linux-kernel - [PATCH v1 6/6] powernv/memtrace: use __GFP_ZERO with alloc_contig

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Message-ID: <20241202125812.561028-7-david@redhat.com>
Date: Mon,  2 Dec 2024 13:58:12 +0100
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org,
	linuxppc-dev@...ts.ozlabs.org,
	David Hildenbrand <david@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Oscar Salvador <osalvador@...e.de>,
	Zi Yan <ziy@...dia.com>,
	Michael Ellerman <mpe@...erman.id.au>,
	Nicholas Piggin <npiggin@...il.com>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	Naveen N Rao <naveen@...nel.org>,
	Madhavan Srinivasan <maddy@...ux.ibm.com>
Subject: [PATCH v1 6/6] powernv/memtrace: use __GFP_ZERO with alloc_contig_pages()

alloc_contig_pages()->alloc_contig_range() now supports __GFP_ZERO,
so let's use that instead to resolve our TODO.

Signed-off-by: David Hildenbrand <david@...hat.com>
---
 arch/powerpc/platforms/powernv/memtrace.c | 31 +++++------------------
 1 file changed, 6 insertions(+), 25 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index 877720c64515..4ac9808e55a4 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -88,26 +88,6 @@ static void flush_dcache_range_chunked(unsigned long start, unsigned long stop,
 	}
 }
 
-static void memtrace_clear_range(unsigned long start_pfn,
-				 unsigned long nr_pages)
-{
-	unsigned long pfn;
-
-	/* As HIGHMEM does not apply, use clear_page() directly. */
-	for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++) {
-		if (IS_ALIGNED(pfn, PAGES_PER_SECTION))
-			cond_resched();
-		clear_page(__va(PFN_PHYS(pfn)));
-	}
-	/*
-	 * Before we go ahead and use this range as cache inhibited range
-	 * flush the cache.
-	 */
-	flush_dcache_range_chunked((unsigned long)pfn_to_kaddr(start_pfn),
-				   (unsigned long)pfn_to_kaddr(start_pfn + nr_pages),
-				   FLUSH_CHUNK_SIZE);
-}
-
 static u64 memtrace_alloc_node(u32 nid, u64 size)
 {
 	const unsigned long nr_pages = PHYS_PFN(size);
@@ -119,17 +99,18 @@ static u64 memtrace_alloc_node(u32 nid, u64 size)
 	 * by alloc_contig_pages().
 	 */
 	page = alloc_contig_pages(nr_pages, GFP_KERNEL | __GFP_THISNODE |
-				  __GFP_NOWARN, nid, NULL);
+				  __GFP_NOWARN | __GFP_ZERO, nid, NULL);
 	if (!page)
 		return 0;
 	start_pfn = page_to_pfn(page);
 
 	/*
-	 * Clear the range while we still have a linear mapping.
-	 *
-	 * TODO: use __GFP_ZERO with alloc_contig_pages() once supported.
+	 * Before we go ahead and use this range as cache inhibited range
+	 * flush the cache.
 	 */
-	memtrace_clear_range(start_pfn, nr_pages);
+	flush_dcache_range_chunked((unsigned long)pfn_to_kaddr(start_pfn),
+				   (unsigned long)pfn_to_kaddr(start_pfn + nr_pages),
+				   FLUSH_CHUNK_SIZE);
 
 	/*
 	 * Set pages PageOffline(), to indicate that nobody (e.g., hibernation,
-- 
2.47.1