* [PATCH 1/2] cgroup: rstat: use same convention to assign cgroup_base_stat
@ 2022-01-08 0:38 ` Wei Yang
0 siblings, 0 replies; 6+ messages in thread
From: Wei Yang @ 2022-01-08 0:38 UTC (permalink / raw)
To: tj, lizefan.x, hannes; +Cc: cgroups, linux-kernel, Wei Yang
In function cgroup_base_stat_flush(), we update cgroup_base_stat by
getting rstatc->bstat and adjust delta to related fields.
There are two convention to assign cgroup_base_stat in this function:
* rstat2 = rstat1
* rstat2.cputime = rstat1.cputime
The second convention may make audience think just field "cputime" is
updated, while cputime is the only field in cgroup_base_stat.
Let's use the same convention to eliminate this confusion.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
kernel/cgroup/rstat.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index a00875375f7d..c626d5a526c4 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -324,7 +324,7 @@ static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
/* fetch the current per-cpu values */
do {
seq = __u64_stats_fetch_begin(&rstatc->bsync);
- cur.cputime = rstatc->bstat.cputime;
+ cur = rstatc->bstat;
} while (__u64_stats_fetch_retry(&rstatc->bsync, seq));
/* propagate percpu delta to global */
--
2.33.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 1/2] cgroup: rstat: use same convention to assign cgroup_base_stat
@ 2022-01-08 0:38 ` Wei Yang
0 siblings, 0 replies; 6+ messages in thread
From: Wei Yang @ 2022-01-08 0:38 UTC (permalink / raw)
To: tj-DgEjT+Ai2ygdnm+yROfE0A, lizefan.x-EC8Uxl6Npydl57MIdRCFDg,
hannes-druUgvl0LCNAfugRpC6u6w
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA, Wei Yang
In function cgroup_base_stat_flush(), we update cgroup_base_stat by
getting rstatc->bstat and adjust delta to related fields.
There are two convention to assign cgroup_base_stat in this function:
* rstat2 = rstat1
* rstat2.cputime = rstat1.cputime
The second convention may make audience think just field "cputime" is
updated, while cputime is the only field in cgroup_base_stat.
Let's use the same convention to eliminate this confusion.
Signed-off-by: Wei Yang <richard.weiyang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
kernel/cgroup/rstat.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index a00875375f7d..c626d5a526c4 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -324,7 +324,7 @@ static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
/* fetch the current per-cpu values */
do {
seq = __u64_stats_fetch_begin(&rstatc->bsync);
- cur.cputime = rstatc->bstat.cputime;
+ cur = rstatc->bstat;
} while (__u64_stats_fetch_retry(&rstatc->bsync, seq));
/* propagate percpu delta to global */
--
2.33.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 2/2] cgroup: rstat: retrieve current bstat to delta directly
@ 2022-01-08 0:38 ` Wei Yang
0 siblings, 0 replies; 6+ messages in thread
From: Wei Yang @ 2022-01-08 0:38 UTC (permalink / raw)
To: tj, lizefan.x, hannes; +Cc: cgroups, linux-kernel, Wei Yang
Instead of retrieve current bstat to cur and copy it to delta, let's use
delta directly.
This saves one copy operation and has the same code convention as
propagating delta to parent.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
kernel/cgroup/rstat.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index c626d5a526c4..f66944c53613 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -314,7 +314,7 @@ static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
{
struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
struct cgroup *parent = cgroup_parent(cgrp);
- struct cgroup_base_stat cur, delta;
+ struct cgroup_base_stat delta;
unsigned seq;
/* Root-level stats are sourced from system-wide CPU stats */
@@ -324,11 +324,10 @@ static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
/* fetch the current per-cpu values */
do {
seq = __u64_stats_fetch_begin(&rstatc->bsync);
- cur = rstatc->bstat;
+ delta = rstatc->bstat;
} while (__u64_stats_fetch_retry(&rstatc->bsync, seq));
/* propagate percpu delta to global */
- delta = cur;
cgroup_base_stat_sub(&delta, &rstatc->last_bstat);
cgroup_base_stat_add(&cgrp->bstat, &delta);
cgroup_base_stat_add(&rstatc->last_bstat, &delta);
--
2.33.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 2/2] cgroup: rstat: retrieve current bstat to delta directly
@ 2022-01-08 0:38 ` Wei Yang
0 siblings, 0 replies; 6+ messages in thread
From: Wei Yang @ 2022-01-08 0:38 UTC (permalink / raw)
To: tj-DgEjT+Ai2ygdnm+yROfE0A, lizefan.x-EC8Uxl6Npydl57MIdRCFDg,
hannes-druUgvl0LCNAfugRpC6u6w
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA, Wei Yang
Instead of retrieve current bstat to cur and copy it to delta, let's use
delta directly.
