diff mbox series

[v7,01/24] mm: Move readahead prototypes from mm.h

Message ID 20200219210103.32400-2-willy@infradead.org
State New, archived
Headers show
Series Change readahead API | expand

Commit Message

Matthew Wilcox Feb. 19, 2020, 9 p.m. UTC
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

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@infradead.org>
---
 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(-)

Comments

John Hubbard Feb. 21, 2020, 2:43 a.m. UTC | #1
On 2/19/20 1:00 PM, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> 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@infradead.org>
> ---
>  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,
Matthew Wilcox Feb. 21, 2020, 9:48 p.m. UTC | #2
On Thu, Feb 20, 2020 at 06:43:31PM -0800, John Hubbard wrote:
> Yes. But I think these files also need a similar change:
> 
>     fs/btrfs/disk-io.c

That gets pagemap.h through ctree.h, so I think it's fine.  It's
already using mapping_set_gfp_mask(), so it already depends on pagemap.h.

>     fs/nfs/super.c

That gets it through linux/nfs_fs.h.

I was reluctant to not add it to blk-core.c because it doesn't seem
necessarily intuitive that the block device core would include pagemap.h.

That said, blkdev.h does include pagemap.h, so maybe I don't need to
include it here.

> ...because they also use VM_READAHEAD_PAGES, and do not directly include
> pagemap.h yet.

> > +#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.

No plans (on my part) to change the name, although I have heard people
grumbling that there's very little need for it to be a separate struct
from inode, except for the benefit of coda, which is not exactly a
filesystem with a lot of users ...

Anyway, no plans to change it.  If there were something _special_ about
it like a theoretical:

void mapping_dedup(struct address_space *canonical,
		struct address_space *victim);

then that's useful information and shouldn't be deleted.  But I don't
think the word 'mapping' there conveys anything useful (other than the
convention is to call a 'struct address_space' a mapping, which you'll
see soon enough once you look at any of the .c files).
John Hubbard Feb. 22, 2020, 12:15 a.m. UTC | #3
On 2/21/20 1:48 PM, Matthew Wilcox wrote:
> On Thu, Feb 20, 2020 at 06:43:31PM -0800, John Hubbard wrote:
>> Yes. But I think these files also need a similar change:
>>
>>     fs/btrfs/disk-io.c
> 
> That gets pagemap.h through ctree.h, so I think it's fine.  It's
> already using mapping_set_gfp_mask(), so it already depends on pagemap.h.
> 
>>     fs/nfs/super.c
> 
> That gets it through linux/nfs_fs.h.
> 
> I was reluctant to not add it to blk-core.c because it doesn't seem
> necessarily intuitive that the block device core would include pagemap.h.
> 
> That said, blkdev.h does include pagemap.h, so maybe I don't need to
> include it here.

OK. Looks good (either through blkdev.h or as-is), so:

    Reviewed-by: John Hubbard <jhubbard@nvidia.com>


> 
>> ...because they also use VM_READAHEAD_PAGES, and do not directly include
>> pagemap.h yet.
> 
>>> +#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.
> 
> No plans (on my part) to change the name, although I have heard people
> grumbling that there's very little need for it to be a separate struct
> from inode, except for the benefit of coda, which is not exactly a
> filesystem with a lot of users ...
> 
> Anyway, no plans to change it.  If there were something _special_ about
> it like a theoretical:
> 
> void mapping_dedup(struct address_space *canonical,
> 		struct address_space *victim);
> 
> then that's useful information and shouldn't be deleted.  But I don't
> think the word 'mapping' there conveys anything useful (other than the
> convention is to call a 'struct address_space' a mapping, which you'll
> see soon enough once you look at any of the .c files).
> 

OK, that's consistent and makes sense.


thanks,
Christoph Hellwig Feb. 24, 2020, 9:32 p.m. UTC | #4
On Wed, Feb 19, 2020 at 01:00:40PM -0800, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> 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.

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

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>
 #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);
+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);