Commit f5e8b140 authored by Ryan Roberts's avatar Ryan Roberts Committed by Andrew Morton
Browse files

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: default avatarRyan Roberts <ryan.roberts@arm.com>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Cc: Chaitanya S Prakash <chaitanyas.prakash@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 18ebe55a

include/linux/fs.h

+1 −1
Original line number Diff line number Diff line
@@ -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;

};

mm/filemap.c

+6 −5
Original line number Diff line number Diff line
@@ -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 @@ static struct folio *next_uptodate_folio(struct xa_state *xas, 
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 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf, 


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);