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x-conformance=sidf_compatible IronPort-SDR: CLOLYOUHQvXdoFD7lyTE5v1cDBjE65rBGAV2R9V1rJiVfyGY3/O4dzzrYzr8GAOf1Qcp9nnobq hyGwySUsf4b8htXabasNAMG3sCdCmdWGB6jTkyYImCEYNG1DuLwwkOup5JZJivdTwQ2ApJVV8K 5zKqxmufGeUFTbZGS6gbGJLmIVPezihhuejUVEKM0KhEgj3EkaY4b66l+yBe7AUgExC/o7SLEQ rKzItvu+MFq+kqyTfLo2z1T2/zYVK814fJLvunWrkT4G4ZwU44TqSelZ6BvgxC3FgOTKQEA+Rl Mrk= X-SBRS: 2.7 X-MesageID: 1880628 X-Ironport-Server: esa4.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.63,388,1557201600"; d="scan'208";a="1880628" From: Paul Durrant To: Anthony Perard Thread-Topic: [PATCH 4/4] xen: Avoid VLA Thread-Index: AQHVJSMYaL9Ko3kp1kKDxJjcc8OjZKagC0EQ///vbYCAAQ/hAA== Date: Tue, 18 Jun 2019 07:50:18 +0000 Message-ID: <424f82301a824e1fb0a140972268fa8f@AMSPEX02CL03.citrite.net> References: <20190617154105.32323-1-anthony.perard@citrix.com> <20190617154105.32323-5-anthony.perard@citrix.com> <20190617173649.GB13449@perard.uk.xensource.com> In-Reply-To: <20190617173649.GB13449@perard.uk.xensource.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: FreeBSD 9.x X-Received-From: 216.71.155.144 Subject: Re: [Qemu-devel] [PATCH 4/4] xen: Avoid VLA 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: "xen-devel@lists.xenproject.org" , Stefano Stabellini , "qemu-devel@nongnu.org" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" > -----Original Message----- > From: Anthony PERARD [mailto:anthony.perard@citrix.com] > Sent: 17 June 2019 18:37 > To: Paul Durrant > Cc: qemu-devel@nongnu.org; xen-devel@lists.xenproject.org; Stefano Stabel= lini > Subject: Re: [PATCH 4/4] xen: Avoid VLA >=20 > On Mon, Jun 17, 2019 at 05:39:09PM +0100, Paul Durrant wrote: > > > @@ -632,6 +633,8 @@ static void xen_sync_dirty_bitmap(XenIOState *sta= te, > > > return; > > > } > > > > > > + bitmap =3D g_new0(unsigned long, bitmap_size); > > > + > > > > How hot is this function? It looks (unsurprisingly) like the section > > size determines the map size so I wonder whether it can instead be > > allocated once when the section is added? >=20 > I think we can store the bitmap buffer into the `state' where > `log_for_dirtybit' is already present, and free the bitmap when > `log_for_dirtybit' is cleared. That sounds better :-) Cheers, Paul >=20 > Thanks, >=20 > -- > Anthony PERARD