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* Re: [PATCH] mm: cma: Discard clean pages during contiguous allocation instead of migration
       [not found] <1347324112-14134-1-git-send-email-minchan@kernel.org>
@ 2012-09-13 19:17 ` Geert Uytterhoeven
  2012-09-13 22:19   ` Andrew Morton
  0 siblings, 1 reply; 3+ messages in thread
From: Geert Uytterhoeven @ 2012-09-13 19:17 UTC (permalink / raw)
  To: Minchan Kim
  Cc: Andrew Morton, linux-kernel, linux-mm, Kyungmin Park,
	Marek Szyprowski, Michal Nazarewicz, Rik van Riel, Mel Gorman,
	Linux-Next

On Tue, Sep 11, 2012 at 2:41 AM, Minchan Kim <minchan@kernel.org> wrote:
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -674,8 +674,10 @@ static enum page_references page_check_references(struct page *page,
>  static unsigned long shrink_page_list(struct list_head *page_list,
>                                       struct zone *zone,
>                                       struct scan_control *sc,
> +                                     enum ttu_flags ttu_flags,

"enum ttu_flags" is defined on CONFIG_MMU=y only, causing on nommu:

mm/vmscan.c:677:26: error: parameter 4 ('ttu_flags') has incomplete type
mm/vmscan.c:987:5: error: 'TTU_UNMAP' undeclared (first use in this function)
mm/vmscan.c:987:15: error: 'TTU_IGNORE_ACCESS' undeclared (first use
in this function)
mm/vmscan.c:1312:56: error: 'TTU_UNMAP' undeclared (first use in this function)

E.g.
http://kisskb.ellerman.id.au/kisskb/buildresult/7191694/ (h8300-defconfig)
http://kisskb.ellerman.id.au/kisskb/buildresult/7191858/ (sh-allnoconfig)

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] mm: cma: Discard clean pages during contiguous allocation instead of migration
  2012-09-13 19:17 ` [PATCH] mm: cma: Discard clean pages during contiguous allocation instead of migration Geert Uytterhoeven
@ 2012-09-13 22:19   ` Andrew Morton
  2012-09-14  0:10     ` Minchan Kim
  0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2012-09-13 22:19 UTC (permalink / raw)
  To: Geert Uytterhoeven
  Cc: Minchan Kim, linux-kernel, linux-mm, Kyungmin Park,
	Marek Szyprowski, Michal Nazarewicz, Rik van Riel, Mel Gorman,
	Linux-Next

On Thu, 13 Sep 2012 21:17:19 +0200
Geert Uytterhoeven <geert@linux-m68k.org> wrote:

> On Tue, Sep 11, 2012 at 2:41 AM, Minchan Kim <minchan@kernel.org> wrote:
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -674,8 +674,10 @@ static enum page_references page_check_references(struct page *page,
> >  static unsigned long shrink_page_list(struct list_head *page_list,
> >                                       struct zone *zone,
> >                                       struct scan_control *sc,
> > +                                     enum ttu_flags ttu_flags,
> 
> "enum ttu_flags" is defined on CONFIG_MMU=y only, causing on nommu:
> 
> mm/vmscan.c:677:26: error: parameter 4 ('ttu_flags') has incomplete type
> mm/vmscan.c:987:5: error: 'TTU_UNMAP' undeclared (first use in this function)
> mm/vmscan.c:987:15: error: 'TTU_IGNORE_ACCESS' undeclared (first use
> in this function)
> mm/vmscan.c:1312:56: error: 'TTU_UNMAP' undeclared (first use in this function)
> 
> E.g.
> http://kisskb.ellerman.id.au/kisskb/buildresult/7191694/ (h8300-defconfig)
> http://kisskb.ellerman.id.au/kisskb/buildresult/7191858/ (sh-allnoconfig)

hm, OK, the means by which current mainline avoids build errors is
either clever or lucky.

			switch (try_to_unmap(page, TTU_UNMAP)) {

gets preprocessed into

			switch (2) {

so the cmopiler never gets to see the TTU_ symbol at all.  Because it
happens to be inside the try_to_unmap() call.


