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From: Oscar Salvador <osalvador@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
	Michal Hocko <mhocko@kernel.org>, Zi Yan <ziy@nvidia.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Oscar Salvador <osalvador@suse.de>
Subject: [PATCH v6 2/4] x86/vmemmap: Drop handling of 1GB vmemmap ranges
Date: Tue,  9 Mar 2021 22:40:48 +0100	[thread overview]
Message-ID: <20210309214050.4674-3-osalvador@suse.de> (raw)
In-Reply-To: <20210309214050.4674-1-osalvador@suse.de>

There is no code to allocate 1GB pages when mapping the vmemmap range
as this might waste some memory and requires more complexity which
is not really worth.
Drop the dead code both for the aligned and unaligned cases and leave
only the direct map handling.

Signed-off-by: Oscar Salvador <osalvador@suse.de>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.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


  parent reply	other threads:[~2021-03-09 21:41 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-09 21:40 [PATCH v6 0/4] Cleanup and fixups for vmemmap handling Oscar Salvador
2021-03-09 21:40 ` [PATCH v6 1/4] x86/vmemmap: Drop handling of 4K unaligned vmemmap range Oscar Salvador
2021-03-09 21:40 ` Oscar Salvador [this message]
2021-03-09 21:40 ` [PATCH v6 3/4] x86/vmemmap: Handle unpopulated sub-pmd ranges Oscar Salvador
2021-03-10  6:07   ` Naresh Kamboju
2021-03-10  6:07     ` Naresh Kamboju
2021-03-10  7:24     ` Oscar Salvador
2021-03-11 21:29   ` Dave Hansen
2021-03-11 21:48     ` Oscar Salvador
2021-03-30  2:29       ` Matthew Wilcox
2021-04-02 17:58         ` Oscar Salvador
2021-03-09 21:40 ` [PATCH v6 4/4] x86/vmemmap: Optimize for consecutive sections in partial populated PMDs Oscar Salvador

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