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mm: override mTHP "enabled" defaults at kernel cmdline

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Add thp_anon= cmdline parameter to allow specifying the default enablement
of each supported anon THP size.  The parameter accepts the following
format and can be provided multiple times to configure each size:

thp_anon=<size>,<size>[KMG]:<value>;<size>-<size>[KMG]:<value>

An example:

thp_anon=16K-64K:always;128K,512K:inherit;256K:madvise;1M-2M:never

See Documentation/admin-guide/mm/transhuge.rst for more details.

Configuring the defaults at boot time is useful to allow early user space
to take advantage of mTHP before its been configured through sysfs.

[v-songbaohua@oppo.com: use get_oder() and check size is is_power_of_2]
  Link: https://lkml.kernel.org/r/20240814224635.43272-1-21cnbao@gmail.com
[ryan.roberts@arm.com: some minor cleanup according to David's comments]
  Link: https://lkml.kernel.org/r/20240820105244.62703-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240814020247.67297-1-21cnbao@gmail.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Co-developed-by: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Ryan Roberts 2024-08-14 14:02:47 +12:00 committed by Andrew Morton
parent ed4dfd9aa1
commit dd4d30d1cd
3 changed files with 136 additions and 7 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

9
Documentation/admin-guide/kernel-parameters.txt
View file

@ -6614,6 +6614,15 @@
<deci-seconds>: poll all this frequency
0: no polling (default)
thp_anon= [KNL]
Format: <size>,<size>[KMG]:<state>;<size>-<size>[KMG]:<state>
state is one of "always", "madvise", "never" or "inherit".
Control the default behavior of the system with respect
to anonymous transparent hugepages.
Can be used multiple times for multiple anon THP sizes.
See Documentation/admin-guide/mm/transhuge.rst for more
details.
threadirqs [KNL,EARLY]
Force threading of all interrupt handlers except those
marked explicitly IRQF_NO_THREAD.

36
Documentation/admin-guide/mm/transhuge.rst
View file

@ -284,13 +284,37 @@ that THP is shared. Exceeding the number would block the collapse::
A higher value may increase memory footprint for some workloads.
Boot parameter
==============
Boot parameters
===============
You can change the sysfs boot time defaults of Transparent Hugepage
Support by passing the parameter ``transparent_hugepage=always`` or
``transparent_hugepage=madvise`` or ``transparent_hugepage=never``
to the kernel command line.
You can change the sysfs boot time default for the top-level "enabled"
control by passing the parameter ``transparent_hugepage=always`` or
``transparent_hugepage=madvise`` or ``transparent_hugepage=never`` to the
kernel command line.
Alternatively, each supported anonymous THP size can be controlled by
passing ``thp_anon=<size>,<size>[KMG]:<state>;<size>-<size>[KMG]:<state>``,
where ``<size>`` is the THP size (must be a power of 2 of PAGE_SIZE and
supported anonymous THP) and ``<state>`` is one of ``always``, ``madvise``,
``never`` or ``inherit``.
For example, the following will set 16K, 32K, 64K THP to ``always``,
set 128K, 512K to ``inherit``, set 256K to ``madvise`` and 1M, 2M
to ``never``::
thp_anon=16K-64K:always;128K,512K:inherit;256K:madvise;1M-2M:never
``thp_anon=`` may be specified multiple times to configure all THP sizes as
required. If ``thp_anon=`` is specified at least once, any anon THP sizes
not explicitly configured on the command line are implicitly set to
``never``.
``transparent_hugepage`` setting only affects the global toggle. If
``thp_anon`` is not specified, PMD_ORDER THP will default to ``inherit``.
However, if a valid ``thp_anon`` setting is provided by the user, the
PMD_ORDER THP policy will be overridden. If the policy for PMD_ORDER
is not defined within a valid ``thp_anon``, its policy will default to
``never``.
Hugepages in tmpfs/shmem
========================

98
mm/huge_memory.c
View file

@ -81,6 +81,7 @@ unsigned long huge_zero_pfn __read_mostly = ~0UL;
unsigned long huge_anon_orders_always __read_mostly;
unsigned long huge_anon_orders_madvise __read_mostly;
unsigned long huge_anon_orders_inherit __read_mostly;
static bool anon_orders_configured __initdata;
unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
unsigned long vm_flags,
@ -649,7 +650,8 @@ static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj)
* disable all other sizes. powerpc's PMD_ORDER isn't a compile-time
* constant so we have to do this here.
*/
huge_anon_orders_inherit = BIT(PMD_ORDER);
if (!anon_orders_configured)
huge_anon_orders_inherit = BIT(PMD_ORDER);
*hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj);
if (unlikely(!*hugepage_kobj)) {
@ -834,6 +836,100 @@ static int __init setup_transparent_hugepage(char *str)
}
__setup("transparent_hugepage=", setup_transparent_hugepage);
static inline int get_order_from_str(const char *size_str)
{
unsigned long size;
char *endptr;
int order;
size = memparse(size_str, &endptr);
if (!is_power_of_2(size))
goto err;
order = get_order(size);
if (BIT(order) & ~THP_ORDERS_ALL_ANON)
goto err;
return order;
err:
pr_err("invalid size %s in thp_anon boot parameter\n", size_str);
return -EINVAL;
}
static char str_dup[PAGE_SIZE] __initdata;
static int __init setup_thp_anon(char *str)
{
char *token, *range, *policy, *subtoken;
unsigned long always, inherit, madvise;
char *start_size, *end_size;
int start, end, nr;
char *p;
if (!str || strlen(str) + 1 > PAGE_SIZE)
goto err;
strcpy(str_dup, str);
always = huge_anon_orders_always;
madvise = huge_anon_orders_madvise;
inherit = huge_anon_orders_inherit;
p = str_dup;
while ((token = strsep(&p, ";")) != NULL) {
range = strsep(&token, ":");
policy = token;
if (!policy)
goto err;
while ((subtoken = strsep(&range, ",")) != NULL) {
if (strchr(subtoken, '-')) {
start_size = strsep(&subtoken, "-");
end_size = subtoken;
start = get_order_from_str(start_size);
end = get_order_from_str(end_size);
} else {
start = end = get_order_from_str(subtoken);
}
if (start < 0 || end < 0 || start > end)
goto err;
nr = end - start + 1;
if (!strcmp(policy, "always")) {
bitmap_set(&always, start, nr);
bitmap_clear(&inherit, start, nr);
bitmap_clear(&madvise, start, nr);
} else if (!strcmp(policy, "madvise")) {
bitmap_set(&madvise, start, nr);
bitmap_clear(&inherit, start, nr);
bitmap_clear(&always, start, nr);
} else if (!strcmp(policy, "inherit")) {
bitmap_set(&inherit, start, nr);
bitmap_clear(&madvise, start, nr);
bitmap_clear(&always, start, nr);
} else if (!strcmp(policy, "never")) {
bitmap_clear(&inherit, start, nr);
bitmap_clear(&madvise, start, nr);
bitmap_clear(&always, start, nr);
} else {
pr_err("invalid policy %s in thp_anon boot parameter\n", policy);
goto err;
}
}
}
huge_anon_orders_always = always;
huge_anon_orders_madvise = madvise;
huge_anon_orders_inherit = inherit;
anon_orders_configured = true;
return 1;
err:
pr_warn("thp_anon=%s: error parsing string, ignoring setting\n", str);
return 0;
}
__setup("thp_anon=", setup_thp_anon);
pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
{
if (likely(vma->vm_flags & VM_WRITE))