| Message ID | 20200119030636.11899-3-richardw.yang@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm/migrate.c: cleanup on do_pages_move() | expand |
On Sun, 19 Jan 2020, Wei Yang wrote: > diff --git a/mm/migrate.c b/mm/migrate.c > index ba7cf4fa43a0..c3ef70de5876 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1664,11 +1664,9 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, > err = do_move_pages_to_node(mm, &pagelist, current_node); > if (err) > goto out; > - if (i > start) { > - err = store_status(status, start, current_node, i - start); > - if (err) > - goto out; > - } > + err = store_status(status, start, current_node, i - start); > + if (err) > + goto out; > current_node = NUMA_NO_NODE; > } > out_flush: Not sure this is useful, it relies on the implementation of store_status() when i == start and the overhead of the function call should actually be slower than the simple conditional to avoid it in that case?
On Sun, Jan 19, 2020 at 02:14:28PM -0800, David Rientjes wrote: >On Sun, 19 Jan 2020, Wei Yang wrote: > >> diff --git a/mm/migrate.c b/mm/migrate.c >> index ba7cf4fa43a0..c3ef70de5876 100644 >> --- a/mm/migrate.c >> +++ b/mm/migrate.c >> @@ -1664,11 +1664,9 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, >> err = do_move_pages_to_node(mm, &pagelist, current_node); >> if (err) >> goto out; >> - if (i > start) { >> - err = store_status(status, start, current_node, i - start); >> - if (err) >> - goto out; >> - } >> + err = store_status(status, start, current_node, i - start); >> + if (err) >> + goto out; >> current_node = NUMA_NO_NODE; >> } >> out_flush: > >Not sure this is useful, it relies on the implementation of store_status() >when i == start and the overhead of the function call should actually be >slower than the simple conditional to avoid it in that case? Not sure about this. While this patch is a transient state for the following cleanup. The purpose of this is to make the consolidation a little easy to review.
On Sun 19-01-20 11:06:30, Wei Yang wrote: > Till here, i must no less than start. And if i equals to start, > store_status() would always return 0. > > Remove some unnecessary check to make it easy to read and prepare for > further cleanup. You are right. This is likely a left over from the development. i >= start because the former is the actual iterator and start is the first index with the cached node. Dropping the check improves readability because one might indeed wonder why this is the only place to do the check and the overal iteration is complex enough to add more questions on top. > Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Thanks! > --- > mm/migrate.c | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index ba7cf4fa43a0..c3ef70de5876 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1664,11 +1664,9 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, > err = do_move_pages_to_node(mm, &pagelist, current_node); > if (err) > goto out; > - if (i > start) { > - err = store_status(status, start, current_node, i - start); > - if (err) > - goto out; > - } > + err = store_status(status, start, current_node, i - start); > + if (err) > + goto out; > current_node = NUMA_NO_NODE; > } > out_flush: > -- > 2.17.1
diff --git a/mm/migrate.c b/mm/migrate.c index ba7cf4fa43a0..c3ef70de5876 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1664,11 +1664,9 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, err = do_move_pages_to_node(mm, &pagelist, current_node); if (err) goto out; - if (i > start) { - err = store_status(status, start, current_node, i - start); - if (err) - goto out; - } + err = store_status(status, start, current_node, i - start); + if (err) + goto out; current_node = NUMA_NO_NODE; } out_flush:
Till here, i must no less than start. And if i equals to start, store_status() would always return 0. Remove some unnecessary check to make it easy to read and prepare for further cleanup. Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> --- mm/migrate.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)