On 2/19/20 1:00 PM, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
>
> The readahead code is part of the page cache so should be found in the
> pagemap.h file. force_page_cache_readahead is only used within mm,
> so move it to mm/internal.h instead. Remove the parameter names where
> they add no value, and rename the ones which were actively misleading.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> block/blk-core.c | 1 +
> include/linux/mm.h | 19 -------------------
> include/linux/pagemap.h | 8 ++++++++
> mm/fadvise.c | 2 ++
> mm/internal.h | 2 ++
> 5 files changed, 13 insertions(+), 19 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 089e890ab208..41417bb93634 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -20,6 +20,7 @@
> #include <linux/blk-mq.h>
> #include <linux/highmem.h>
> #include <linux/mm.h>
> +#include <linux/pagemap.h>
Yes. But I think these files also need a similar change:
fs/btrfs/disk-io.c
fs/nfs/super.c
...because they also use VM_READAHEAD_PAGES, and do not directly include
pagemap.h yet.
> #include <linux/kernel_stat.h>
> #include <linux/string.h>
> #include <linux/init.h>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 52269e56c514..68dcda9a2112 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2401,25 +2401,6 @@ extern vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf);
> int __must_check write_one_page(struct page *page);
> void task_dirty_inc(struct task_struct *tsk);
>
> -/* readahead.c */
> -#define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE)
> -
> -int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
> - pgoff_t offset, unsigned long nr_to_read);
> -
> -void page_cache_sync_readahead(struct address_space *mapping,
> - struct file_ra_state *ra,
> - struct file *filp,
> - pgoff_t offset,
> - unsigned long size);
> -
> -void page_cache_async_readahead(struct address_space *mapping,
> - struct file_ra_state *ra,
> - struct file *filp,
> - struct page *pg,
> - pgoff_t offset,
> - unsigned long size);
> -
> extern unsigned long stack_guard_gap;
> /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
> extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index ccb14b6a16b5..24894b9b90c9 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -614,6 +614,14 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask);
> void delete_from_page_cache_batch(struct address_space *mapping,
> struct pagevec *pvec);
>
> +#define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE)
> +
> +void page_cache_sync_readahead(struct address_space *, struct file_ra_state *,
> + struct file *, pgoff_t index, unsigned long req_count);
Yes, "struct address_space *mapping" is weird, but I don't know if it's
"misleading", given that it's actually one of the things you have to learn
right from the beginning, with linux-mm, right? Or is that about to change?
I'm not asking to restore this to "struct address_space *mapping", but I thought
it's worth mentioning out loud, especially if you or others are planning on
changing those names or something. Just curious.
thanks,
--
John Hubbard
NVIDIA
> +void page_cache_async_readahead(struct address_space *, struct file_ra_state *,
> + struct file *, struct page *, pgoff_t index,
> + unsigned long req_count);
> +
> /*
> * Like add_to_page_cache_locked, but used to add newly allocated pages:
> * the page is new, so we can just run __SetPageLocked() against it.
> diff --git a/mm/fadvise.c b/mm/fadvise.c
> index 4f17c83db575..3efebfb9952c 100644
> --- a/mm/fadvise.c
> +++ b/mm/fadvise.c
> @@ -22,6 +22,8 @@
>
> #include <asm/unistd.h>
>
> +#include "internal.h"
> +
> /*
> * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
> * deactivate the pages and clear PG_Referenced.
> diff --git a/mm/internal.h b/mm/internal.h
> index 3cf20ab3ca01..83f353e74654 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -49,6 +49,8 @@ void unmap_page_range(struct mmu_gather *tlb,
> unsigned long addr, unsigned long end,
> struct zap_details *details);
>
> +int force_page_cache_readahead(struct address_space *, struct file *,
> + pgoff_t index, unsigned long nr_to_read);
> extern unsigned int __do_page_cache_readahead(struct address_space *mapping,
> struct file *filp, pgoff_t offset, unsigned long nr_to_read,
> unsigned long lookahead_size);
>
