linux-kernel - [PATCH v3 2/3] x86/vmemmap: Drop handling of 1GB vmemmap ranges

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Message-Id: <20210204134325.7237-3-osalvador@suse.de>
Date:   Thu,  4 Feb 2021 14:43:24 +0100
From:   Oscar Salvador <osalvador@...e.de>
To:     akpm@...ux-foundation.org
Cc:     David Hildenbrand <david@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H . Peter Anvin" <hpa@...or.com>,
        Michal Hocko <mhocko@...nel.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Oscar Salvador <osalvador@...e.de>
Subject: [PATCH v3 2/3] x86/vmemmap: Drop handling of 1GB vmemmap ranges

We never get to allocate 1GB pages when mapping the vmemmap range.
Drop the dead code both for the aligned and unaligned cases and leave
only the direct map handling.

Signed-off-by: Oscar Salvador <osalvador@...e.de>
Suggested-by: David Hildenbrand <david@...hat.com>
---
 arch/x86/mm/init_64.c | 35 +++++++----------------------------
 1 file changed, 7 insertions(+), 28 deletions(-)

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index b0e1d215c83e..9ecb3c488ac8 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1062,7 +1062,6 @@ remove_pud_table(pud_t *pud_start, unsigned long addr, unsigned long end,
 	unsigned long next, pages = 0;
 	pmd_t *pmd_base;
 	pud_t *pud;
-	void *page_addr;
 
 	pud = pud_start + pud_index(addr);
 	for (; addr < end; addr = next, pud++) {
@@ -1071,33 +1070,13 @@ remove_pud_table(pud_t *pud_start, unsigned long addr, unsigned long end,
 		if (!pud_present(*pud))
 			continue;
 
-		if (pud_large(*pud)) {
-			if (IS_ALIGNED(addr, PUD_SIZE) &&
-			    IS_ALIGNED(next, PUD_SIZE)) {
-				if (!direct)
-					free_pagetable(pud_page(*pud),
-						       get_order(PUD_SIZE));
-
-				spin_lock(&init_mm.page_table_lock);
-				pud_clear(pud);
-				spin_unlock(&init_mm.page_table_lock);
-				pages++;
-			} else {
-				/* If here, we are freeing vmemmap pages. */
-				memset((void *)addr, PAGE_INUSE, next - addr);
-
-				page_addr = page_address(pud_page(*pud));
-				if (!memchr_inv(page_addr, PAGE_INUSE,
-						PUD_SIZE)) {
-					free_pagetable(pud_page(*pud),
-						       get_order(PUD_SIZE));
-
-					spin_lock(&init_mm.page_table_lock);
-					pud_clear(pud);
-					spin_unlock(&init_mm.page_table_lock);
-				}
-			}
-
+		if (pud_large(*pud) &&
+		    IS_ALIGNED(addr, PUD_SIZE) &&
+		    IS_ALIGNED(next, PUD_SIZE)) {
+			spin_lock(&init_mm.page_table_lock);
+			pud_clear(pud);
+			spin_unlock(&init_mm.page_table_lock);
+			pages++;
 			continue;
 		}
 
-- 
2.26.2