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
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
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.
Include "vmalloc" or "linear" in the kernel log message.
Link: http://lkml.kernel.org/r/20190605144814.29319-1-npiggin@xxxxxxxxx
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
--- a/mm/page_alloc.c~mm-large-system-hash-use-vmalloc-for-size-max_order-when-hashdist
+++ a/mm/page_alloc.c
@@ -7982,6 +7982,7 @@ void *__init alloc_large_system_hash(con
unsigned long log2qty, size;
void *table = NULL;
gfp_t gfp_flags;
+ bool virt;
/* allow the kernel cmdline to have a say */
if (!numentries) {
@@ -8038,6 +8039,7 @@ void *__init alloc_large_system_hash(con
gfp_flags = (flags & HASH_ZERO) ? GFP_ATOMIC | __GFP_ZERO : GFP_ATOMIC;
do {
+ virt = false;
size = bucketsize << log2qty;
if (flags & HASH_EARLY) {
if (flags & HASH_ZERO)
@@ -8045,26 +8047,26 @@ 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);
+ virt = true;
} else {
/*
* If bucketsize is not a power-of-two, we may free
* 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);
if (!table)
panic("Failed to allocate %s hash table\n", tablename);
- pr_info("%s hash table entries: %ld (order: %d, %lu bytes)\n",
- tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size);
+ pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n",
+ tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size,
+ virt ? "vmalloc" : "linear");
if (_hash_shift)
*_hash_shift = 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-clear-hashdist-when-only-one-node-with-memory-is-booted.patch
