From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Bader Subject: Question about apic ipi interface Date: Tue, 23 Apr 2013 12:07:18 +0200 Message-ID: <51765D56.1000906@canonical.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1193304443229154873==" Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "xen-devel@lists.xensource.com" , Ben Guthro Cc: Konrad Rzeszutek Wilk List-Id: xen-devel@lists.xenproject.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --===============1193304443229154873== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="------------enig9C059AE4AEFEE2325C0FDEE7" This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig9C059AE4AEFEE2325C0FDEE7 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable I was looking at some older patch and there is one thing I do not underst= and. commit f447d56d36af18c5104ff29dcb1327c0c0ac3634 xen: implement apic ipi interface Specifically there the implementation of xen_send_IPI_mask_allbutself(). void xen_send_IPI_mask_allbutself(const struct cpumask *mask, int vector) { unsigned cpu; unsigned int this_cpu =3D smp_processor_id(); if (!(num_online_cpus() > 1)) return; for_each_cpu_and(cpu, mask, cpu_online_mask) { if (this_cpu =3D=3D cpu) continue; xen_smp_send_call_function_single_ipi(cpu); } } Why is this using xen_smp_send_call_function_single_ipi()? This dumps the= supplied vector and always uses XEN_CALL_FUNCTION_SINGLE_VECTOR. In contr= ast the xen_send_IPI_all() and xen_send_IPI_self() keep the (mapped) vector. Mildly wondering about whether call function would need special casing (j= ust because xen_smp_send_call_function_ipi() is special). But I don't have th= e big picture there. Thanks, Stefan --------------enig9C059AE4AEFEE2325C0FDEE7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iQIcBAEBCgAGBQJRdl1WAAoJEOhnXe7L7s6jcegQAIsTW9wfgK6JSXQpKAPjv08R gJ3AL9AUwd0qzRpX5vpJw/3/P4ABhe+EnnfpTBlTUWNVoflvtxv+2qtezyOAXuVf nuPBwdirmKm6RtZttJktCY3xMf9qgrKmNFXSFn2sTsb7bsgdNgdJLeFCD3mGuTcp pedgEF5UsBxs1x2GUbp3deIm+hjwtuvrMqFQAtL+0kldvtoAyFOcatILsHlm5YxD DCppxtCSGX10oBHG8wqgThA4BfkONYXalKNjfvDLOtT7dBZNmIh+WxUXmAh1s03O vBT9tTR8p53kcCnXiYYBR1Av0Bd5ZF1NyH5Si5I8+HUh4hRXy96N2IE/eUql7A7A uCEkR/0GpvCyYfwJWFxDv7tUuYU949ZhfOgE+9hO3AOfVsAV8woEWYdgJb8mMQ0O RmQg19mpbGrV5RSNDruLPtISv/LIWYFQwloJj7QsdnYsJ7DdqxuNBrMyhXwt4aH8 Cy3aq3aiC8m6De9OBqa8yJIFMm31SH/pRxKPmgcNOyp1vflFuW+0sXtoxXFGiTzO NDmjt99Ltr+18ELGBbs8deWnBo1pnmmc/bi8QCLRhdUcru9M39IeL5Jg7+wNoFuS 0GCORwTP1QN73manPiRXVYyusimPmSsd/NqhWkWmzwLb4GTvooyX5MaRbM290wp6 a4g1P0oR2w7ci49vrmeS =k3+G -----END PGP SIGNATURE----- --------------enig9C059AE4AEFEE2325C0FDEE7-- --===============1193304443229154873== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel --===============1193304443229154873==--