From: Tejun Heo <tj@kernel.org>
To: torvalds@linux-foundation.org, mingo@redhat.com,
peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
bristot@redhat.com, vschneid@redhat.com, ast@kernel.org,
daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org,
joshdon@google.com, brho@google.com, pjt@google.com,
derkling@google.com, haoluo@google.com, dvernet@meta.com,
dschatzberg@meta.com, dskarlat@cs.cmu.edu, riel@surriel.com,
changwoo@igalia.com, himadrics@inria.fr, memxor@gmail.com
Cc: linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
kernel-team@meta.com, Tejun Heo <tj@kernel.org>
Subject: [PATCH 06/36] sched: Factor out cgroup weight conversion functions
Date: Fri, 10 Nov 2023 16:47:32 -1000 [thread overview]
Message-ID: <20231111024835.2164816-7-tj@kernel.org> (raw)
In-Reply-To: <20231111024835.2164816-1-tj@kernel.org>
Factor out sched_weight_from/to_cgroup() which convert between scheduler
shares and cgroup weight. No functional change. The factored out functions
will be used by a new BPF extensible sched_class so that the weights can be
exposed to the BPF programs in a way which is consistent cgroup weights and
easier to interpret.
The weight conversions will be used regardless of cgroup usage. It's just
borrowing the cgroup weight range as it's more intuitive.
CGROUP_WEIGHT_MIN/DFL/MAX constants are moved outside CONFIG_CGROUPS so that
the conversion helpers can always be defined.
v2: The helpers are now defined regardless of COFNIG_CGROUPS.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: David Vernet <dvernet@meta.com>
Acked-by: Josh Don <joshdon@google.com>
Acked-by: Hao Luo <haoluo@google.com>
Acked-by: Barret Rhoden <brho@google.com>
---
include/linux/cgroup.h | 4 ++--
kernel/sched/core.c | 28 +++++++++++++---------------
kernel/sched/sched.h | 18 ++++++++++++++++++
3 files changed, 33 insertions(+), 17 deletions(-)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index d164eaeacfa6..53040f7464c4 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -29,8 +29,6 @@
struct kernel_clone_args;
-#ifdef CONFIG_CGROUPS
-
/*
* All weight knobs on the default hierarchy should use the following min,
* default and max values. The default value is the logarithmic center of
@@ -40,6 +38,8 @@ struct kernel_clone_args;
#define CGROUP_WEIGHT_DFL 100
#define CGROUP_WEIGHT_MAX 10000
+#ifdef CONFIG_CGROUPS
+
enum {
CSS_TASK_ITER_PROCS = (1U << 0), /* walk only threadgroup leaders */
CSS_TASK_ITER_THREADED = (1U << 1), /* walk all threaded css_sets in the domain */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 26ad5dc65ede..05131ad4b5d5 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -11267,29 +11267,27 @@ static int cpu_local_stat_show(struct seq_file *sf,
}
#ifdef CONFIG_FAIR_GROUP_SCHED
+
+static unsigned long tg_weight(struct task_group *tg)
+{
+ return scale_load_down(tg->shares);
+}
+
static u64 cpu_weight_read_u64(struct cgroup_subsys_state *css,
struct cftype *cft)
{
- struct task_group *tg = css_tg(css);
- u64 weight = scale_load_down(tg->shares);
-
- return DIV_ROUND_CLOSEST_ULL(weight * CGROUP_WEIGHT_DFL, 1024);
+ return sched_weight_to_cgroup(tg_weight(css_tg(css)));
}
static int cpu_weight_write_u64(struct cgroup_subsys_state *css,
- struct cftype *cft, u64 weight)
+ struct cftype *cft, u64 cgrp_weight)
{
- /*
- * cgroup weight knobs should use the common MIN, DFL and MAX
- * values which are 1, 100 and 10000 respectively. While it loses
- * a bit of range on both ends, it maps pretty well onto the shares
- * value used by scheduler and the round-trip conversions preserve
- * the original value over the entire range.
