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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <1602524605-481160-10-git-send-email-andrey.shinkevich@virtuozzo.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="QOXOePckLcvR0vJR0EbBf8brVexyLOYOc" Received-SPF: pass client-ip=216.205.24.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/14 01:12:43 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, fam@euphon.net, vsementsov@virtuozzo.com, libvir-list@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com, stefanha@redhat.com, den@openvz.org, jsnow@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --QOXOePckLcvR0vJR0EbBf8brVexyLOYOc Content-Type: multipart/mixed; boundary="0R2X0iT6oiI47Bq90mQu61PJPDmmZ6YqI" --0R2X0iT6oiI47Bq90mQu61PJPDmmZ6YqI Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 12.10.20 19:43, Andrey Shinkevich wrote: > If the flag BDRV_REQ_PREFETCH was set, pass it further to the > COR-driver to skip unneeded reading. It can be taken into account for > the COR-algorithms optimization. That check is being made during the > block stream job by the moment. >=20 > Signed-off-by: Andrey Shinkevich > --- > block/copy-on-read.c | 13 +++++++++---- > block/io.c | 3 ++- > 2 files changed, 11 insertions(+), 5 deletions(-) >=20 > diff --git a/block/copy-on-read.c b/block/copy-on-read.c > index b136895..278a11a 100644 > --- a/block/copy-on-read.c > +++ b/block/copy-on-read.c > @@ -148,10 +148,15 @@ static int coroutine_fn cor_co_preadv_part(BlockDri= verState *bs, > } > } > =20 > - ret =3D bdrv_co_preadv_part(bs->file, offset, n, qiov, qiov_offs= et, > - local_flags); > - if (ret < 0) { > - return ret; > + if (!!(flags & BDRV_REQ_PREFETCH) & How about dropping the double negation and using a logical && instead of the binary &? > + !(local_flags & BDRV_REQ_COPY_ON_READ)) { > + /* Skip non-guest reads if no copy needed */ > + } else { Hm. I would have just written the negated form (!(flags & BDRV_REQ_PREFETCH) || (local_flags & BDRV_REQ_COPY_ON_READ)) and put the =E2=80=9Cskip=E2=80=9D comment above that condition. (Since local_flags is initialized to flags, it can be written as a single comparison, but that=E2=80=99s a matter of taste and I=E2=80=99m not= going to recommend either over the other: ((local_flags & (BDRV_REQ_PREFETCH | BDRV_REQ_COPY_ON_READ)) !=3D BDRV_REQ_PREFETCH) ) > + ret =3D bdrv_co_preadv_part(bs->file, offset, n, qiov, qiov_= offset, > + local_flags); > + if (ret < 0) { > + return ret; > + } > } > =20 > offset +=3D n; > diff --git a/block/io.c b/block/io.c > index 11df188..bff1808 100644 > --- a/block/io.c > +++ b/block/io.c > @@ -1512,7 +1512,8 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChi= ld *child, > =20 > max_bytes =3D ROUND_UP(MAX(0, total_bytes - offset), align); > if (bytes <=3D max_bytes && bytes <=3D max_transfer) { > - ret =3D bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset,= 0); > + ret =3D bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, > + flags & bs->supported_read_flags); Ah, OK. I see. I expected this to be a separate patch. I still wonder why it isn=E2=80=99t. Max > goto out; > } > =20 >=20 --0R2X0iT6oiI47Bq90mQu61PJPDmmZ6YqI-- --QOXOePckLcvR0vJR0EbBf8brVexyLOYOc Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl+G9GUACgkQ9AfbAGHV z0BwKQgAsrnXAK0H8QETjvtqDipGuw21jCLrPbgJbb8d44UKN/BeQgObsGubuNgi oURV2i44f6LdLb/gJ5CBxJvUS03AqkNqffKxbcwHHE7VE0P0FZIqZptv059XAwkO zdMNnMagfLVvLmfXOXznu1/EXBKHQ+G4YIX0TXtjlHOD1RDFrCwnOnmFLF5jgAqL wo3FKKG29V1pnsS9HRvtDrOeyIWWxijDBQVsPzcPLrW+MeBGLdVu5/FeL2RsIaLm uRkws/RXscJwtO54lTqFpgT4FbvJD2gGqhgKuN4Q2I5M0lONZwgRW1TompLQCvNW THvbfqoRt6r9o5Cfip+y/d4vU7ZF8A== =S3VG -----END PGP SIGNATURE----- --QOXOePckLcvR0vJR0EbBf8brVexyLOYOc--