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Tue, 22 Sep 2020 03:16:56 +0000 (UTC) Received: from [10.10.115.46] (ovpn-115-46.rdu2.redhat.com [10.10.115.46]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3E68378827; Tue, 22 Sep 2020 03:16:53 +0000 (UTC) Subject: Re: [RFC][Patch v1 1/3] sched/isolation: API to get num of hosekeeping CPUs To: Frederic Weisbecker Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org, mtosatti@redhat.com, sassmann@redhat.com, jeffrey.t.kirsher@intel.com, jacob.e.keller@intel.com, jlelli@redhat.com, hch@infradead.org, bhelgaas@google.com, mike.marciniszyn@intel.com, dennis.dalessandro@intel.com, thomas.lendacky@amd.com, jerinj@marvell.com, mathias.nyman@intel.com, jiri@nvidia.com References: <20200909150818.313699-1-nitesh@redhat.com> <20200909150818.313699-2-nitesh@redhat.com> <20200921234044.GA31047@lenoir> From: Nitesh Narayan Lal Autocrypt: addr=nitesh@redhat.com; prefer-encrypt=mutual; keydata= mQINBFl4pQoBEADT/nXR2JOfsCjDgYmE2qonSGjkM1g8S6p9UWD+bf7YEAYYYzZsLtbilFTe z4nL4AV6VJmC7dBIlTi3Mj2eymD/2dkKP6UXlliWkq67feVg1KG+4UIp89lFW7v5Y8Muw3Fm uQbFvxyhN8n3tmhRe+ScWsndSBDxYOZgkbCSIfNPdZrHcnOLfA7xMJZeRCjqUpwhIjxQdFA7 n0s0KZ2cHIsemtBM8b2WXSQG9CjqAJHVkDhrBWKThDRF7k80oiJdEQlTEiVhaEDURXq+2XmG jpCnvRQDb28EJSsQlNEAzwzHMeplddfB0vCg9fRk/kOBMDBtGsTvNT9OYUZD+7jaf0gvBvBB lbKmmMMX7uJB+ejY7bnw6ePNrVPErWyfHzR5WYrIFUtgoR3LigKnw5apzc7UIV9G8uiIcZEn C+QJCK43jgnkPcSmwVPztcrkbC84g1K5v2Dxh9amXKLBA1/i+CAY8JWMTepsFohIFMXNLj+B RJoOcR4HGYXZ6CAJa3Glu3mCmYqHTOKwezJTAvmsCLd3W7WxOGF8BbBjVaPjcZfavOvkin0u DaFvhAmrzN6lL0msY17JCZo046z8oAqkyvEflFbC0S1R/POzehKrzQ1RFRD3/YzzlhmIowkM BpTqNBeHEzQAlIhQuyu1ugmQtfsYYq6FPmWMRfFPes/4JUU/PQARAQABtCVOaXRlc2ggTmFy YXlhbiBMYWwgPG5pbGFsQHJlZGhhdC5jb20+iQI9BBMBCAAnBQJZeKUKAhsjBQkJZgGABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheAAAoJEKOGQNwGMqM56lEP/A2KMs/pu0URcVk/kqVwcBhU SnvB8DP3lDWDnmVrAkFEOnPX7GTbactQ41wF/xwjwmEmTzLrMRZpkqz2y9mV0hWHjqoXbOCS 6RwK3ri5e2ThIPoGxFLt6TrMHgCRwm8YuOSJ97o+uohCTN8pmQ86KMUrDNwMqRkeTRW9wWIQ EdDqW44VwelnyPwcmWHBNNb1Kd8j3xKlHtnS45vc6WuoKxYRBTQOwI/5uFpDZtZ1a5kq9Ak/ MOPDDZpd84rqd+IvgMw5z4a5QlkvOTpScD21G3gjmtTEtyfahltyDK/5i8IaQC3YiXJCrqxE r7/4JMZeOYiKpE9iZMtS90t4wBgbVTqAGH1nE/ifZVAUcCtycD0f3egX9CHe45Ad4fsF3edQ ESa5tZAogiA4Hc/yQpnnf43a3aQ67XPOJXxS0Qptzu4vfF9h7kTKYWSrVesOU3QKYbjEAf95 NewF9FhAlYqYrwIwnuAZ8TdXVDYt7Z3z506//sf6zoRwYIDA8RDqFGRuPMXUsoUnf/KKPrtR