From 66b4aaf7335c9e7f59ba93a45379ba2bbfe1b913 Mon Sep 17 00:00:00 2001
From: Wei Yang <richard.weiyang@gmail.com>
Date: Mon, 1 Jul 2024 01:34:09 +0000
Subject: kernel/fork.c: get totalram_pages from memblock to calculate
 max_threads

Since we plan to move the accounting into __free_pages_core(),
totalram_pages may not represent the total usable pages on system at this
point when defer_init is enabled.

Instead we can get the total usable pages from memblock directly.

Link: https://lkml.kernel.org/r/20240701013410.17260-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 kernel/fork.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index 279efadabbf2..60309c6d6074 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -44,6 +44,7 @@
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/mm_inline.h>
+#include <linux/memblock.h>
 #include <linux/nsproxy.h>
 #include <linux/capability.h>
 #include <linux/cpu.h>
@@ -999,7 +1000,7 @@ void __init __weak arch_task_cache_init(void) { }
 static void set_max_threads(unsigned int max_threads_suggested)
 {
 	u64 threads;
-	unsigned long nr_pages = totalram_pages();
+	unsigned long nr_pages = PHYS_PFN(memblock_phys_mem_size() - memblock_reserved_size());
 
 	/*
 	 * The number of threads shall be limited such that the thread
-- 
cgit