From: Kairui Song It doesn't have to check the device flag, as the allocator will also check the device flag and refuse to allocate if the device is not writable. This might cause a trivial waste of CPU cycles of hibernate allocation raced with swapoff, but that is very unlikely to happen. Removing the check on the common path should be more helpful. Signed-off-by: Kairui Song --- mm/swapfile.c | 38 ++++++++++++++++++-------------------- 1 file changed, 18 insertions(+), 20 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index 32e0e7545ab8..0d1b17c99221 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1936,27 +1936,25 @@ swp_entry_t swap_alloc_hibernation_slot(int type) /* This is called for allocating swap entry, not cache */ if (get_swap_device_info(si)) { - if (si->flags & SWP_WRITEOK) { - /* - * Try the local cluster first if it matches the device. If - * not, try grab a new cluster and override local cluster. - */ - local_lock(&percpu_swap_cluster.lock); - pcp_si = this_cpu_read(percpu_swap_cluster.si[0]); - pcp_offset = this_cpu_read(percpu_swap_cluster.offset[0]); - if (pcp_si == si && pcp_offset) { - ci = swap_cluster_lock(si, pcp_offset); - if (cluster_is_usable(ci, 0)) - offset = alloc_swap_scan_cluster(si, ci, NULL, pcp_offset); - else - swap_cluster_unlock(ci); - } - if (!offset) - offset = cluster_alloc_swap_entry(si, NULL); - local_unlock(&percpu_swap_cluster.lock); - if (offset) - entry = swp_entry(si->type, offset); + /* + * Try the local cluster first if it matches the device. If + * not, try grab a new cluster and override local cluster. + */ + local_lock(&percpu_swap_cluster.lock); + pcp_si = this_cpu_read(percpu_swap_cluster.si[0]); + pcp_offset = this_cpu_read(percpu_swap_cluster.offset[0]); + if (pcp_si == si && pcp_offset) { + ci = swap_cluster_lock(si, pcp_offset); + if (cluster_is_usable(ci, 0)) + offset = alloc_swap_scan_cluster(si, ci, NULL, pcp_offset); + else + swap_cluster_unlock(ci); } + if (!offset) + offset = cluster_alloc_swap_entry(si, NULL); + local_unlock(&percpu_swap_cluster.lock); + if (offset) + entry = swp_entry(si->type, offset); put_swap_device(si); } fail: -- 2.52.0