I guess we can just make ttu_flags visible to NOMMU:


--- a/include/linux/rmap.h~mm-cma-discard-clean-pages-during-contiguous-allocation-instead-of-migration-fix-fix
+++ a/include/linux/rmap.h
@@ -71,6 +71,17 @@ struct anon_vma_chain {
 #endif
 };
 
+enum ttu_flags {
+	TTU_UNMAP = 0,			/* unmap mode */
+	TTU_MIGRATION = 1,		/* migration mode */
+	TTU_MUNLOCK = 2,		/* munlock mode */
+	TTU_ACTION_MASK = 0xff,
+
+	TTU_IGNORE_MLOCK = (1 << 8),	/* ignore mlock */
+	TTU_IGNORE_ACCESS = (1 << 9),	/* don't age */
+	TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */
+};
+
 #ifdef CONFIG_MMU
 static inline void get_anon_vma(struct anon_vma *anon_vma)
 {
@@ -164,16 +175,6 @@ int page_referenced(struct page *, int i
 int page_referenced_one(struct page *, struct vm_area_struct *,
 	unsigned long address, unsigned int *mapcount, unsigned long *vm_flags);
 
-enum ttu_flags {
-	TTU_UNMAP = 0,			/* unmap mode */
-	TTU_MIGRATION = 1,		/* migration mode */
-	TTU_MUNLOCK = 2,		/* munlock mode */
-	TTU_ACTION_MASK = 0xff,
-
-	TTU_IGNORE_MLOCK = (1 << 8),	/* ignore mlock */
-	TTU_IGNORE_ACCESS = (1 << 9),	/* don't age */
-	TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */
-};
 #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
 
 int try_to_unmap(struct page *, enum ttu_flags flags);
_

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] mm: cma: Discard clean pages during contiguous allocation instead of migration
  2012-09-13 22:19   ` Andrew Morton
@ 2012-09-14  0:10     ` Minchan Kim
  0 siblings, 0 replies; 3+ messages in thread
From: Minchan Kim @ 2012-09-14  0:10 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Geert Uytterhoeven, linux-kernel, linux-mm, Kyungmin Park,
	Marek Szyprowski, Michal Nazarewicz, Rik van Riel, Mel Gorman,
	Linux-Next

On Thu, Sep 13, 2012 at 03:19:22PM -0700, Andrew Morton wrote:
> On Thu, 13 Sep 2012 21:17:19 +0200
> Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> 
> > On Tue, Sep 11, 2012 at 2:41 AM, Minchan Kim <minchan@kernel.org> wrote:
> > > --- a/mm/vmscan.c
> > > +++ b/mm/vmscan.c
> > > @@ -674,8 +674,10 @@ static enum page_references page_check_references(struct page *page,
> > >  static unsigned long shrink_page_list(struct list_head *page_list,
> > >                                       struct zone *zone,
> > >                                       struct scan_control *sc,
> > > +                                     enum ttu_flags ttu_flags,
> > 
> > "enum ttu_flags" is defined on CONFIG_MMU=y only, causing on nommu:
> > 
> > mm/vmscan.c:677:26: error: parameter 4 ('ttu_flags') has incomplete type
> > mm/vmscan.c:987:5: error: 'TTU_UNMAP' undeclared (first use in this function)
> > mm/vmscan.c:987:15: error: 'TTU_IGNORE_ACCESS' undeclared (first use
> > in this function)
> > mm/vmscan.c:1312:56: error: 'TTU_UNMAP' undeclared (first use in this function)
> > 
> > E.g.
> > http://kisskb.ellerman.id.au/kisskb/buildresult/7191694/ (h8300-defconfig)
> > http://kisskb.ellerman.id.au/kisskb/buildresult/7191858/ (sh-allnoconfig)
> 
> hm, OK, the means by which current mainline avoids build errors is
> either clever or lucky.
> 
> 			switch (try_to_unmap(page, TTU_UNMAP)) {
> 
> gets preprocessed into
> 
> 			switch (2) {
> 
> so the cmopiler never gets to see the TTU_ symbol at all.  Because it
> happens to be inside the try_to_unmap() call.
> 
> 
> I guess we can just make ttu_flags visible to NOMMU:

I agree.

Geert, Andrew
Thanks for the reporting and quick fix!

-- 
Kind regards,
Minchan Kim

^ permalink raw reply	[flat|nested] 3+ messages in thread
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     [not found] <1347324112-14134-1-git-send-email-minchan@kernel.org>
2012-09-13 19:17 ` [PATCH] mm: cma: Discard clean pages during contiguous allocation instead of migration Geert Uytterhoeven
2012-09-13 22:19   ` Andrew Morton
2012-09-14  0:10     ` Minchan Kim

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