linux-kernel - [PATCH 5/5] tile: query dynamic DEBUG

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Date:	Thu,  4 Feb 2016 14:56:26 +0900
From:	Joonsoo Kim <js1304@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	David Rientjes <rientjes@...gle.com>,
	Christian Borntraeger <borntraeger@...ibm.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Takashi Iwai <tiwai@...e.com>,
	Chris Metcalf <cmetcalf@...hip.com>,
	Christoph Lameter <cl@...ux.com>, linux-api@...r.kernel.org,
	Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: [PATCH 5/5] tile: query dynamic DEBUG_PAGEALLOC setting

We can disable debug_pagealloc processing even if the code is complied
with CONFIG_DEBUG_PAGEALLOC. This patch changes the code to query
whether it is enabled or not in runtime.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@....com>
---
 arch/tile/mm/init.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
index d4e1fc4..a0582b7 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c
@@ -896,17 +896,15 @@ void __init pgtable_cache_init(void)
 		panic("pgtable_cache_init(): Cannot create pgd cache");
 }
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
-static long __write_once initfree;
-#else
 static long __write_once initfree = 1;
-#endif
+static bool __write_once set_initfree_done;
 
 /* Select whether to free (1) or mark unusable (0) the __init pages. */
 static int __init set_initfree(char *str)
 {
 	long val;
 	if (kstrtol(str, 0, &val) == 0) {
+		set_initfree_done = true;
 		initfree = val;
 		pr_info("initfree: %s free init pages\n",
 			initfree ? "will" : "won't");
@@ -919,6 +917,11 @@ static void free_init_pages(char *what, unsigned long begin, unsigned long end)
 {
 	unsigned long addr = (unsigned long) begin;
 
+	/* Prefer user request first */
+	if (!set_initfree_done) {
+		if (debug_pagealloc_enabled())
+			initfree = 0;
+	}
 	if (kdata_huge && !initfree) {
 		pr_warn("Warning: ignoring initfree=0: incompatible with kdata=huge\n");
 		initfree = 1;
-- 
1.9.1