linux-kernel - Re: [PATCH v6 10/18] sh/tlb: Convert SH to generic mmu

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Date:   Wed, 4 Dec 2019 14:34:54 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Will Deacon <will.deacon@....com>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Nicholas Piggin <npiggin@...il.com>,
        Linux-Arch <linux-arch@...r.kernel.org>,
        Linux MM <linux-mm@...ck.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Russell King <linux@...linux.org.uk>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Rik van Riel <riel@...riel.com>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>,
        Linux-sh list <linux-sh@...r.kernel.org>,
        Guenter Roeck <linux@...ck-us.net>
Subject: Re: [PATCH v6 10/18] sh/tlb: Convert SH to generic mmu_gather

On Wed, Dec 04, 2019 at 01:32:58PM +0100, Geert Uytterhoeven wrote:

> > Does the below help?
> 
> Unfortunately not.
> 
> > diff --git a/arch/sh/include/asm/pgalloc.h b/arch/sh/include/asm/pgalloc.h
> > index 22d968bfe9bb..73a2c00de6c5 100644
> > --- a/arch/sh/include/asm/pgalloc.h
> > +++ b/arch/sh/include/asm/pgalloc.h
> > @@ -36,9 +36,8 @@ do {                                                  \
> >  #if CONFIG_PGTABLE_LEVELS > 2
> >  #define __pmd_free_tlb(tlb, pmdp, addr)                        \
> >  do {                                                   \
> > -       struct page *page = virt_to_page(pmdp);         \
> > -       pgtable_pmd_page_dtor(page);                    \
> > -       tlb_remove_page((tlb), page);                   \
> > +       pgtable_pmd_page_dtor(pmdp);                    \
> 
> expected ‘struct page *’ but argument is of type ‘pmd_t * {aka struct
> <anonymous> *}’
> 
> > +       tlb_remove_page((tlb), (pmdp));                 \
> 
> likewise

Duh.. clearly I misplaced my SH cross compiler. Let me go find it.

Also, looking at pgtable.c the pmd_t* actually comes from a kmemcach()
and should probably use pmd_free() (which is what the old code did too).

Also, since SH doesn't have ARCH_ENABLE_SPLIT_PMD_PTLOCK, it will never
need pgtable_pmd_page_dtor().

The below seems to build se7722_defconfig using sh4-linux-. That is, the
build fails, on 'node_reclaim_distance', not pgtable stuff.

Does this fare better?

---
 arch/sh/include/asm/pgalloc.h | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/sh/include/asm/pgalloc.h b/arch/sh/include/asm/pgalloc.h
index 22d968bfe9bb..c910e5bcde62 100644
--- a/arch/sh/include/asm/pgalloc.h
+++ b/arch/sh/include/asm/pgalloc.h
@@ -36,9 +36,7 @@ do {							\
 #if CONFIG_PGTABLE_LEVELS > 2
 #define __pmd_free_tlb(tlb, pmdp, addr)			\
 do {							\
-	struct page *page = virt_to_page(pmdp);		\
-	pgtable_pmd_page_dtor(page);			\
-	tlb_remove_page((tlb), page);			\
+	pmd_free((tlb)->mm, (pmdp));			\
 } while (0);
 #endif