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s390/mm: avoid trimming to MAX_ORDER 

Trimming to MAX_ORDER was originally done in order to avoid to set
HOLES_IN_ZONE, which in turn would enable a quite expensive
pfn_valid() check. pfn_valid() however only checks if a struct page
exists for a given pfn.

With sparsemen vmemmap there are always struct pages, since memmaps
are allocated for whole sections. Therefore remove the HOLES_IN_ZONE
comment and the trimming.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2020-07-14 07:46:40 +02:00
parent a709423f7a
commit 3c5f2eb969
1 changed files with 0 additions and 8 deletions
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8
arch/s390/kernel/setup.c
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@ -1126,14 +1126,6 @@ void __init setup_arch(char **cmdline_p)
free_mem_detect_info();
remove_oldmem();
/*
* Make sure all chunks are MAX_ORDER aligned so we don't need the
* extra checks that HOLES_IN_ZONE would require.
*
* Is this still required?
*/
memblock_trim_memory(1UL << (MAX_ORDER - 1 + PAGE_SHIFT));
if (is_prot_virt_host())
setup_uv();
setup_memory_end();