Move shmem_recalc_inode() out of the loop in memfd_luo_retrieve_folios() to improve performance when restoring large memfds. Currently, shmem_recalc_inode() is called for each folio during restore, which is O(n) expensive operations. This patch collects the number of successfully added folios and calls shmem_recalc_inode() once after the loop completes, reducing complexity to O(1). Additionally, fix the error path to also call shmem_recalc_inode() for the folios that were successfully added before the error occurred. Reviewed-by: Pasha Tatashin Signed-off-by: Chenghao Duan --- mm/memfd_luo.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/memfd_luo.c b/mm/memfd_luo.c index 953440994ad2..2a01eaff03c2 100644 --- a/mm/memfd_luo.c +++ b/mm/memfd_luo.c @@ -395,7 +395,7 @@ static int memfd_luo_retrieve_folios(struct file *file, struct inode *inode = file_inode(file); struct address_space *mapping = inode->i_mapping; struct folio *folio; - long npages; + long npages, nr_added_pages = 0; int err = -EIO; long i; @@ -450,12 +450,14 @@ static int memfd_luo_retrieve_folios(struct file *file, goto unlock_folio; } - shmem_recalc_inode(inode, npages, 0); + nr_added_pages += npages; folio_add_lru(folio); folio_unlock(folio); folio_put(folio); } + shmem_recalc_inode(inode, nr_added_pages, 0); + return 0; unlock_folio: @@ -474,6 +476,8 @@ static int memfd_luo_retrieve_folios(struct file *file, folio_put(folio); } + shmem_recalc_inode(inode, nr_added_pages, 0); + return err; } -- 2.25.1