The patch titled
Subject: mm/large system hash: use vmalloc for size > MAX_ORDER when !hashdist
has been added to the -mm tree. Its filename is
mm-large-system-hash-use-vmalloc-for-size-max_order-when-hashdist.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-large-system-hash-use-vmalloc-for-size-max_order-when-hashdist.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-large-system-hash-use-vmalloc-for-size-max_order-when-hashdist.patch
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------------------------------------------------------
From: Nicholas Piggin <npiggin@xxxxxxxxx>
Subject: mm/large system hash: use vmalloc for size > MAX_ORDER when !hashdist
The kernel currently clamps large system hashes to MAX_ORDER when hashdist
is not set, which is rather arbitrary.
vmalloc space is limited on 32-bit machines, but this shouldn't result in
much more used because of small physical memory limiting system hash
sizes.
Link: http://lkml.kernel.org/r/20190528120453.27374-1-npiggin@xxxxxxxxx
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Toshi Kani <toshi.kani@xxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Uladzislau Rezki <urezki@xxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
--- a/mm/page_alloc.c~mm-large-system-hash-use-vmalloc-for-size-max_order-when-hashdist
+++ a/mm/page_alloc.c
@@ -8029,7 +8029,7 @@ void *__init alloc_large_system_hash(con
else
table = memblock_alloc_raw(size,
SMP_CACHE_BYTES);
- } else if (hashdist) {
+ } else if (get_order(size) >= MAX_ORDER || hashdist) {
table = __vmalloc(size, gfp_flags, PAGE_KERNEL);
} else {
/*
@@ -8037,10 +8037,8 @@ void *__init alloc_large_system_hash(con
* some pages at the end of hash table which
* alloc_pages_exact() automatically does
*/
- if (get_order(size) < MAX_ORDER) {
- table = alloc_pages_exact(size, gfp_flags);
- kmemleak_alloc(table, size, 1, gfp_flags);
- }
+ table = alloc_pages_exact(size, gfp_flags);
+ kmemleak_alloc(table, size, 1, gfp_flags);
}
} while (!table && size > PAGE_SIZE && --log2qty);
_
Patches currently in -mm which might be from npiggin@xxxxxxxxx are
mm-large-system-hash-use-vmalloc-for-size-max_order-when-hashdist.patch
mm-large-system-hash-avoid-vmap-for-non-numa-machines-when-hashdist.patch
mm-move-ioremap-page-table-mapping-function-to-mm.patch
mm-vmalloc-hugepage-vmalloc-mappings.patch