This saves one copy operation and has the same code convention as
propagating delta to parent.
Signed-off-by: Wei Yang <richard.weiyang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
kernel/cgroup/rstat.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index c626d5a526c4..f66944c53613 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -314,7 +314,7 @@ static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
{
struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
struct cgroup *parent = cgroup_parent(cgrp);
- struct cgroup_base_stat cur, delta;
+ struct cgroup_base_stat delta;
unsigned seq;
/* Root-level stats are sourced from system-wide CPU stats */
@@ -324,11 +324,10 @@ static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
/* fetch the current per-cpu values */
do {
seq = __u64_stats_fetch_begin(&rstatc->bsync);
- cur = rstatc->bstat;
+ delta = rstatc->bstat;
} while (__u64_stats_fetch_retry(&rstatc->bsync, seq));
/* propagate percpu delta to global */
- delta = cur;
cgroup_base_stat_sub(&delta, &rstatc->last_bstat);
cgroup_base_stat_add(&cgrp->bstat, &delta);
cgroup_base_stat_add(&rstatc->last_bstat, &delta);
--
2.33.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] cgroup: rstat: use same convention to assign cgroup_base_stat
@ 2022-01-12 19:55 ` Tejun Heo
0 siblings, 0 replies; 6+ messages in thread
From: Tejun Heo @ 2022-01-12 19:55 UTC (permalink / raw)
To: Wei Yang; +Cc: lizefan.x, hannes, cgroups, linux-kernel
On Sat, Jan 08, 2022 at 12:38:16AM +0000, Wei Yang wrote:
> In function cgroup_base_stat_flush(), we update cgroup_base_stat by
> getting rstatc->bstat and adjust delta to related fields.
>
> There are two convention to assign cgroup_base_stat in this function:
>
> * rstat2 = rstat1
> * rstat2.cputime = rstat1.cputime
>
> The second convention may make audience think just field "cputime" is
> updated, while cputime is the only field in cgroup_base_stat.
>
> Let's use the same convention to eliminate this confusion.
>
> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Applied 1-2 to cgroup/for-5.18.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] cgroup: rstat: use same convention to assign cgroup_base_stat
@ 2022-01-12 19:55 ` Tejun Heo
0 siblings, 0 replies; 6+ messages in thread
From: Tejun Heo @ 2022-01-12 19:55 UTC (permalink / raw)
To: Wei Yang
Cc: lizefan.x-EC8Uxl6Npydl57MIdRCFDg, hannes-druUgvl0LCNAfugRpC6u6w,
cgroups-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA
On Sat, Jan 08, 2022 at 12:38:16AM +0000, Wei Yang wrote:
> In function cgroup_base_stat_flush(), we update cgroup_base_stat by
> getting rstatc->bstat and adjust delta to related fields.
>
> There are two convention to assign cgroup_base_stat in this function:
>
> * rstat2 = rstat1
> * rstat2.cputime = rstat1.cputime
>
> The second convention may make audience think just field "cputime" is
> updated, while cputime is the only field in cgroup_base_stat.
>
> Let's use the same convention to eliminate this confusion.
>
> Signed-off-by: Wei Yang <richard.weiyang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Applied 1-2 to cgroup/for-5.18.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-01-12 19:57 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2022-01-08 0:38 ` [PATCH 2/2] cgroup: rstat: retrieve current bstat to delta directly Wei Yang
2022-01-08 0:38 ` Wei Yang
2022-01-12 19:55 ` [PATCH 1/2] cgroup: rstat: use same convention to assign cgroup_base_stat Tejun Heo
2022-01-12 19:55 ` Tejun Heo
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