On Mon, Oct 28, 2024 at 6:58 AM Maíra Canal <mcanal@xxxxxxxxxx> wrote: > > Add the ``thp_shmem=`` kernel command line to allow specifying the > default policy of each supported shmem hugepage size. The kernel parameter > accepts the following format: > > thp_shmem=<size>[KMG],<size>[KMG]:<policy>;<size>[KMG]-<size>[KMG]:<policy> > > For example, > > thp_shmem=16K-64K:always;128K,512K:inherit;256K:advise;1M-2M:never;4M-8M:within_size > > By configuring the default policy of several shmem huge pages, the user > can take advantage of mTHP before it's been configured through sysfs. > > Signed-off-by: Maíra Canal <mcanal@xxxxxxxxxx> > --- > .../admin-guide/kernel-parameters.txt | 10 ++ > Documentation/admin-guide/mm/transhuge.rst | 17 +++ > mm/shmem.c | 109 +++++++++++++++++- > 3 files changed, 135 insertions(+), 1 deletion(-) > Hi Maíra, > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index acabb04d0dd4..595fa096e28b 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -6700,6 +6700,16 @@ > Force threading of all interrupt handlers except those > marked explicitly IRQF_NO_THREAD. > > + shmem_anon= [KNL] > + Format: <size>[KMG],<size>[KMG]:<policy>;<size>[KMG]-<size>[KMG]:<policy> > + Control the default policy of each hugepage size for the > + internal shmem mount. <policy> is one of policies available > + for the shmem mount ("always", "inherit", "never", "within_size", > + and "advise"). > + It can be used multiple times for multiple shmem THP sizes. > + See Documentation/admin-guide/mm/transhuge.rst for more > + details. I'm not sure this is the right name. How about "thp_shmem"? > + > topology= [S390,EARLY] > Format: {off | on} > Specify if the kernel should make use of the cpu > diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst > index 9b5b02c4d1ab..47e7fc30e22d 100644 > --- a/Documentation/admin-guide/mm/transhuge.rst > +++ b/Documentation/admin-guide/mm/transhuge.rst > @@ -332,6 +332,23 @@ allocation policy for the internal shmem mount by using the kernel parameter > seven valid policies for shmem (``always``, ``within_size``, ``advise``, > ``never``, ``deny``, and ``force``). > > +In the same manner as ``thp_anon`` controls each supported anonymous THP > +size, ``thp_shmem`` controls each supported shmem THP size. ``thp_shmem`` > +has the same format as ``thp_anon``, but also supports the policy > +``within_size``. > + > +``thp_shmem=`` may be specified multiple times to configure all THP sizes > +as required. If ``thp_shmem=`` is specified at least once, any shmem THP > +sizes not explicitly configured on the command line are implicitly set to > +``never``. > + > +``transparent_hugepage_shmem`` setting only affects the global toggle. If > +``thp_shmem`` is not specified, PMD_ORDER hugepage will default to > +``inherit``. However, if a valid ``thp_shmem`` setting is provided by the > +user, the PMD_ORDER hugepage policy will be overridden. If the policy for > +PMD_ORDER is not defined within a valid ``thp_shmem``, its policy will > +default to ``never``. > + > Hugepages in tmpfs/shmem > ======================== > > diff --git a/mm/shmem.c b/mm/shmem.c > index 24cdeafd8260..0a7a7d04f725 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -136,6 +136,7 @@ static unsigned long huge_shmem_orders_always __read_mostly; > static unsigned long huge_shmem_orders_madvise __read_mostly; > static unsigned long huge_shmem_orders_inherit __read_mostly; > static unsigned long huge_shmem_orders_within_size __read_mostly; > +static bool shmem_orders_configured __initdata; > #endif > > #ifdef CONFIG_TMPFS > @@ -5013,7 +5014,8 @@ void __init shmem_init(void) > * Default to setting PMD-sized THP to inherit the global setting and > * disable all other multi-size THPs. > */ > - huge_shmem_orders_inherit = BIT(HPAGE_PMD_ORDER); > + if (!shmem_orders_configured) > + huge_shmem_orders_inherit = BIT(HPAGE_PMD_ORDER); > #endif > return; > > @@ -5174,6 +5176,26 @@ struct kobj_attribute thpsize_shmem_enabled_attr = > > #if defined(CONFIG_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_FILE_DEFAULT) > + goto err; > + > + return order; > +err: > + pr_err("invalid size %s in thp_shmem boot parameter\n", size_str); > + return -EINVAL; > +} > + > static int __init setup_transparent_hugepage_shmem(char *str) > { > int huge, ret = 0; > @@ -5206,6 +5228,91 @@ static int __init setup_transparent_hugepage_shmem(char *str) > } > __setup("transparent_hugepage_shmem=", setup_transparent_hugepage_shmem); > > +static char str_dup[PAGE_SIZE] __initdata; > +static int __init setup_thp_shmem(char *str) > +{ > + char *token, *range, *policy, *subtoken; > + unsigned long always, inherit, madvise, within_size; > + 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_shmem_orders_always; > + inherit = huge_shmem_orders_inherit; > + madvise = huge_shmem_orders_madvise; > + within_size = huge_shmem_orders_within_size; > + 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); > + bitmap_clear(&within_size, start, nr); > + } else if (!strcmp(policy, "advise")) { > + bitmap_set(&madvise, start, nr); > + bitmap_clear(&inherit, start, nr); > + bitmap_clear(&always, start, nr); > + bitmap_clear(&within_size, start, nr); > + } else if (!strcmp(policy, "inherit")) { > + bitmap_set(&inherit, start, nr); > + bitmap_clear(&madvise, start, nr); > + bitmap_clear(&always, start, nr); > + bitmap_clear(&within_size, start, nr); > + } else if (!strcmp(policy, "within_size")) { > + bitmap_set(&within_size, start, nr); > + bitmap_clear(&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); > + bitmap_clear(&within_size, start, nr); > + } else { > + pr_err("invalid policy %s in thp_shmem boot parameter\n", policy); > + goto err; > + } > + } > + } > + > + huge_shmem_orders_always = always; > + huge_shmem_orders_madvise = madvise; > + huge_shmem_orders_inherit = inherit; > + huge_shmem_orders_within_size = within_size; > + shmem_orders_configured = true; > + return 1; > + > +err: > + pr_warn("thp_shmem=%s: error parsing string, ignoring setting\n", str); > + return 0; > +} Can we share source code with thp_anon since there's a lot of duplication? > +__setup("thp_shmem=", setup_thp_shmem); > + > #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ > > #else /* !CONFIG_SHMEM */ > -- > 2.46.2 > Thanks barry