From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jarkko Sakkinen" Subject: Re: [PATCH v4 01/18] cgroup/misc: Add per resource callbacks for CSS events Date: Wed, 13 Sep 2023 12:39:06 +0300 Message-ID: References: <20230913040635.28815-1-haitao.huang@linux.intel.com> <20230913040635.28815-2-haitao.huang@linux.intel.com> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694597951; bh=dSg3FHeMAumbmUvzWNHW95nSf89/Wz3zP7aimaIkbxI=; h=Date:Cc:Subject:From:To:References:In-Reply-To:From; b=ZXzWXrwu9RC5kdgvyD4Ye5Agb5QzVO02jBJEW0mnHaQpEFqlkH9MjuSEVgXaUrJmq EfQzJwDD9BBpXXvndNj+eIkUmIlhnnrBnsgfdmO/sFI5PRoHRFwjrU0y6hxj6aL84H I/1JlDKdOO1LKXWPAMI7ktI9zNLjuHZKAgw7jpbATlCAQIIfwwhGBcxlYjrAwHRiWN 2hlxUuKCUSaDDKSY2Qy6K2Eom2p4u9TlGy9UGMjX9bItwj7Dnlyod7p1U3kbdl/FiD Wu/LBlqhgtKWx1dvr4RG1Rdjsr2CT7nXCgU1y7jqToY0rPbmBIx4XdymwLrsZa4tpi czcohdodFxFCA== In-Reply-To: <20230913040635.28815-2-haitao.huang-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> List-ID: Content-Type: text/plain; charset="us-ascii" To: Haitao Huang , dave.hansen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-sgx-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org, mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org, hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org, sohil.mehta-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org Cc: zhiquan1.li-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, kristen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, zhanb-0li6OtcxBFHby3iVrkZq2A@public.gmane.org, anakrish-0li6OtcxBFHby3iVrkZq2A@public.gmane.org, mikko.ylinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, yangjie-0li6OtcxBFHby3iVrkZq2A@public.gmane.org On Wed Sep 13, 2023 at 7:06 AM EEST, Haitao Huang wrote: > From: Kristen Carlson Accardi > > Consumers of the misc cgroup controller might need to perform separate > actions for Cgroups Subsystem State(CSS) events: cgroup alloc and free. nit: s/State(CSS)/State (CSS)/ "cgroup alloc" and "cgroup free" mean absolutely nothing. > In addition, writes to the max value may also need separate action. Add What "the max value"? > the ability to allow downstream users to setup callbacks for these > operations, and call the corresponding per-resource-type callback when > appropriate. Who are "the downstream users" and what sort of callbacks they setup? > > This code will be utilized by the SGX driver in a future patch. > > Signed-off-by: Kristen Carlson Accardi > Signed-off-by: Haitao Huang > --- > V4: > - Moved this to the front of the series. > - Applies on cgroup/for-6.6 with the overflow fix for misc. > > V3: > - Removed the released() callback > --- > include/linux/misc_cgroup.h | 5 +++++ > kernel/cgroup/misc.c | 32 +++++++++++++++++++++++++++++--- > 2 files changed, 34 insertions(+), 3 deletions(-) > > diff --git a/include/linux/misc_cgroup.h b/include/linux/misc_cgroup.h > index e799b1f8d05b..e1bcd176c2de 100644 > --- a/include/linux/misc_cgroup.h > +++ b/include/linux/misc_cgroup.h > @@ -37,6 +37,11 @@ struct misc_res { > u64 max; > atomic64_t usage; > atomic64_t events; > + > + /* per resource callback ops */ > + int (*misc_cg_alloc)(struct misc_cg *cg); > + void (*misc_cg_free)(struct misc_cg *cg); > + void (*misc_cg_max_write)(struct misc_cg *cg); > }; > =20 > /** > diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c > index 79a3717a5803..e0092170d0dd 100644 > --- a/kernel/cgroup/misc.c > +++ b/kernel/cgroup/misc.c > @@ -276,10 +276,13 @@ static ssize_t misc_cg_max_write(struct kernfs_open= _file *of, char *buf, > =20 > cg =3D css_misc(of_css(of)); > =20 > - if (READ_ONCE(misc_res_capacity[type])) > + if (READ_ONCE(misc_res_capacity[type])) { > WRITE_ONCE(cg->res[type].max, max); > - else > + if (cg->res[type].misc_cg_max_write) > + cg->res[type].misc_cg_max_write(cg); > + } else { > ret =3D -EINVAL; > + } > =20 > return ret ? ret : nbytes; > } > @@ -383,23 +386,39 @@ static struct cftype misc_cg_files[] =3D { > static struct cgroup_subsys_state * > misc_cg_alloc(struct cgroup_subsys_state *parent_css) > { > + struct misc_cg *parent_cg; > enum misc_res_type i; > struct misc_cg *cg; > + int ret; > =20 > if (!parent_css) { > cg =3D &root_cg; > + parent_cg =3D &root_cg; > } else { > cg =3D kzalloc(sizeof(*cg), GFP_KERNEL); > if (!cg) > return ERR_PTR(-ENOMEM); > + parent_cg =3D css_misc(parent_css); > } > =20 > for (i =3D 0; i < MISC_CG_RES_TYPES; i++) { > WRITE_ONCE(cg->res[i].max, MAX_NUM); > atomic64_set(&cg->res[i].usage, 0); > + if (parent_cg->res[i].misc_cg_alloc) { > + ret =3D parent_cg->res[i].misc_cg_alloc(cg); > + if (ret) > + goto alloc_err; > + } > } > =20 > return &cg->css; > + > +alloc_err: > + for (i =3D 0; i < MISC_CG_RES_TYPES; i++) > + if (parent_cg->res[i].misc_cg_free) > + cg->res[i].misc_cg_free(cg); > + kfree(cg); > + return ERR_PTR(ret); > } > =20 > /** > @@ -410,7 +429,14 @@ misc_cg_alloc(struct cgroup_subsys_state *parent_css= ) > */ > static void misc_cg_free(struct cgroup_subsys_state *css) > { > - kfree(css_misc(css)); > + struct misc_cg *cg =3D css_misc(css); > + enum misc_res_type i; > + > + for (i =3D 0; i < MISC_CG_RES_TYPES; i++) > + if (cg->res[i].misc_cg_free) > + cg->res[i].misc_cg_free(cg); > + > + kfree(cg); > } > =20 > /* Cgroup controller callbacks */ > --=20 > 2.25.1 BR, Jarkko