| Message ID | 20200419013921.14390-4-richard.weiyang@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/4] mm/swapfile.c: found_free could be represented by (tmp < max) | expand |
Wei Yang <richard.weiyang@gmail.com> writes: > Each time it needs jump to new_cluster, it is sure current > percpu_cluster is null. > > Move the new_cluster to check free_clusters directly. > > Signed-off-by: Wei Yang <richard.weiyang@gmail.com> > --- > mm/swapfile.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/swapfile.c b/mm/swapfile.c > index 07b0bc095411..78e92ff14c79 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -603,9 +603,9 @@ static bool scan_swap_map_try_ssd_cluster(struct swap_info_struct *si, > struct swap_cluster_info *ci; > unsigned long tmp, max; > > -new_cluster: > cluster = this_cpu_ptr(si->percpu_cluster); > if (cluster_is_null(&cluster->index)) { > +new_cluster: > if (!cluster_list_empty(&si->free_clusters)) { > cluster->index = si->free_clusters.head; > cluster->next = cluster_next(&cluster->index) * In swap_do_scheduled_discard(), we will unlock si->lock, so the percpu_cluster may be changed after we releasing the lock. Or the current thread may be moved to a different CPU. Best Regards, Huang, Ying
On Mon, Apr 20, 2020 at 09:41:43AM +0800, Huang, Ying wrote: >Wei Yang <richard.weiyang@gmail.com> writes: > >> Each time it needs jump to new_cluster, it is sure current >> percpu_cluster is null. >> >> Move the new_cluster to check free_clusters directly. >> >> Signed-off-by: Wei Yang <richard.weiyang@gmail.com> >> --- >> mm/swapfile.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/mm/swapfile.c b/mm/swapfile.c >> index 07b0bc095411..78e92ff14c79 100644 >> --- a/mm/swapfile.c >> +++ b/mm/swapfile.c >> @@ -603,9 +603,9 @@ static bool scan_swap_map_try_ssd_cluster(struct swap_info_struct *si, >> struct swap_cluster_info *ci; >> unsigned long tmp, max; >> >> -new_cluster: >> cluster = this_cpu_ptr(si->percpu_cluster); >> if (cluster_is_null(&cluster->index)) { >> +new_cluster: >> if (!cluster_list_empty(&si->free_clusters)) { >> cluster->index = si->free_clusters.head; >> cluster->next = cluster_next(&cluster->index) * > >In swap_do_scheduled_discard(), we will unlock si->lock, so the >percpu_cluster may be changed after we releasing the lock. Or the >current thread may be moved to a different CPU. Thanks, you are right. > >Best Regards, >Huang, Ying
diff --git a/mm/swapfile.c b/mm/swapfile.c index 07b0bc095411..78e92ff14c79 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -603,9 +603,9 @@ static bool scan_swap_map_try_ssd_cluster(struct swap_info_struct *si, struct swap_cluster_info *ci; unsigned long tmp, max; -new_cluster: cluster = this_cpu_ptr(si->percpu_cluster); if (cluster_is_null(&cluster->index)) { +new_cluster: if (!cluster_list_empty(&si->free_clusters)) { cluster->index = si->free_clusters.head; cluster->next = cluster_next(&cluster->index) *
Each time it needs jump to new_cluster, it is sure current percpu_cluster is null. Move the new_cluster to check free_clusters directly. Signed-off-by: Wei Yang <richard.weiyang@gmail.com> --- mm/swapfile.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)