[PATCH v2 8/9] powerpc/mem: Inline flush_dcache_page()

From: Christophe Leroy
Date: Thu Apr 08 2021 - 11:31:16 EST


flush_dcache_page() is only a few lines, it is worth
inlining.

ia64, csky, mips, openrisc and riscv have a similar
flush_dcache_page() and inline it.

On pmac32_defconfig, we get a small size reduction.
On ppc64_defconfig, we get a very small size increase.

In both case that's in the noise (less than 0.1%).

text data bss dec hex filename
18991155 5934744 1497624 26423523 19330e3 vmlinux64.before
18994829 5936732 1497624 26429185 1934701 vmlinux64.after
9150963 2467502 184548 11803013 b41985 vmlinux32.before
9149689 2467302 184548 11801539 b413c3 vmlinux32.after

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
arch/powerpc/include/asm/cacheflush.h | 14 +++++++++++++-
arch/powerpc/mm/cacheflush.c | 15 ---------------
2 files changed, 13 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/include/asm/cacheflush.h b/arch/powerpc/include/asm/cacheflush.h
index 9110489ea411..7564dd4fd12b 100644
--- a/arch/powerpc/include/asm/cacheflush.h
+++ b/arch/powerpc/include/asm/cacheflush.h
@@ -30,7 +30,19 @@ static inline void flush_cache_vmap(unsigned long start, unsigned long end)
#endif /* CONFIG_PPC_BOOK3S_64 */

#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
-extern void flush_dcache_page(struct page *page);
+/*
+ * This is called when a page has been modified by the kernel.
+ * It just marks the page as not i-cache clean. We do the i-cache
+ * flush later when the page is given to a user process, if necessary.
+ */
+static inline void flush_dcache_page(struct page *page)
+{
+ if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
+ return;
+ /* avoid an atomic op if possible */
+ if (test_bit(PG_dcache_clean, &page->flags))
+ clear_bit(PG_dcache_clean, &page->flags);
+}

void flush_icache_range(unsigned long start, unsigned long stop);
#define flush_icache_range flush_icache_range
diff --git a/arch/powerpc/mm/cacheflush.c b/arch/powerpc/mm/cacheflush.c
index abeef69ed4e4..d9eafa077c09 100644
--- a/arch/powerpc/mm/cacheflush.c
+++ b/arch/powerpc/mm/cacheflush.c
@@ -121,21 +121,6 @@ static void flush_dcache_icache_phys(unsigned long physaddr)
}
#endif

-/*
- * This is called when a page has been modified by the kernel.
- * It just marks the page as not i-cache clean. We do the i-cache
- * flush later when the page is given to a user process, if necessary.
- */
-void flush_dcache_page(struct page *page)
-{
- if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
- return;
- /* avoid an atomic op if possible */
- if (test_bit(PG_dcache_clean, &page->flags))
- clear_bit(PG_dcache_clean, &page->flags);
-}
-EXPORT_SYMBOL(flush_dcache_page);
-
/**
* __flush_dcache_icache(): Flush a particular page from the data cache to RAM.
* Note: this is necessary because the instruction cache does *not*
--
2.25.0