From f5e8b140cd1324cf2c9c17487b8f444098624797 Mon Sep 17 00:00:00 2001 From: Ryan Roberts Date: Mon, 9 Jun 2025 10:27:25 +0100 Subject: [PATCH] mm/readahead: make space in struct file_ra_state We need to be able to store the preferred folio order associated with a readahead request in the struct file_ra_state so that we can more accurately increase the order across subsequent readahead requests. But struct file_ra_state is per-struct file, so we don't really want to increase it's size. mmap_miss is currently 32 bits but it is only counted up to 10 * MMAP_LOTSAMISS, which is currently defined as 1000. So 16 bits should be plenty. Redefine it to unsigned short, making room for order as unsigned short in follow up commit. Link: https://lkml.kernel.org/r/20250609092729.274960-4-ryan.roberts@arm.com Signed-off-by: Ryan Roberts Acked-by: David Hildenbrand Reviewed-by: Jan Kara Cc: Chaitanya S Prakash Cc: Will Deacon Signed-off-by: Andrew Morton --- include/linux/fs.h | 2 +- mm/filemap.c | 11 ++++++----- 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 62634af97da65..ef819b232d66f 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1054,7 +1054,7 @@ struct file_ra_state { unsigned int size; unsigned int async_size; unsigned int ra_pages; - unsigned int mmap_miss; + unsigned short mmap_miss; loff_t prev_pos; }; diff --git a/mm/filemap.c b/mm/filemap.c index a6459874bb2aa..7bb4ffca84875 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3217,7 +3217,7 @@ static struct file *do_sync_mmap_readahead(struct vm_fault *vmf) DEFINE_READAHEAD(ractl, file, ra, mapping, vmf->pgoff); struct file *fpin = NULL; unsigned long vm_flags = vmf->vma->vm_flags; - unsigned int mmap_miss; + unsigned short mmap_miss; #ifdef CONFIG_TRANSPARENT_HUGEPAGE /* Use the readahead code, even if readahead is disabled */ @@ -3285,7 +3285,7 @@ static struct file *do_async_mmap_readahead(struct vm_fault *vmf, struct file_ra_state *ra = &file->f_ra; DEFINE_READAHEAD(ractl, file, ra, file->f_mapping, vmf->pgoff); struct file *fpin = NULL; - unsigned int mmap_miss; + unsigned short mmap_miss; /* If we don't want any read-ahead, don't bother */ if (vmf->vma->vm_flags & VM_RAND_READ || !ra->ra_pages) @@ -3605,7 +3605,7 @@ skip: static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf, struct folio *folio, unsigned long start, unsigned long addr, unsigned int nr_pages, - unsigned long *rss, unsigned int *mmap_miss) + unsigned long *rss, unsigned short *mmap_miss) { vm_fault_t ret = 0; struct page *page = folio_page(folio, start); @@ -3667,7 +3667,7 @@ skip: static vm_fault_t filemap_map_order0_folio(struct vm_fault *vmf, struct folio *folio, unsigned long addr, - unsigned long *rss, unsigned int *mmap_miss) + unsigned long *rss, unsigned short *mmap_miss) { vm_fault_t ret = 0; struct page *page = &folio->page; @@ -3709,7 +3709,8 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf, struct folio *folio; vm_fault_t ret = 0; unsigned long rss = 0; - unsigned int nr_pages = 0, mmap_miss = 0, mmap_miss_saved, folio_type; + unsigned int nr_pages = 0, folio_type; + unsigned short mmap_miss = 0, mmap_miss_saved; rcu_read_lock(); folio = next_uptodate_folio(&xas, mapping, end_pgoff); -- 2.47.2