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From: Mike Rapoport <rppt@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Borislav Petkov <bp@alien8.de>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Christopher Lameter <cl@linux.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Elena Reshetova <elena.reshetova@intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Idan Yaniv <idan.yaniv@ibm.com>,
	Ingo Molnar <mingo@redhat.com>,
	James Bottomley <jejb@linux.ibm.com>,
	"Kirill A. Shutemov" <kirill@shutemov.name>,
	Matthew Wilcox <willy@infradead.org>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Michael Kerrisk <mtk.manpages@gmail.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Tycho Andersen <tycho@tycho.ws>, Will Deacon <will@kernel.org>,
	linux-api@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-nvdimm@lists.01.org, linux-riscv@lists.infradead.org,
	x86@kernel.org
Subject: Re: [PATCH v2 7/7] mm: secretmem: add ability to reserve memory at boot
Date: Mon, 27 Jul 2020 20:11:02 +0300
Message-ID: <20200727171102.GA3655207@kernel.org> (raw)
In-Reply-To: <20200727162935.31714-8-rppt@kernel.org>

Oops, something went wrong with the rebase, this should have been
squashed into the previous patch...

On Mon, Jul 27, 2020 at 07:29:35PM +0300, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
> 
> Taking pages out from the direct map and bringing them back may create
> undesired fragmentation and usage of the smaller pages in the direct
> mapping of the physical memory.
> 
> This can be avoided if a significantly large area of the physical memory
> would be reserved for secretmem purposes at boot time.
> 
> Add ability to reserve physical memory for secretmem at boot time using
> "secretmem" kernel parameter and then use that reserved memory as a global
> pool for secret memory needs.
> 
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
>  Documentation/admin-guide/kernel-parameters.txt | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index fb95fad81c79..6f3c2f28160f 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4548,6 +4548,10 @@
>  			Format: integer between 0 and 10
>  			Default is 0.
>  
> +	secretmem=n[KMG]
> +			[KNL,BOOT] Reserve specified amount of memory to
> +			back mappings of secret memory.
> +
>  	skew_tick=	[KNL] Offset the periodic timer tick per cpu to mitigate
>  			xtime_lock contention on larger systems, and/or RCU lock
>  			contention on all systems with CONFIG_MAXSMP set.
> -- 
> 2.26.2
> 

-- 
Sincerely yours,
Mike.

      reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-27 16:29 [PATCH v2 0/7] mm: introduce memfd_secret system call to create "secret" memory areas Mike Rapoport
2020-07-27 16:29 ` [PATCH v2 1/7] mm: add definition of PMD_PAGE_ORDER Mike Rapoport
2020-07-27 16:29 ` [PATCH v2 2/7] mmap: make mlock_future_check() global Mike Rapoport
2020-07-27 16:29 ` [PATCH v2 3/7] mm: introduce memfd_secret system call to create "secret" memory areas Mike Rapoport
2020-07-30 16:22   ` Catalin Marinas
2020-07-30 20:44     ` Mike Rapoport
2020-07-31 14:10       ` Catalin Marinas
2020-07-31 14:29     ` Mark Rutland
2020-07-31 16:22       ` Catalin Marinas
2020-07-27 16:29 ` [PATCH v2 4/7] arch, mm: wire up memfd_secret system call were relevant Mike Rapoport
2020-07-27 17:25   ` Arnd Bergmann
2020-07-27 16:29 ` [PATCH v2 5/7] mm: secretmem: use PMD-size pages to amortize direct map fragmentation Mike Rapoport
2020-07-27 16:29 ` [PATCH v2 6/7] mm: secretmem: add ability to reserve memory at boot Mike Rapoport
2020-07-27 16:29 ` [PATCH v2 7/7] " Mike Rapoport
2020-07-27 17:11   ` Mike Rapoport [this message]

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