linux-kernel - [PATCH 14/15] x86/numa: remove redundant iteration over memblock.reserved

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Message-Id: <20200728051153.1590-15-rppt@kernel.org>
Date:   Tue, 28 Jul 2020 08:11:52 +0300
From:   Mike Rapoport <rppt@...nel.org>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Andy Lutomirski <luto@...nel.org>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Borislav Petkov <bp@...en8.de>,
        Catalin Marinas <catalin.marinas@....com>,
        Christoph Hellwig <hch@....de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Max Filippov <jcmvbkbc@...il.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Michal Simek <monstr@...str.eu>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        Mike Rapoport <rppt@...nel.org>,
        Palmer Dabbelt <palmer@...belt.com>,
        Paul Mackerras <paulus@...ba.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Russell King <linux@...linux.org.uk>,
        Stafford Horne <shorne@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Will Deacon <will@...nel.org>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        clang-built-linux@...glegroups.com,
        iommu@...ts.linux-foundation.org,
        linux-arm-kernel@...ts.infradead.org, linux-c6x-dev@...ux-c6x.org,
        linux-kernel@...r.kernel.org, linux-mips@...r.kernel.org,
        linux-mm@...ck.org, linux-riscv@...ts.infradead.org,
        linux-s390@...r.kernel.org, linux-sh@...r.kernel.org,
        linux-xtensa@...ux-xtensa.org, linuxppc-dev@...ts.ozlabs.org,
        openrisc@...ts.librecores.org, sparclinux@...r.kernel.org,
        uclinux-h8-devel@...ts.sourceforge.jp, x86@...nel.org
Subject: [PATCH 14/15] x86/numa: remove redundant iteration over memblock.reserved

From: Mike Rapoport <rppt@...ux.ibm.com>

numa_clear_kernel_node_hotplug() function first traverses numa_meminfo
regions to set node ID in memblock.reserved and than traverses
memblock.reserved to update reserved_nodemask to include node IDs that were
set in the first loop.

Remove redundant traversal over memblock.reserved and update
reserved_nodemask while iterating over numa_meminfo.

Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
---
 arch/x86/mm/numa.c | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 8ee952038c80..4078abd33938 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -498,31 +498,25 @@ static void __init numa_clear_kernel_node_hotplug(void)
 	 * and use those ranges to set the nid in memblock.reserved.
 	 * This will split up the memblock regions along node
 	 * boundaries and will set the node IDs as well.
+	 *
+	 * The nid will also be set in reserved_nodemask which is later
+	 * used to clear MEMBLOCK_HOTPLUG flag.
+	 *
+	 * [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
+	 *   numa_meminfo might not include all memblock.reserved
+	 *   memory ranges, because quirks such as trim_snb_memory()
+	 *   reserve specific pages for Sandy Bridge graphics.
+	 *   These ranges will remain with nid == MAX_NUMNODES. ]
 	 */
 	for (i = 0; i < numa_meminfo.nr_blks; i++) {
 		struct numa_memblk *mb = numa_meminfo.blk + i;
 		int ret;
 
 		ret = memblock_set_node(mb->start, mb->end - mb->start, &memblock.reserved, mb->nid);
+		node_set(mb->nid, reserved_nodemask);
 		WARN_ON_ONCE(ret);
 	}
 
-	/*
-	 * Now go over all reserved memblock regions, to construct a
-	 * node mask of all kernel reserved memory areas.
-	 *
-	 * [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
-	 *   numa_meminfo might not include all memblock.reserved
-	 *   memory ranges, because quirks such as trim_snb_memory()
-	 *   reserve specific pages for Sandy Bridge graphics. ]
-	 */
-	for_each_memblock(reserved, mb_region) {
-		int nid = memblock_get_region_node(mb_region);
-
-		if (nid != MAX_NUMNODES)
-			node_set(nid, reserved_nodemask);
-	}
-
 	/*
 	 * Finally, clear the MEMBLOCK_HOTPLUG flag for all memory
 	 * belonging to the reserved node mask.
-- 
2.26.2