linux-kernel - Re: [PATCH v2 4/5] mm: memory_hotplug: Add memory hotremove probe device

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Date:   Fri, 24 Nov 2017 18:35:11 +0800
From:   zhong jiang <zhongjiang@...wei.com>
To:     Andrea Reale <ar@...ux.vnet.ibm.com>
CC:     <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>,
        <m.bielski@...tualopensystems.com>, <arunks@....qualcomm.com>,
        <mark.rutland@....com>, <scott.branden@...adcom.com>,
        <will.deacon@....com>, <qiuxishi@...wei.com>,
        <catalin.marinas@....com>, <mhocko@...e.com>, <realean2@...ibm.com>
Subject: Re: [PATCH v2 4/5] mm: memory_hotplug: Add memory hotremove probe
 device

HI, Andrea

I don't see "memory_add_physaddr_to_nid" in arch/arm64.
Am I miss something?

Thnaks
zhongjiang

On 2017/11/23 19:14, Andrea Reale wrote:
> Adding a "remove" sysfs handle that can be used to trigger
> memory hotremove manually, exactly simmetrically with
> what happens with the "probe" device for hot-add.
>
> This is usueful for architecture that do not rely on
> ACPI for memory hot-remove.
>
> Signed-off-by: Andrea Reale <ar@...ux.vnet.ibm.com>
> Signed-off-by: Maciej Bielski <m.bielski@...tualopensystems.com>
> ---
>  drivers/base/memory.c | 34 +++++++++++++++++++++++++++++++++-
>  1 file changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index 1d60b58..8ccb67c 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -530,7 +530,36 @@ memory_probe_store(struct device *dev, struct device_attribute *attr,
>  }
>  
>  static DEVICE_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
> -#endif
> +
> +#ifdef CONFIG_MEMORY_HOTREMOVE
> +static ssize_t
> +memory_remove_store(struct device *dev,
> +		struct device_attribute *attr, const char *buf, size_t count)
> +{
> +	u64 phys_addr;
> +	int nid, ret;
> +	unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
> +
> +	ret = kstrtoull(buf, 0, &phys_addr);
> +	if (ret)
> +		return ret;
> +
> +	if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
> +		return -EINVAL;
> +
> +	nid = memory_add_physaddr_to_nid(phys_addr);
> +	ret = lock_device_hotplug_sysfs();
> +	if (ret)
> +		return ret;
> +
> +	remove_memory(nid, phys_addr,
> +			 MIN_MEMORY_BLOCK_SIZE * sections_per_block);
> +	unlock_device_hotplug();
> +	return count;
> +}
> +static DEVICE_ATTR(remove, S_IWUSR, NULL, memory_remove_store);
> +#endif /* CONFIG_MEMORY_HOTREMOVE */
> +#endif /* CONFIG_ARCH_MEMORY_PROBE */
>  
>  #ifdef CONFIG_MEMORY_FAILURE
>  /*
> @@ -790,6 +819,9 @@ bool is_memblock_offlined(struct memory_block *mem)
>  static struct attribute *memory_root_attrs[] = {
>  #ifdef CONFIG_ARCH_MEMORY_PROBE
>  	&dev_attr_probe.attr,
> +#ifdef CONFIG_MEMORY_HOTREMOVE
> +	&dev_attr_remove.attr,
> +#endif
>  #endif
>  
>  #ifdef CONFIG_MEMORY_FAILURE