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From: Stuart Hayes <stuart.w.hayes@gmail.com>
To: tglx@linutronix.de, mingo@redhat.com, "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, prarit@redhat.com
Subject: Fwd: [PATCH] x86: Use larger chunks in mtrr_cleanup
Date: Mon, 31 Aug 2015 11:05:33 -0500	[thread overview]
Message-ID: <55E47B4D.1050103@gmail.com> (raw)
In-Reply-To: <55E477DE.2060106@gmail.com>

Increase the range of chunk sizes tried in mtrr_cleanup() so it is able
to map large memory configs into MTRRs.

Currently, mtrr_cleanup() will fail with large memory configurations,
because it limits chunk_size to 2GB, which means that each MTRR can only
cover 2GB of memory.  With a memory size of, say, 256GB, and ten variable
MTRRs (such as some recent Intel CPUs have), it is not possible to set up
the MTRRs to cover all of memory.

Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com>
---
--- linux-4.2-rc7/arch/x86/kernel/cpu/mtrr/cleanup.c.orig	2015-08-16 18:34:13.000000000 -0500
+++ linux-4.2-rc7/arch/x86/kernel/cpu/mtrr/cleanup.c	2015-08-27 12:29:51.908579247 -0500
@@ -517,10 +517,11 @@ struct mtrr_cleanup_result {
 
 /*
  * gran_size: 64K, 128K, 256K, 512K, 1M, 2M, ..., 2G
- * chunk size: gran_size, ..., 2G
- * so we need (1+16)*8
+ * chunk size: gran_size, ..., 2G, ..., 1<<address_bits
+ *   (for 32 address bits, we need 136)
+ *   (for 40 address bits, we need 264)
  */
-#define NUM_RESULT	136
+#define NUM_RESULT	264
 #define PSHIFT		(PAGE_SHIFT - 10)
 
 static struct mtrr_cleanup_result __initdata result[NUM_RESULT];
@@ -751,7 +752,7 @@ int __init mtrr_cleanup(unsigned address
 	memset(result, 0, sizeof(result));
 	for (gran_size = (1ULL<<16); gran_size < (1ULL<<32); gran_size <<= 1) {
 
-		for (chunk_size = gran_size; chunk_size < (1ULL<<32);
+		for (chunk_size = gran_size; chunk_size < (1ULL<<address_bits);
 		     chunk_size <<= 1) {
 
 			if (i >= NUM_RESULT)




       reply	other threads:[~2015-08-31 16:05 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <55E477DE.2060106@gmail.com>
2015-08-31 16:05 ` Stuart Hayes [this message]
2015-09-03  2:45   ` Luis R. Rodriguez
2015-09-03 12:17     ` Prarit Bhargava
2015-09-03 17:59       ` Luis R. Rodriguez
2015-09-03 18:10         ` Prarit Bhargava
2015-09-03 18:40           ` Luis R. Rodriguez
2015-09-03 19:22             ` Toshi Kani
2015-09-03 19:51               ` Luis R. Rodriguez
2015-09-03 21:31                 ` Toshi Kani
2015-09-03 22:07                   ` Luis R. Rodriguez
2015-09-03 22:25                     ` Toshi Kani
2015-09-03 22:45                       ` Luis R. Rodriguez
2015-09-03 23:21                         ` Toshi Kani
2015-09-03 23:54                           ` Luis R. Rodriguez
2015-09-04  0:48                             ` Toshi Kani
2015-09-04  1:40                               ` Luis R. Rodriguez
2015-09-04 14:56                                 ` Toshi Kani
2015-09-04  6:51                             ` Jan Beulich
2015-09-14 14:46       ` Stuart Hayes
2015-11-05 19:14         ` Yinghai Lu
2015-11-05 19:43           ` Luis R. Rodriguez
2016-03-16 20:20             ` Luis R. Rodriguez
2016-03-29 17:07               ` Luis R. Rodriguez

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