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x86-64: fall back to regular page vmemmap on allocation failure

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Memory hotplug can happen on a machine under load, memory shortness
and fragmentation, so huge page allocations for the vmemmap are not
guaranteed to succeed.

Try to fall back to regular pages before failing the hotplug event
completely.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Bernhard Schmidt <Bernhard.Schmidt@lrz.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Johannes Weiner 2013-04-29 15:07:56 -07:00 committed by Linus Torvalds
parent e8216da5c7
commit 8e2cdbcb86
1 changed files with 24 additions and 18 deletions
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42
arch/x86/mm/init_64.c
View file

@ -1303,31 +1303,37 @@ static int __meminit vmemmap_populate_hugepages(unsigned long start,
pmd = pmd_offset(pud, addr); pmd = pmd_offset(pud, addr);
if (pmd_none(*pmd)) { if (pmd_none(*pmd)) {
pte_t entry;
void *p; void *p;
p = vmemmap_alloc_block_buf(PMD_SIZE, node); p = vmemmap_alloc_block_buf(PMD_SIZE, node);
if (!p) if (p) {
return -ENOMEM; pte_t entry;
entry = pfn_pte(__pa(p) >> PAGE_SHIFT, entry = pfn_pte(__pa(p) >> PAGE_SHIFT,
PAGE_KERNEL_LARGE); PAGE_KERNEL_LARGE);
set_pmd(pmd, __pmd(pte_val(entry))); set_pmd(pmd, __pmd(pte_val(entry)));
/* check to see if we have contiguous blocks */ /* check to see if we have contiguous blocks */
if (p_end != p || node_start != node) { if (p_end != p || node_start != node) {
if (p_start) if (p_start)
printk(KERN_DEBUG " [%lx-%lx] PMD -> [%p-%p] on node %d\n", printk(KERN_DEBUG " [%lx-%lx] PMD -> [%p-%p] on node %d\n",
addr_start, addr_end-1, p_start, p_end-1, node_start); addr_start, addr_end-1, p_start, p_end-1, node_start);
addr_start = addr; addr_start = addr;
node_start = node; node_start = node;
p_start = p; p_start = p;
}
addr_end = addr + PMD_SIZE;
p_end = p + PMD_SIZE;
continue;
} }
} else if (pmd_large(*pmd)) {
addr_end = addr + PMD_SIZE;
p_end = p + PMD_SIZE;
} else
vmemmap_verify((pte_t *)pmd, node, addr, next); vmemmap_verify((pte_t *)pmd, node, addr, next);
continue;
}
pr_warn_once("vmemmap: falling back to regular page backing\n");
if (vmemmap_populate_basepages(addr, next, node))
return -ENOMEM;
} }
return 0; return 0;
} }