- */
- if (weight < CGROUP_WEIGHT_MIN || weight > CGROUP_WEIGHT_MAX)
+ unsigned long weight;
+
+ if (cgrp_weight < CGROUP_WEIGHT_MIN || cgrp_weight > CGROUP_WEIGHT_MAX)
return -ERANGE;
- weight = DIV_ROUND_CLOSEST_ULL(weight * 1024, CGROUP_WEIGHT_DFL);
+ weight = sched_weight_from_cgroup(cgrp_weight);
return sched_group_set_shares(css_tg(css), scale_load(weight));
}
@@ -11297,7 +11295,7 @@ static int cpu_weight_write_u64(struct cgroup_subsys_state *css,
static s64 cpu_weight_nice_read_s64(struct cgroup_subsys_state *css,
struct cftype *cft)
{
- unsigned long weight = scale_load_down(css_tg(css)->shares);
+ unsigned long weight = tg_weight(css_tg(css));
int last_delta = INT_MAX;
int prio, delta;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index bfe7303559f1..a6d073a56c2d 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -221,6 +221,24 @@ static inline void update_avg(u64 *avg, u64 sample)
#define shr_bound(val, shift) \
(val >> min_t(typeof(shift), shift, BITS_PER_TYPE(typeof(val)) - 1))
+/*
+ * cgroup weight knobs should use the common MIN, DFL and MAX values which are
+ * 1, 100 and 10000 respectively. While it loses a bit of range on both ends, it
+ * maps pretty well onto the shares value used by scheduler and the round-trip
+ * conversions preserve the original value over the entire range.
+ */
+static inline unsigned long sched_weight_from_cgroup(unsigned long cgrp_weight)
+{
+ return DIV_ROUND_CLOSEST_ULL(cgrp_weight * 1024, CGROUP_WEIGHT_DFL);
+}
+
+static inline unsigned long sched_weight_to_cgroup(unsigned long weight)
+{
+ return clamp_t(unsigned long,
+ DIV_ROUND_CLOSEST_ULL(weight * CGROUP_WEIGHT_DFL, 1024),
+ CGROUP_WEIGHT_MIN, CGROUP_WEIGHT_MAX);
+}
+
/*
* !! For sched_setattr_nocheck() (kernel) only !!
*
--
2.42.0
next prev parent reply other threads:[~2023-11-11 2:49 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-11 2:47 [PATCHSET v5] sched: Implement BPF extensible scheduler class Tejun Heo
2023-11-11 2:47 ` [PATCH 01/36] cgroup: Implement cgroup_show_cftypes() Tejun Heo
2023-11-11 2:47 ` [PATCH 02/36] sched: Restructure sched_class order sanity checks in sched_init() Tejun Heo
2023-11-11 2:47 ` [PATCH 03/36] sched: Allow sched_cgroup_fork() to fail and introduce sched_cancel_fork() Tejun Heo
2023-11-11 2:47 ` [PATCH 04/36] sched: Add sched_class->reweight_task() Tejun Heo
2023-11-11 2:47 ` [PATCH 05/36] sched: Add sched_class->switching_to() and expose check_class_changing/changed() Tejun Heo
2023-11-11 2:47 ` Tejun Heo [this message]
2023-11-11 2:47 ` [PATCH 07/36] sched: Expose css_tg() and __setscheduler_prio() Tejun Heo
2023-11-11 2:47 ` [PATCH 08/36] sched: Enumerate CPU cgroup file types Tejun Heo
2023-11-11 2:47 ` [PATCH 09/36] sched: Add @reason to sched_class->rq_{on|off}line() Tejun Heo
2023-11-11 2:47 ` [PATCH 10/36] sched: Add normal_policy() Tejun Heo
2023-11-11 2:47 ` [PATCH 11/36] sched_ext: Add boilerplate for extensible scheduler class Tejun Heo
2023-11-11 2:47 ` [PATCH 12/36] sched_ext: Implement BPF " Tejun Heo
2023-11-13 13:34 ` Changwoo Min
2023-11-14 19:07 ` Tejun Heo
2023-11-13 20:04 ` Andrea Righi
2023-11-14 19:07 ` Tejun Heo
2023-11-23 8:07 ` Andrea Righi
2023-11-25 19:59 ` Tejun Heo
2023-11-26 9:05 ` Andrea Righi
2023-12-07 2:04 ` [PATCH] scx: set p->scx.ops_state using atomic_long_set_release Changwoo Min
2023-12-08 0:16 ` Tejun Heo
2024-03-23 2:37 ` [PATCH 12/36] sched_ext: Implement BPF extensible scheduler class Joel Fernandes
2024-03-23 22:12 ` Tejun Heo
2024-04-25 21:28 ` Joel Fernandes