ceLcSUP/JCNiYbf1/QtW8S6Ca/4qJFXQHp0knqJPGmwuFHsarSdpvZQ9qpxD3FnuPyo64S2N Dfq8TAeifNp2pAmPY2PAHQ3nOmKgMG8Gn5QiORvMUGzSz8Lo31LW58NdBKbh6bci5+t/HE0H pnyVf5xhNC/FuQINBFl4pQoBEACr+MgxWHUP76oNNYjRiNDhaIVtnPRqxiZ9v4H5FPxJy9UD Bqr54rifr1E+K+yYNPt/Po43vVL2cAyfyI/LVLlhiY4yH6T1n+Di/hSkkviCaf13gczuvgz4 KVYLwojU8+naJUsiCJw01MjO3pg9GQ+47HgsnRjCdNmmHiUQqksMIfd8k3reO9SUNlEmDDNB XuSzkHjE5y/R/6p8uXaVpiKPfHoULjNRWaFc3d2JGmxJpBdpYnajoz61m7XJlgwl/B5Ql/6B dHGaX3VHxOZsfRfugwYF9CkrPbyO5PK7yJ5vaiWre7aQ9bmCtXAomvF1q3/qRwZp77k6i9R3 tWfXjZDOQokw0u6d6DYJ0Vkfcwheg2i/Mf/epQl7Pf846G3PgSnyVK6cRwerBl5a68w7xqVU 4KgAh0DePjtDcbcXsKRT9D63cfyfrNE+ea4i0SVik6+N4nAj1HbzWHTk2KIxTsJXypibOKFX 2VykltxutR1sUfZBYMkfU4PogE7NjVEU7KtuCOSAkYzIWrZNEQrxYkxHLJsWruhSYNRsqVBy KvY6JAsq/i5yhVd5JKKU8wIOgSwC9P6mXYRgwPyfg15GZpnw+Fpey4bCDkT5fMOaCcS+vSU1 UaFmC4Ogzpe2BW2DOaPU5Ik99zUFNn6cRmOOXArrryjFlLT5oSOe4IposgWzdwARAQABiQIl BBgBCAAPBQJZeKUKAhsMBQkJZgGAAAoJEKOGQNwGMqM5ELoP/jj9d9gF1Al4+9bngUlYohYu 0sxyZo9IZ7Yb7cHuJzOMqfgoP4tydP4QCuyd9Q2OHHL5AL4VFNb8SvqAxxYSPuDJTI3JZwI7 d8JTPKwpulMSUaJE8ZH9n8A/+sdC3CAD4QafVBcCcbFe1jifHmQRdDrvHV9Es14QVAOTZhnJ vweENyHEIxkpLsyUUDuVypIo6y/Cws+EBCWt27BJi9GH/EOTB0wb+2ghCs/i3h8a+bi+bS7L FCCm/AxIqxRurh2UySn0P/2+2eZvneJ1/uTgfxnjeSlwQJ1BWzMAdAHQO1/lnbyZgEZEtUZJ x9d9ASekTtJjBMKJXAw7GbB2dAA/QmbA+Q+Xuamzm/1imigz6L6sOt2n/X/SSc33w8RJUyor SvAIoG/zU2Y76pKTgbpQqMDmkmNYFMLcAukpvC4ki3Sf086TdMgkjqtnpTkEElMSFJC8npXv 3QnGGOIfFug/qs8z03DLPBz9VYS26jiiN7QIJVpeeEdN/LKnaz5LO+h5kNAyj44qdF2T2AiF HxnZnxO5JNP5uISQH3FjxxGxJkdJ8jKzZV7aT37sC+Rp0o3KNc+GXTR+GSVq87Xfuhx0LRST NK9ZhT0+qkiN7npFLtNtbzwqaqceq3XhafmCiw8xrtzCnlB/C4SiBr/93Ip4kihXJ0EuHSLn VujM7c/b4pps Organization: Red Hat Inc, Message-ID: Date: Mon, 21 Sep 2020 23:16:51 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200921234044.GA31047@lenoir> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=nitesh@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="rWMZpENy2JXtixdCR2Q8UXdNmnZ2CCR0V" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --rWMZpENy2JXtixdCR2Q8UXdNmnZ2CCR0V Content-Type: multipart/mixed; boundary="Yl9iv8fzA3hBXL78rnM0sgz9M6jEuIwcJ" --Yl9iv8fzA3hBXL78rnM0sgz9M6jEuIwcJ Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Language: en-US On 9/21/20 7:40 PM, Frederic Weisbecker wrote: > On Wed, Sep 09, 2020 at 11:08:16AM -0400, Nitesh Narayan Lal wrote: >> +/* >> + * num_housekeeping_cpus() - Read the