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Commit 12031a62 authored by Yinghai Lu's avatar Yinghai Lu Committed by Thomas Gleixner
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x86: mtrr cleanup for converting continuous to discrete - auto detect v4 



Loop through mtrr chunk_size and gran_size from 1M to 2G to find out
the optimal value so user does not need to add mtrr_chunk_size and
mtrr_gran_size to the kernel command line.

If optimal value is not found, print out all list to help select less
optimal value.

Add mtrr_spare_reg_nr= so user could set 2 instead of 1, if the card
need more entries.

v2: find the one with more spare entries
v3: fix hole_basek offset
v4: tight the compare between range and range_new
    loop stop with 4g

Signed-off-by: default avatarYinghai Lu <yhlu.kernel@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Gabriel C <nix.or.die@googlemail.com>
Cc: Mika Fischer <mika.fischer@zoopnet.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent f5098d62

Documentation/kernel-parameters.txt

+11 −2
Original line number Diff line number Diff line
@@ -610,8 +610,17 @@ and is between 256 and 4096 characters. It is defined in the file 
			that could hold holes aka. UC entries.



	mtrr_gran_size=nn[KMG] [X86]

			used for mtrr cleanup. It is granity of mtrr block.

			Big value could prevent small alignment use up MTRRs.

			Used for mtrr cleanup. It is granularity of mtrr block.

			Default is 1.

			Large value could prevent small alignment from

			using up MTRRs.



	mtrr_spare_reg_nr=n [X86]

			Format: <integer>

			Range: 0,7 : spare reg number

			Default : 1

			Used for mtrr cleanup. It is spare mtrr entries number.

			Set to 2 or more if your graphical card needs more.



	disable_mtrr_trim [X86, Intel and AMD only]

			By default the kernel will trim any uncacheable

arch/x86/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -1117,6 +1117,15 @@ config MTRR_SANITIZER_ENABLE_DEFAULT 
	help

	  Enable mtrr cleanup default value



config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT

	int "MTRR cleanup spare reg num (0-7)"

	range 0 7

	default "1"

	depends on MTRR_SANITIZER

	help

	  mtrr cleanup spare entries default, it can be changed via

	  mtrr_spare_reg_nr=



config X86_PAT

	bool

	prompt "x86 PAT support"

arch/x86/kernel/cpu/mtrr/main.c

+464 −146

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