list@gmail.com>
 <c66b3b734a5a98297728786df5fca21a234d5872.1667822611.git.ritesh.list@gmail.com>
Precedence: bulk


--Apple-Mail=_1B60113F-EF13-4D54-9208-04934C2C0691
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain;
	charset=us-ascii

On Nov 7, 2022, at 5:21 AM, Ritesh Harjani (IBM) <ritesh.list@gmail.com> =
wrote:
>=20
> This patch adds a test to verify the core bitmaps merge APIs
> for rbtree bitmap type.
>=20
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>

Reviewed-by: Andreas Dilger <adilger@dilger.ca>

> +/*
> + * Note we use EXT2FS_BMAP64_BITARRAY always for used_bitmap, this is =
because
> + * EXT2FS_BMAP64_RBTREE does not support parallel scan due to rcursor
> + * optimization.
> + */

Is this going to be a problem in the future?  I think for pass1/pass5 =
there
are no rbtree bitmaps that are *source* bitmaps for multi-threaded =
operation,
but I suspect that once we try to parallelize pass2 this could break.

Is there any check in the code that prevents multi-thread access to an =
rbtree
bitmap?  Making a copy for each thread, or ideally copying the rcursor =
for
each thread, to allow at least multi-threaded reads.  I don't think =
there is
a high need for multi-threaded write

Cheers, Andreas


--Apple-Mail=_1B60113F-EF13-4D54-9208-04934C2C0691
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
	filename=signature.asc
Content-Type: application/pgp-signature;
	name=signature.asc
Content-Description: Message signed with OpenPGP

-----BEGIN PGP SIGNATURE-----
Comment: GPGTools - http://gpgtools.org
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=Mmza
-----END PGP SIGNATURE-----

--Apple-Mail=_1B60113F-EF13-4D54-9208-04934C2C0691--