From: Kairui Song Date: Wed, 6 Aug 2025 16:17:47 +0000 (+0800) Subject: mm, swap: remove fragment clusters counter X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=4ecbcbb0940de01b938ca8aba8b9c398118763f9;p=users%2Fjedix%2Flinux-maple.git mm, swap: remove fragment clusters counter It was used for calculating the iteration number when the swap allocator wants to scan the whole fragment list. Now the allocator only scans one fragment cluster at a time, so no one uses this counter anymore. Remove it as a cleanup; the performance change is marginal: Build linux kernel using 10G ZRAM, make -j96, defconfig with 2G cgroup memory limit, on top of tmpfs, 64kB mTHP enabled: Before: sys time: 6278.45s After: sys time: 6176.34s Change to 8G ZRAM: Before: sys time: 5572.85s After: sys time: 5531.49s Link: https://lkml.kernel.org/r/20250806161748.76651-3-ryncsn@gmail.com Signed-off-by: Kairui Song Reviewed-by: Nhat Pham Acked-by: Chris Li Cc: Baoquan He Cc: Barry Song Cc: "Huang, Ying" Cc: Kemeng Shi Signed-off-by: Andrew Morton --- diff --git a/include/linux/swap.h b/include/linux/swap.h index 7012a0f758d8..f32f76ceb243 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -310,7 +310,6 @@ struct swap_info_struct { /* list of cluster that contains at least one free slot */ struct list_head frag_clusters[SWAP_NR_ORDERS]; /* list of cluster that are fragmented or contented */ - atomic_long_t frag_cluster_nr[SWAP_NR_ORDERS]; unsigned int pages; /* total of usable pages of swap */ atomic_long_t inuse_pages; /* number of those currently in use */ struct swap_sequential_cluster *global_cluster; /* Use one global cluster for rotating device */ diff --git a/mm/swapfile.c b/mm/swapfile.c index 1f1110e37f68..5fdb3cb2b8b7 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -470,11 +470,6 @@ static void move_cluster(struct swap_info_struct *si, else list_move_tail(&ci->list, list); spin_unlock(&si->lock); - - if (ci->flags == CLUSTER_FLAG_FRAG) - atomic_long_dec(&si->frag_cluster_nr[ci->order]); - else if (new_flags == CLUSTER_FLAG_FRAG) - atomic_long_inc(&si->frag_cluster_nr[ci->order]); ci->flags = new_flags; } @@ -965,7 +960,6 @@ new_cluster: * allocation, but reclaim may drop si->lock and race with another user. */ while ((ci = isolate_lock_cluster(si, &si->frag_clusters[o]))) { - atomic_long_dec(&si->frag_cluster_nr[o]); found = alloc_swap_scan_cluster(si, ci, cluster_offset(si, ci), 0, usage); if (found) @@ -3217,7 +3211,6 @@ static struct swap_cluster_info *setup_clusters(struct swap_info_struct *si, for (i = 0; i < SWAP_NR_ORDERS; i++) { INIT_LIST_HEAD(&si->nonfull_clusters[i]); INIT_LIST_HEAD(&si->frag_clusters[i]); - atomic_long_set(&si->frag_cluster_nr[i], 0); } /*