linux-kernel - Re: [PATCH] xen/balloon: Mark unallocated host memory as UNUSABLE

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Message-ID: <a8495745-b56a-83ff-993f-a745c8edf2c0@oracle.com>
Date:   Fri, 15 Dec 2017 09:24:50 -0500
From:   Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:     Juergen Gross <jgross@...e.com>, xen-devel@...ts.xen.org,
        linux-kernel@...r.kernel.org
Cc:     helgaas@...nel.org, christian.koenig@....com
Subject: Re: [PATCH] xen/balloon: Mark unallocated host memory as UNUSABLE


>> +
>> +	hostmem_resource->start = max_addr;
>> +	hostmem_resource->end = entry->addr + entry->size;
>> +	for (; i < memmap.nr_entries; i++) {
>> +		entry = &xen_e820_table->entries[i];
>> +		if (entry->type == E820_TYPE_RAM)
> Shouldn't that be != ?

No, the idea here is to populate hostmem_resource with ranges already
taken by things other than RAM, leaving memory regions as available for
the balloon hotplug. This will allow us to use allocate_resource(),
which searches for a free range, in the balloon driver.


>
>> +			continue;
>> +
>> +		res = kzalloc(sizeof(*res), GFP_KERNEL);
>> +		if (!res) {
>> +			pr_warn("%s: Out of memory\n", __func__);
> Don't print error message in case of allocation failures.

Right, In fact checkpatch also suggested that I drop it. And I forgot.


-boris