number of housekeeping CPUs. >> + * >> + * This function returns the number of available housekeeping CPUs >> + * based on __num_housekeeping_cpus which is of type atomic_t >> + * and is initialized at the time of the housekeeping setup. >> + */ >> +unsigned int num_housekeeping_cpus(void) >> +{ >> +=09unsigned int cpus; >> + >> +=09if (static_branch_unlikely(&housekeeping_overridden)) { >> +=09=09cpus =3D atomic_read(&__num_housekeeping_cpus); >> +=09=09/* We should always have at least one housekeeping CPU */ >> +=09=09BUG_ON(!cpus); >> +=09=09return cpus; >> +=09} >> +=09return num_online_cpus(); >> +} >> +EXPORT_SYMBOL_GPL(num_housekeeping_cpus); >> + >> int housekeeping_any_cpu(enum hk_flags flags) >> { >> =09int cpu; >> @@ -131,6 +153,7 @@ static int __init housekeeping_setup(char *str, enum= hk_flags flags) >> =20 >> =09housekeeping_flags |=3D flags; >> =20 >> +=09atomic_set(&__num_housekeeping_cpus, cpumask_weight(housekeeping_mas= k)); > So the problem here is that it takes the whole cpumask weight but you're = only > interested in the housekeepers who take the managed irq duties I guess > (HK_FLAG_MANAGED_IRQ ?). IMHO we should also consider the cases where we only have nohz_full. Otherwise, we may run into the same situation on those setups, do you agree= ? > >> =09free_bootmem_cpumask_var(non_housekeeping_mask); >> =20 >> =09return 1; >> --=20 >> 2.27.0 >> --=20 Thanks Nitesh --Yl9iv8fzA3hBXL78rnM0sgz9M6jEuIwcJ-- --rWMZpENy2JXtixdCR2Q8UXdNmnZ2CCR0V Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEkXcoRVGaqvbHPuAGo4ZA3AYyozkFAl9pbKMACgkQo4ZA3AYy ozlyJBAAsYZ6ty//fnP9eKkhSCXRPQa4F+TiKOYzDEE2rVLrGePTyFeL5myvmzCB tG5o16+rToTlx9SfwaxPUl5Auvc5moKwmRv9eX1+c1l+RF7SlD2gBO53GE+MipuK 58kUg66GmZcc2eonYeJqTCVJCbYQSk24oA3m4nvy+YtzGcDUG6PWsRBrg6U3E55S YG61GlGuHGIURjYxXm2oBoU180B48k5EuR8dSAzz3Isr3TzNwrUHbkgDmlolPs0O myzBgbXDcE+KjRSYF5d1dSO4xUA7F7hTSnWwyKGiSAfHOLFA6omV4IGh1f7TYckA sMPvOWeF7h28TuZYN2N5LfcGu5lboXK+QHjWM0XxZBRVRdLopLTreURNO64yskt2 fmZ1igQDxLRxSnkZSLR42hoGixk2FdPQ/opg/O8/m0SV+7ygphRIYBugFL+FTQiC VDSU5w3k3/mY69fSVDpVBB/KkMVls6VS6qhKYgWDxV2iiEW2Ze7TaUd8jIGNo5Le iz8TuoCQ5rMQB55BK48NOBoF/n9xnskMqhRYqYJqjFdfDghgLsxYtc8vUWSOXfeh DZn6mJ8fHF8KCGJWs5pyZ363QGafJ+V+Z3UBVG52cJBWjQwx+sV4mvrcoIRePOWW KBfLxoxwsec99FCGNJKI32ABYqJfgr1vKHk2IGQDMOxUDrh/WCU= =Hk2/ -----END PGP SIGNATURE----- --rWMZpENy2JXtixdCR2Q8UXdNmnZ2CCR0V--