Hi Maíra, On Mon, Oct 28, 2024 at 5:54 AM Barry Song <21cnbao@xxxxxxxxx> wrote: > > 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"? +1 IHMO, it seems like 'thp_shmem' would be better, as it appears to fit well with 'thp_anon' in naming style ;) Thanks, Lance > > > + > > 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