From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: mm/readahead: make do_page_cache_ra take a readahead_control Rename __do_page_cache_readahead() to do_page_cache_ra() and call it directly from ondemand_readahead() instead of indirecting via ra_submit(). Link: https://lkml.kernel.org/r/20200903140844.14194-5-willy@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Cc: Eric Biggers <ebiggers@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/internal.h | 11 +++++------ mm/readahead.c | 28 +++++++++++++++------------- 2 files changed, 20 insertions(+), 19 deletions(-) --- a/mm/internal.h~mm-readahead-make-do_page_cache_ra-take-a-readahead_control +++ a/mm/internal.h @@ -51,18 +51,17 @@ void unmap_page_range(struct mmu_gather void force_page_cache_readahead(struct address_space *, struct file *, pgoff_t index, unsigned long nr_to_read); -void __do_page_cache_readahead(struct address_space *, struct file *, - pgoff_t index, unsigned long nr_to_read, - unsigned long lookahead_size); +void do_page_cache_ra(struct readahead_control *, + unsigned long nr_to_read, unsigned long lookahead_size); /* * Submit IO for the read-ahead request in file_ra_state. */ static inline void ra_submit(struct file_ra_state *ra, - struct address_space *mapping, struct file *filp) + struct address_space *mapping, struct file *file) { - __do_page_cache_readahead(mapping, filp, - ra->start, ra->size, ra->async_size); + DEFINE_READAHEAD(ractl, file, mapping, ra->start); + do_page_cache_ra(&ractl, ra->size, ra->async_size); } struct page *find_get_entry(struct address_space *mapping, pgoff_t index); --- a/mm/readahead.c~mm-readahead-make-do_page_cache_ra-take-a-readahead_control +++ a/mm/readahead.c @@ -241,17 +241,16 @@ void page_cache_ra_unbounded(struct read EXPORT_SYMBOL_GPL(page_cache_ra_unbounded); /* - * __do_page_cache_readahead() actually reads a chunk of disk. It allocates + * do_page_cache_ra() actually reads a chunk of disk. It allocates * the pages first, then submits them for I/O. This avoids the very bad * behaviour which would occur if page allocations are causing VM writeback. * We really don't want to intermingle reads and writes like that. */ -void __do_page_cache_readahead(struct address_space *mapping, - struct file *file, pgoff_t index, unsigned long nr_to_read, - unsigned long lookahead_size) +void do_page_cache_ra(struct readahead_control *ractl, + unsigned long nr_to_read, unsigned long lookahead_size) { - DEFINE_READAHEAD(ractl, file, mapping, index); - struct inode *inode = mapping->host; + struct inode *inode = ractl->mapping->host; + unsigned long index = readahead_index(ractl); loff_t isize = i_size_read(inode); pgoff_t end_index; /* The last page we want to read */ @@ -265,7 +264,7 @@ void __do_page_cache_readahead(struct ad if (nr_to_read > end_index - index) nr_to_read = end_index - index + 1; - page_cache_ra_unbounded(&ractl, nr_to_read, lookahead_size); + page_cache_ra_unbounded(ractl, nr_to_read, lookahead_size); } /* @@ -273,10 +272,11 @@ void __do_page_cache_readahead(struct ad * memory at once. */ void force_page_cache_readahead(struct address_space *mapping, - struct file *filp, pgoff_t index, unsigned long nr_to_read) + struct file *file, pgoff_t index, unsigned long nr_to_read) { + DEFINE_READAHEAD(ractl, file, mapping, index); struct backing_dev_info *bdi = inode_to_bdi(mapping->host); - struct file_ra_state *ra = &filp->f_ra; + struct file_ra_state *ra = &file->f_ra; unsigned long max_pages; if (unlikely(!mapping->a_ops->readpage && !mapping->a_ops->readpages && @@ -294,7 +294,7 @@ void force_page_cache_readahead(struct a if (this_chunk > nr_to_read) this_chunk = nr_to_read; - __do_page_cache_readahead(mapping, filp, index, this_chunk, 0); + do_page_cache_ra(&ractl, this_chunk, 0); index += this_chunk; nr_to_read -= this_chunk; @@ -432,10 +432,11 @@ static int try_context_readahead(struct * A minimal readahead algorithm for trivial sequential/random reads. */ static void ondemand_readahead(struct address_space *mapping, - struct file_ra_state *ra, struct file *filp, + struct file_ra_state *ra, struct file *file, bool hit_readahead_marker, pgoff_t index, unsigned long req_size) { + DEFINE_READAHEAD(ractl, file, mapping, index); struct backing_dev_info *bdi = inode_to_bdi(mapping->host); unsigned long max_pages = ra->ra_pages; unsigned long add_pages; @@ -516,7 +517,7 @@ static void ondemand_readahead(struct ad * standalone, small random read * Read as is, and do not pollute the readahead state. */ - __do_page_cache_readahead(mapping, filp, index, req_size, 0); + do_page_cache_ra(&ractl, req_size, 0); return; initial_readahead: @@ -542,7 +543,8 @@ readit: } } - ra_submit(ra, mapping, filp); + ractl._index = ra->start; + do_page_cache_ra(&ractl, ra->size, ra->async_size); } /** _
