| Message ID | 20200119030636.11899-7-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 19-01-20 11:06:34, Wei Yang wrote: > When page is not queued for migration, there are two possible cases: > > * page already on the target node > * failed to add to migration queue > > Current code handle them differently, this leads to a behavior > inconsistency. > > Usually for each page's status, we just do store for once. While for the > page already on the target node, we might store the node information for > twice: > > * once when we found the page is on the target node > * second when moving the pages to target node successfully after above > action > > The reason is even we don't add the page to pagelist, but store_status() > does store in a range which still contains the page. > > This patch handles these two cases in the same way to reduce this > inconsistency and also make the code a little easier to read. Yeah, the improvement is really marginal. I do not feel strongly one way or another. > Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> > --- > mm/migrate.c | 16 ++++++++-------- > 1 file changed, 8 insertions(+), 8 deletions(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index 46a5697b7fc6..aee5aeb082c4 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1657,18 +1657,18 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, > err = add_page_for_migration(mm, addr, current_node, > &pagelist, flags & MPOL_MF_MOVE_ALL); > > - if (!err) { > - /* The page is already on the target node */ > - err = store_status(status, i, current_node, 1); > - if (err) > - goto out_flush; > - continue; > - } else if (err > 0) { > + if (err > 0) { > /* The page is successfully queued for migration */ > continue; > } > > - err = store_status(status, i, err, 1); > + /* > + * Two possible cases for err here: > + * == 0: page is already on the target node, then store > + * current_node to status > + * < 0: failed to add page to list, then store err to status > + */ > + err = store_status(status, i, err ? : current_node, 1); > if (err) > goto out_flush; > > -- > 2.17.1 >
diff --git a/mm/migrate.c b/mm/migrate.c index 46a5697b7fc6..aee5aeb082c4 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1657,18 +1657,18 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, err = add_page_for_migration(mm, addr, current_node, &pagelist, flags & MPOL_MF_MOVE_ALL); - if (!err) { - /* The page is already on the target node */ - err = store_status(status, i, current_node, 1); - if (err) - goto out_flush; - continue; - } else if (err > 0) { + if (err > 0) { /* The page is successfully queued for migration */ continue; } - err = store_status(status, i, err, 1); + /* + * Two possible cases for err here: + * == 0: page is already on the target node, then store + * current_node to status + * < 0: failed to add page to list, then store err to status + */ + err = store_status(status, i, err ? : current_node, 1); if (err) goto out_flush;
When page is not queued for migration, there are two possible cases: * page already on the target node * failed to add to migration queue Current code handle them differently, this leads to a behavior inconsistency. Usually for each page's status, we just do store for once. While for the page already on the target node, we might store the node information for twice: * once when we found the page is on the target node * second when moving the pages to target node successfully after above action The reason is even we don't add the page to pagelist, but store_status() does store in a range which still contains the page. This patch handles these two cases in the same way to reduce this inconsistency and also make the code a little easier to read. Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> --- mm/migrate.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)