From: Kaitao Cheng <pilgrimtao@xxxxxxxxx> Subject: mm/memcontrol.c: cleanup some useless code Compound pages handling in mem_cgroup_migrate is more convoluted than necessary. The state is duplicated in compound variable and the same could be achieved by PageTransHuge check which is trivial and hpage_nr_pages is already PageTransHuge aware. It is much simpler to just use hpage_nr_pages for nr_pages and replace the local variable by PageTransHuge check directly Link: http://lkml.kernel.org/r/20191210160450.3395-1-pilgrimtao@xxxxxxxxx Signed-off-by: Kaitao Cheng <pilgrimtao@xxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memcontrol.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/mm/memcontrol.c~mm-cleanup-some-useless-code +++ a/mm/memcontrol.c @@ -6633,7 +6633,6 @@ void mem_cgroup_migrate(struct page *old { struct mem_cgroup *memcg; unsigned int nr_pages; - bool compound; unsigned long flags; VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage); @@ -6655,8 +6654,7 @@ void mem_cgroup_migrate(struct page *old return; /* Force-charge the new page. The old one will be freed soon */ - compound = PageTransHuge(newpage); - nr_pages = compound ? hpage_nr_pages(newpage) : 1; + nr_pages = hpage_nr_pages(newpage); page_counter_charge(&memcg->memory, nr_pages); if (do_memsw_account()) @@ -6666,7 +6664,8 @@ void mem_cgroup_migrate(struct page *old commit_charge(newpage, memcg, false); local_irq_save(flags); - mem_cgroup_charge_statistics(memcg, newpage, compound, nr_pages); + mem_cgroup_charge_statistics(memcg, newpage, PageTransHuge(newpage), + nr_pages); memcg_check_events(memcg, newpage); local_irq_restore(flags); } _
