riscv/mm: hugepage's PG_dcache_clean flag is only set in head page

HugeTLB pages are always fully mapped, so only setting head page's PG_dcache_clean flag is enough. Signed-off-by: Tong Tiangen <[email protected]> Link: https://lore.kernel.org/lkml/[email protected]/ Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Palmer Dabbelt <[email protected]>
torvalds · Dec 2, 2022 · d33deda · d33deda
1 parent 6925ba3
commit d33deda
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diff --git a/arch/riscv/include/asm/cacheflush.h b/arch/riscv/include/asm/cacheflush.h
@@ -17,6 +17,13 @@ static inline void local_flush_icache_all(void)
 
 static inline void flush_dcache_page(struct page *page)
 {
+	/*
+	 * HugeTLB pages are always fully mapped and only head page will be
+	 * set PG_dcache_clean (see comments in flush_icache_pte()).
+	 */
+	if (PageHuge(page))
+		page = compound_head(page);
+
 	if (test_bit(PG_dcache_clean, &page->flags))
 		clear_bit(PG_dcache_clean, &page->flags);
 }

diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
@@ -82,6 +82,13 @@ void flush_icache_pte(pte_t pte)
 {
 	struct page *page = pte_page(pte);
 
+	/*
+	 * HugeTLB pages are always fully mapped, so only setting head page's
+	 * PG_dcache_clean flag is enough.
+	 */
+	if (PageHuge(page))
+		page = compound_head(page);
+
 	if (!test_and_set_bit(PG_dcache_clean, &page->flags))
 		flush_icache_all();
 }