linux-kernel - [PATCH 2/3] asm-generic/tlb: stub out p4d_free_tlb() if __PAGETABLE_P4D

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Message-Id: <20191009222658.961-3-vgupta@synopsys.com>
Date:   Wed,  9 Oct 2019 15:26:57 -0700
From:   Vineet Gupta <Vineet.Gupta1@...opsys.com>
To:     linux-mm@...ck.org
Cc:     linux-snps-arc@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-arch@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        Will Deacon <will@...nel.org>,
        "Aneesh Kumar K . V" <aneesh.kumar@...ux.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Nick Piggin <npiggin@...il.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Vineet Gupta <Vineet.Gupta1@...opsys.com>
Subject: [PATCH 2/3] asm-generic/tlb: stub out p4d_free_tlb() if __PAGETABLE_P4D_FOLDED ...

... independent of __ARCH_HAS_5LEVEL_HACK

This came up when removing __ARCH_HAS_5LEVEL_HACK for ARC as code bloat
from p4d_free_tlb() despite pud being folded (with 2 levels on ARC)

| bloat-o-meter2 vmlinux-C-elide-pud_free_tlb vmlinux-D-elide-p4d_free_tlb
| add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-104 (-104)
| function                                     old     new   delta
| free_pgd_range                               552     422    -130
| Total: Before=4137172, After=4137042, chg -1.000000%

Signed-off-by: Vineet Gupta <vgupta@...opsys.com>
---
 include/asm-generic/5level-fixup.h | 2 --
 include/asm-generic/tlb.h          | 4 +++-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h
index f6947da70d71..c855b5cf4425 100644
--- a/include/asm-generic/5level-fixup.h
+++ b/include/asm-generic/5level-fixup.h
@@ -48,8 +48,6 @@ static inline int p4d_present(p4d_t p4d)
 #define __p4d(x)			__pgd(x)
 #define set_p4d(p4dp, p4d)		set_pgd(p4dp, p4d)
 
-#undef p4d_free_tlb
-#define p4d_free_tlb(tlb, x, addr)	do { } while (0)
 #define p4d_free(mm, x)			do { } while (0)
 #define __p4d_free_tlb(tlb, x, addr)	do { } while (0)
 
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index 1f83188cb331..f3dad87f4ecc 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -598,7 +598,7 @@ static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vm
 #define pud_free_tlb(tlb, pudp, address)	do { } while (0)
 #endif
 
-#ifndef __ARCH_HAS_5LEVEL_HACK
+#ifndef __PAGETABLE_P4D_FOLDED
 #ifndef p4d_free_tlb
 #define p4d_free_tlb(tlb, pudp, address)			\
 	do {							\
@@ -607,6 +607,8 @@ static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vm
 		__p4d_free_tlb(tlb, pudp, address);		\
 	} while (0)
 #endif
+#else
+#define p4d_free_tlb(tlb, pudp, address)	do { } while (0)
 #endif
 
 #endif /* CONFIG_MMU */
-- 
2.20.1