From: Laura Abbott <labbott@redhat•com>
To: Mike Rapoport <rppt@kernel•org>,
Catalin Marinas <catalin.marinas@arm•com>,
Will Deacon <will@kernel•org>,
Mark Rutland <mark.rutland@arm•com>
Cc: linux-kernel@vger•kernel.org,
linux-arm-kernel@lists•infradead.org,
Mike Rapoport <rppt@linux•ibm.com>
Subject: Re: [PATCH] arm64: use generic free_initrd_mem()
Date: Mon, 16 Sep 2019 08:23:29 -0400 [thread overview]
Message-ID: <0ba20aa4-d2dd-2263-6b5f-16a5c8a39f67@redhat.com> (raw)
In-Reply-To: <1568618488-19055-1-git-send-email-rppt@kernel.org>
On 9/16/19 8:21 AM, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux•ibm.com>
>
> arm64 calls memblock_free() for the initrd area in its implementation of
> free_initrd_mem(), but this call has no actual effect that late in the boot
> process. By the time initrd is freed, all the reserved memory is managed by
> the page allocator and the memblock.reserved is unused, so there is no
> point to update it.
>
People like to use memblock for keeping track of memory even if it has no
actual effect. We made this change explicitly (see 05c58752f9dc ("arm64: To remove
initrd reserved area entry from memblock") That said, moving to the generic
APIs would be nice. Maybe we can find another place to update the accounting?
> Without the memblock_free() call the only difference between arm64 and the
> generic versions of free_initrd_mem() is the memory poisoning. Switching
> arm64 to the generic version will enable the poisoning.
>
> Signed-off-by: Mike Rapoport <rppt@linux•ibm.com>
> ---
>
> I've boot tested it on qemu and I've checked that kexec works.
>
> arch/arm64/mm/init.c | 8 --------
> 1 file changed, 8 deletions(-)
>
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index f3c7952..8ad2934 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -567,14 +567,6 @@ void free_initmem(void)
> unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin));
> }
>
> -#ifdef CONFIG_BLK_DEV_INITRD
> -void __init free_initrd_mem(unsigned long start, unsigned long end)
> -{
> - free_reserved_area((void *)start, (void *)end, 0, "initrd");
> - memblock_free(__virt_to_phys(start), end - start);
> -}
> -#endif
> -
> /*
> * Dump out memory limit information on panic.
> */
>
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next prev parent reply other threads:[~2019-09-16 12:23 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-16 7:21 [PATCH] arm64: use generic free_initrd_mem() Mike Rapoport
2019-09-16 12:23 ` Laura Abbott [this message]
2019-09-16 13:55 ` Mike Rapoport
2019-09-23 10:11 ` Anshuman Khandual
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