linux-kernel - [PATCH v4 2/3] x86/vmemmap: Drop handling of 1GB vmemmap ranges

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Message-Id: <20210301083230.30924-3-osalvador@suse.de>
Date:   Mon,  1 Mar 2021 09:32:29 +0100
From:   Oscar Salvador <osalvador@...e.de>
To:     Andrew Morton <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 v4 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>
Reviewed-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;
 		}
 
-- 
2.16.3