linux-kernel - Re: [PATCH 6/4] x86/mm: Simplify probe_page_size

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Date:	Thu, 5 Mar 2015 09:47:05 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	Juergen Gross <jgross@...e.com>
Cc:	"Luis R. Rodriguez" <mcgrof@...not-panic.com>,
	gregkh@...uxfoundation.org, akpm@...ux-foundation.org,
	tony@...mide.com, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, luto@...capital.net, toshi.kani@...com,
	dave.hansen@...ux.intel.com, JBeulich@...e.com, pavel@....cz,
	qiuxishi@...wei.com, david.vrabel@...rix.com, bp@...e.de,
	vbabka@...e.cz, iamjoonsoo.kim@....com, decui@...rosoft.com,
	linux-kernel@...r.kernel.org, x86@...nel.org, julia.lawall@...6.fr,
	"Luis R. Rodriguez" <mcgrof@...e.com>
Subject: Re: [PATCH 6/4] x86/mm: Simplify probe_page_size_mask()


* Juergen Gross <jgross@...e.com> wrote:

> On 03/05/2015 08:27 AM, Ingo Molnar wrote:
> >
> >Now that we've simplified the gbpages config space, move the
> >'page_size_mask' initialization into probe_page_size_mask(), right
> >next to the PSE and PGE enablement lines.
> >
> >Cc: Luis R. Rodriguez <mcgrof@...e.com>
> >Cc: Andrew Morton <akpm@...ux-foundation.org>
> >Cc: Andy Lutomirski <luto@...capital.net>
> >Cc: Borislav Petkov <bp@...en8.de>
> >Cc: Borislav Petkov <bp@...e.de>
> >Cc: Dave Hansen <dave.hansen@...ux.intel.com>
> >Cc: David Vrabel <david.vrabel@...rix.com>
> >Cc: Dexuan Cui <decui@...rosoft.com>
> >Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> >Cc: H. Peter Anvin <hpa@...or.com>
> >Cc: JBeulich@...e.com
> >Cc: Jan Beulich <JBeulich@...e.com>
> >Cc: Joonsoo Kim <iamjoonsoo.kim@....com>
> >Cc: Juergen Gross <jgross@...e.com>
> >Cc: Linus Torvalds <torvalds@...ux-foundation.org>
> >Cc: Pavel Machek <pavel@....cz>
> >Cc: Thomas Gleixner <tglx@...utronix.de>
> >Cc: Tony Lindgren <tony@...mide.com>
> >Cc: Toshi Kani <toshi.kani@...com>
> >Cc: Vlastimil Babka <vbabka@...e.cz>
> >Cc: Xishi Qiu <qiuxishi@...wei.com>
> >Cc: julia.lawall@...6.fr
> >Signed-off-by: Ingo Molnar <mingo@...nel.org>
> >---
> >  arch/x86/mm/init.c | 23 ++++++++++-------------
> >  1 file changed, 10 insertions(+), 13 deletions(-)
> >
> >diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> >index 8704153f2675..6dc85d51cd98 100644
> >--- a/arch/x86/mm/init.c
> >+++ b/arch/x86/mm/init.c
> >@@ -131,29 +131,18 @@ void  __init early_alloc_pgt_buf(void)
> >
> >  int after_bootmem;
> >
> >-static int page_size_mask;
> >-
> >  early_param_on_off("gbpages", "nogbpages", direct_gbpages, CONFIG_X86_DIRECT_GBPAGES);
> >
> >-static void __init init_gbpages(void)
> >-{
> >-	if (direct_gbpages && cpu_has_gbpages) {
> >-		printk(KERN_INFO "Using GB pages for direct mapping\n");
> >-		page_size_mask |= 1 << PG_LEVEL_1G;
> >-	} else
> >-		direct_gbpages = 0;
> >-}
> >-
> >  struct map_range {
> >  	unsigned long start;
> >  	unsigned long end;
> >  	unsigned page_size_mask;
> >  };
> >
> >+static int page_size_mask;
> >+
> >  static void __init probe_page_size_mask(void)
> >  {
> >-	init_gbpages();
> >-
> >  #if !defined(CONFIG_DEBUG_PAGEALLOC) && !defined(CONFIG_KMEMCHECK)
> >  	/*
> >  	 * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
> >@@ -173,6 +162,14 @@ static void __init probe_page_size_mask(void)
> >  		cr4_set_bits_and_update_boot(X86_CR4_PGE);
> >  		__supported_pte_mask |= _PAGE_GLOBAL;
> >  	}
> >+
> >+	/* Enable 1 GB linear kernel mappings if available: */
> >+	if (direct_gbpages && cpu_has_gbpages) {
> >+		printk(KERN_INFO "Using GB pages for direct mapping\n");
> 
> pr_info()?

Yeah - probably in a separate patch, as there's three other KERN_ 
users in arch/x86/mm/init.c.

Thanks,

	Ingo
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