2024-04-26 16:57 ` Barret Rhoden
2024-04-26 21:58 ` Tejun Heo
2023-11-11 2:47 ` [PATCH 13/36] sched_ext: Add scx_simple and scx_example_qmap example schedulers Tejun Heo
2023-11-12 4:17 ` kernel test robot
2023-11-12 18:06 ` Tejun Heo
2023-11-11 2:47 ` [PATCH 14/36] sched_ext: Add sysrq-S which disables the BPF scheduler Tejun Heo
2023-11-11 2:47 ` [PATCH 15/36] sched_ext: Implement runnable task stall watchdog Tejun Heo
2023-11-11 2:47 ` [PATCH 16/36] sched_ext: Allow BPF schedulers to disallow specific tasks from joining SCHED_EXT Tejun Heo
2023-11-11 2:47 ` [PATCH 17/36] sched_ext: Allow BPF schedulers to switch all eligible tasks into sched_ext Tejun Heo
2023-11-11 2:47 ` [PATCH 18/36] sched_ext: Print sched_ext info when dumping stack Tejun Heo
2023-11-14 19:23 ` [PATCH v2 " Tejun Heo
2023-11-11 2:47 ` [PATCH 19/36] sched_ext: Implement scx_bpf_kick_cpu() and task preemption support Tejun Heo
2023-11-11 2:47 ` [PATCH 20/36] sched_ext: Add a central scheduler which makes all scheduling decisions on one CPU Tejun Heo
2023-11-11 2:47 ` [PATCH 21/36] sched_ext: Make watchdog handle ops.dispatch() looping stall Tejun Heo
2023-11-11 2:47 ` [PATCH 22/36] sched_ext: Add task state tracking operations Tejun Heo
2023-11-11 2:47 ` [PATCH 23/36] sched_ext: Implement tickless support Tejun Heo
2023-11-11 2:47 ` [PATCH 24/36] sched_ext: Track tasks that are subjects of the in-flight SCX operation Tejun Heo
2023-11-11 2:47 ` [PATCH 25/36] sched_ext: Add cgroup support Tejun Heo
2023-11-11 2:47 ` [PATCH 26/36] sched_ext: Add a cgroup-based core-scheduling scheduler Tejun Heo
2023-11-11 2:47 ` [PATCH 27/36] sched_ext: Add a cgroup scheduler which uses flattened hierarchy Tejun Heo
2023-11-11 2:47 ` [PATCH 28/36] sched_ext: Implement SCX_KICK_WAIT Tejun Heo
2023-11-11 2:47 ` [PATCH 29/36] sched_ext: Implement sched_ext_ops.cpu_acquire/release() Tejun Heo
2023-11-11 2:47 ` [PATCH 30/36] sched_ext: Implement sched_ext_ops.cpu_online/offline() Tejun Heo
2023-11-11 2:47 ` [PATCH 31/36] sched_ext: Implement core-sched support Tejun Heo
2023-11-11 2:47 ` [PATCH 32/36] sched_ext: Add vtime-ordered priority queue to dispatch_q's Tejun Heo
2023-11-11 2:47 ` [PATCH 33/36] sched_ext: Documentation: scheduler: Document extensible scheduler class Tejun Heo
2023-11-11 2:48 ` [PATCH 34/36] sched_ext: Add a basic, userland vruntime scheduler Tejun Heo
2023-11-11 2:48 ` [PATCH 35/36] sched_ext: Add scx_rusty, a rust userspace hybrid scheduler Tejun Heo
2023-11-11 2:48 ` [PATCH 36/36] sched_ext: Add scx_layered, a highly configurable multi-layer scheduler Tejun Heo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20231111024835.2164816-7-tj@kernel.org \
--to=tj@kernel.org \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=brho@google.com \
--cc=bristot@redhat.com \
--cc=bsegall@google.com \
--cc=changwoo@igalia.com \
--cc=daniel@iogearbox.net \
--cc=derkling@google.com \
--cc=dietmar.eggemann@arm.com \
--cc=dschatzberg@meta.com \
--cc=dskarlat@cs.cmu.edu \
--cc=dvernet@meta.com \
--cc=haoluo@google.com \
--cc=himadrics@inria.fr \
--cc=joshdon@google.com \
--cc=juri.lelli@redhat.com \
--cc=kernel-team@meta.com \
--cc=linux-kernel@vger.kernel.org \
--cc=martin.lau@kernel.org \
--cc=memxor@gmail.com \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=pjt@google.com \
--cc=riel@surriel.com \
--cc=rostedt@goodmis.org \
--cc=torvalds@linux-foundation.org \
--cc=vincent.guittot@linaro.org \
--cc=vschneid@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).