linux-kernel - [PATCH V2] powerpc/pseries/svm: Drop unused align argument in alloc_shared

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Message-Id: <20200612142953.135408-1-sathnaga@linux.vnet.ibm.com>
Date:   Fri, 12 Jun 2020 19:59:53 +0530
From:   Satheesh Rajendran <sathnaga@...ux.vnet.ibm.com>
To:     linuxppc-dev@...ts.ozlabs.org
Cc:     Satheesh Rajendran <sathnaga@...ux.vnet.ibm.com>,
        linux-kernel@...r.kernel.org,
        Thiago Jung Bauermann <bauerman@...ux.ibm.com>,
        Ram Pai <linuxram@...ibm.com>,
        Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>,
        Laurent Dufour <ldufour@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH V2] powerpc/pseries/svm: Drop unused align argument in alloc_shared_lppaca() function

Argument "align" in alloc_shared_lppaca() was unused inside the
function. Let's drop it and update code comment for page alignment.

Cc: linux-kernel@...r.kernel.org
Cc: Thiago Jung Bauermann <bauerman@...ux.ibm.com>
Cc: Ram Pai <linuxram@...ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>
Cc: Laurent Dufour <ldufour@...ux.ibm.com>
Cc: Michael Ellerman <mpe@...erman.id.au>
Reviewed-by: Thiago Jung Bauermann <bauerman@...ux.ibm.com>
Signed-off-by: Satheesh Rajendran <sathnaga@...ux.vnet.ibm.com>
---

V2:
Added reviewed by Thiago.
Dropped align argument as per Michael suggest.
Modified commit msg.

V1: http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20200609113909.17236-1-sathnaga@linux.vnet.ibm.com/
---
 arch/powerpc/kernel/paca.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index 8d96169c597e..a174d64d9b4d 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -57,8 +57,8 @@ static void *__init alloc_paca_data(unsigned long size, unsigned long align,
 
 #define LPPACA_SIZE 0x400
 
-static void *__init alloc_shared_lppaca(unsigned long size, unsigned long align,
-					unsigned long limit, int cpu)
+static void *__init alloc_shared_lppaca(unsigned long size, unsigned long limit,
+					int cpu)
 {
 	size_t shared_lppaca_total_size = PAGE_ALIGN(nr_cpu_ids * LPPACA_SIZE);
 	static unsigned long shared_lppaca_size;
@@ -68,6 +68,12 @@ static void *__init alloc_shared_lppaca(unsigned long size, unsigned long align,
 	if (!shared_lppaca) {
 		memblock_set_bottom_up(true);
 
+		/* See Documentation/powerpc/ultravisor.rst for mode details
+		 *
+		 * UV/HV data share is in PAGE granularity, In order to
+		 * minimize the number of pages shared and maximize the
+		 * use of a page, let's use page align.
+		 */
 		shared_lppaca =
 			memblock_alloc_try_nid(shared_lppaca_total_size,
 					       PAGE_SIZE, MEMBLOCK_LOW_LIMIT,
@@ -122,7 +128,7 @@ static struct lppaca * __init new_lppaca(int cpu, unsigned long limit)
 		return NULL;
 
 	if (is_secure_guest())
-		lp = alloc_shared_lppaca(LPPACA_SIZE, 0x400, limit, cpu);
+		lp = alloc_shared_lppaca(LPPACA_SIZE, limit, cpu);
 	else
 		lp = alloc_paca_data(LPPACA_SIZE, 0x400, limit, cpu);
 
-- 
2.26.2