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* [PATCH -next v2] include/linux/mm.h: move nr_free_buffer_pages from swap.h to mm.h
@ 2021-08-15 11:50 Mianhan Liu
  2021-08-15 15:30 ` Matthew Wilcox
  0 siblings, 1 reply; 2+ messages in thread
From: Mianhan Liu @ 2021-08-15 11:50 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-mm, linux-kernel, Eric Dumazet, Mianhan Liu

nr_free_buffer_pages could be exposed through mm.h instead of swap.h.
The advantage of this change is that it can reduce the obsolete includes.
For example, net/ipv4/tcp.c wouldn't need swap.h any more since it has
already included mm.h.
Moreover, after preprocessing all the files that use nr_free_buffer_pages,
it turns out that those files have already included mm.h.
Thus, we can move nr_free_buffer_pages from swap.h to mm.h safely. This change
will not affect the compilation of other files.

Signed-off-by: Mianhan Liu <liumh1@shanghaitech.edu.cn>
---
 include/linux/mm.h   | 1 +
 include/linux/swap.h | 2 +-
 net/ipv4/tcp.c       | 1 -
 3 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index ce8fc0fd6..6ca7b7fba 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -871,6 +871,7 @@ void put_pages_list(struct list_head *pages);
 void split_page(struct page *page, unsigned int order);
 void folio_copy(struct folio *dst, struct folio *src);
 
+extern unsigned long nr_free_buffer_pages(void);
 /*
  * Compound pages have a destructor function.  Provide a
  * prototype for that function and accessor functions.
diff --git a/include/linux/swap.h b/include/linux/swap.h
index cdf0957a8..22b17431a 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -341,7 +341,7 @@ void workingset_update_node(struct xa_node *node);
 
 /* linux/mm/page_alloc.c */
 extern unsigned long totalreserve_pages;
-extern unsigned long nr_free_buffer_pages(void);
+
 
 /* Definition of global_zone_page_state not available yet */
 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f931def63..dcdd8ebfb 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -260,7 +260,6 @@
 #include <linux/random.h>
 #include <linux/memblock.h>
 #include <linux/highmem.h>
-#include <linux/swap.h>
 #include <linux/cache.h>
 #include <linux/err.h>
 #include <linux/time.h>
-- 
2.25.1



^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH -next v2] include/linux/mm.h: move nr_free_buffer_pages from swap.h to mm.h
  2021-08-15 11:50 [PATCH -next v2] include/linux/mm.h: move nr_free_buffer_pages from swap.h to mm.h Mianhan Liu
@ 2021-08-15 15:30 ` Matthew Wilcox
  0 siblings, 0 replies; 2+ messages in thread
From: Matthew Wilcox @ 2021-08-15 15:30 UTC (permalink / raw)
  To: Mianhan Liu; +Cc: Andrew Morton, linux-mm, linux-kernel, Eric Dumazet

On Sun, Aug 15, 2021 at 07:50:57PM +0800, Mianhan Liu wrote:
> nr_free_buffer_pages could be exposed through mm.h instead of swap.h.
> The advantage of this change is that it can reduce the obsolete includes.
> For example, net/ipv4/tcp.c wouldn't need swap.h any more since it has
> already included mm.h.
> Moreover, after preprocessing all the files that use nr_free_buffer_pages,
> it turns out that those files have already included mm.h.
> Thus, we can move nr_free_buffer_pages from swap.h to mm.h safely. This change
> will not affect the compilation of other files.

In general, we're trying to move in the other direction; move things out
of mm.h and reduce the number of files which include mm.h.  That said,
I don't see what nr_free_buffer_pages() has to do with the rest of
swap.h, so I'm OK with moving this over.

That said, there are a number of other files which should have swap.h
removed.  eg:

drivers/mmc/core/mmc_test.c:#include <linux/swap.h>             /* For nr_free_buffer_pages() */

and it would be good to check the other files which use
nr_free_buffer_pages() to see if they can have swap.h removed too.

> +++ b/include/linux/mm.h
> @@ -871,6 +871,7 @@ void put_pages_list(struct list_head *pages);
>  void split_page(struct page *page, unsigned int order);
>  void folio_copy(struct folio *dst, struct folio *src);
>  
> +extern unsigned long nr_free_buffer_pages(void);

Please remove the 'extern' while you're moving this.

> +++ b/net/ipv4/tcp.c

If you're interested in cleaning up the headers, it'd be nice if less
of the networking code depended on pagemap.h ...

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2021-08-15 15:31 UTC | newest]

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2021-08-15 11:50 [PATCH -next v2] include/linux/mm.h: move nr_free_buffer_pages from swap.h to mm.h Mianhan Liu
2021-08-15 15:30 ` Matthew Wilcox

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