mm/memcontrol: hoist pstatc_pcpu assignment out of CPU loop

In mem_cgroup_alloc(), the assignment of pstatc_pcpu is invariant with
respect to the for_each_possible_cpu() loop: both the 'parent' pointer and
'parent->vmstats_percpu' remain constant throughout all iterations.

The original code redundantly re-evaluated the 'if (parent)' condition and
reassigned pstatc_pcpu on every CPU iteration, then repeated the same
ternary check 'parent ?  pstatc_pcpu : NULL' when storing into
statc->parent_pcpu.

Move the single conditional assignment of pstatc_pcpu to before the loop,
resolving both the loop-invariant placement issue and the duplicated null
check.  On systems with a large number of possible CPUs, this eliminates
repeated branch evaluation with no functional change.

No functional change intended.

Link: https://lore.kernel.org/20260429084216.186238-1-hui.zhu@linux.dev
Signed-off-by: Hui Zhu <zhuhui@kylinos.cn>
Reviewed-by: SeongJae Park <sj@kernel.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

0 files changed, 0 insertions, 0 deletions