| Message ID | 20241030130308.1066299-4-mcanal@igalia.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: add more kernel parameters to control mTHP | expand |
On 30.10.24 13:58, Maíra Canal 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 hugepages, the user > can take advantage of mTHP before it's been configured through sysfs. > > Signed-off-by: Maíra Canal <mcanal@igalia.com> > --- > .../admin-guide/kernel-parameters.txt | 10 ++ > Documentation/admin-guide/mm/transhuge.rst | 17 +++ > mm/shmem.c | 109 +++++++++++++++++- > 3 files changed, 135 insertions(+), 1 deletion(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index acabb04d0dd4..b48d744d99b0 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. > > + thp_shmem= [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. > + > 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 dfcc88ec6e34..c2299fa0b345 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 > @@ -5027,7 +5028,8 @@ 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; > > @@ -5180,6 +5182,26 @@ 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; > +} Hm, mostly copy and paste. You could reuse existing get_order_from_str() simply by passing in the supported orders and moving error reporting to the caller. static inline int get_order_from_str(const char *size_str, int valid_orders) { ... if (!is_power_of_2(size)) return -EINVAL; order = get_order(size); if (BIT(order) & ~valid_orders) return -EINVAL; return order; } > + > static int __init setup_transparent_hugepage_shmem(char *str) > { > int huge; > @@ -5195,6 +5217,91 @@ 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; > + strscpy(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; > + } > + } > + } Similarly, copy-paste. But not that easy to abstract :) So maybe we'll have to keep that as is for now.
Hi David, On 31/10/24 09:37, David Hildenbrand wrote: > On 30.10.24 13:58, Maíra Canal 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 hugepages, the user >> can take advantage of mTHP before it's been configured through sysfs. >> >> Signed-off-by: Maíra Canal <mcanal@igalia.com> >> --- >> .../admin-guide/kernel-parameters.txt | 10 ++ >> Documentation/admin-guide/mm/transhuge.rst | 17 +++ >> mm/shmem.c | 109 +++++++++++++++++- >> 3 files changed, 135 insertions(+), 1 deletion(-) >> [...] >> diff --git a/mm/shmem.c b/mm/shmem.c >> index dfcc88ec6e34..c2299fa0b345 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 >> @@ -5027,7 +5028,8 @@ 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; >> @@ -5180,6 +5182,26 @@ 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; >> +} > > Hm, mostly copy and paste. You could reuse existing get_order_from_str() > simply by passing in the supported orders and moving error reporting to > the caller. > Can I use functions from mm/huge_memory.c here? > static inline int get_order_from_str(const char *size_str, > int valid_orders) > { > ... > if (!is_power_of_2(size)) > return -EINVAL; > order = get_order(size); > if (BIT(order) & ~valid_orders) > return -EINVAL; > return order; > } > >> + >> static int __init setup_transparent_hugepage_shmem(char *str) >> { >> int huge; >> @@ -5195,6 +5217,91 @@ 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; >> + strscpy(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; >> + } >> + } >> + } > > > Similarly, copy-paste. But not that easy to abstract :) So maybe we'll > have to keep that as is for now. On v2 [1], I abstracted to reduce copy and paste, but me and Barry agreed that adding this sort of header to linux/huge_mm.h was weird. [1] https://lore.kernel.org/linux-mm/20241029002324.1062723-4-mcanal@igalia.com/ Best Regards, - Maíra > >
On 31.10.24 13:51, Maíra Canal wrote: > Hi David, > > On 31/10/24 09:37, David Hildenbrand wrote: >> On 30.10.24 13:58, Maíra Canal 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 hugepages, the user >>> can take advantage of mTHP before it's been configured through sysfs. >>> >>> Signed-off-by: Maíra Canal <mcanal@igalia.com> >>> --- >>> .../admin-guide/kernel-parameters.txt | 10 ++ >>> Documentation/admin-guide/mm/transhuge.rst | 17 +++ >>> mm/shmem.c | 109 +++++++++++++++++- >>> 3 files changed, 135 insertions(+), 1 deletion(-) >>> > > [...] > >>> diff --git a/mm/shmem.c b/mm/shmem.c >>> index dfcc88ec6e34..c2299fa0b345 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 >>> @@ -5027,7 +5028,8 @@ 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; >>> @@ -5180,6 +5182,26 @@ 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; >>> +} >> >> Hm, mostly copy and paste. You could reuse existing get_order_from_str() >> simply by passing in the supported orders and moving error reporting to >> the caller. >> > > Can I use functions from mm/huge_memory.c here? Yes, that's the idea.
Hi David, On 31/10/24 09:57, David Hildenbrand wrote: > On 31.10.24 13:51, Maíra Canal wrote: >> Hi David, >> >> On 31/10/24 09:37, David Hildenbrand wrote: >>> On 30.10.24 13:58, Maíra Canal 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 hugepages, the user >>>> can take advantage of mTHP before it's been configured through sysfs. >>>> >>>> Signed-off-by: Maíra Canal <mcanal@igalia.com> >>>> --- >>>> .../admin-guide/kernel-parameters.txt | 10 ++ >>>> Documentation/admin-guide/mm/transhuge.rst | 17 +++ >>>> mm/shmem.c | 109 +++++++++++++ >>>> ++++- >>>> 3 files changed, 135 insertions(+), 1 deletion(-) >>>> >> >> [...] >> >>>> diff --git a/mm/shmem.c b/mm/shmem.c >>>> index dfcc88ec6e34..c2299fa0b345 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 >>>> @@ -5027,7 +5028,8 @@ 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; >>>> @@ -5180,6 +5182,26 @@ 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; >>>> +} >>> >>> Hm, mostly copy and paste. You could reuse existing get_order_from_str() >>> simply by passing in the supported orders and moving error reporting to >>> the caller. >>> >> >> Can I use functions from mm/huge_memory.c here? > > Yes, that's the idea. > Unfortunately, it isn't possible without adding the function to a header. I deleted `get_order_from_str()` from mm/shmem.c just to test it: mm/shmem.c:5230:13: error: call to undeclared function 'get_order_from_str'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 5230 | start = get_order_from_str(start_size); | ^ mm/shmem.c:5233:19: error: call to undeclared function 'get_order_from_str'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 5233 | start = end = get_order_from_str(subtoken); | ^ 2 errors generated. make[3]: *** [scripts/Makefile.build:229: mm/shmem.o] Error 1 make[2]: *** [scripts/Makefile.build:478: mm] Error 2 make[2]: *** Waiting for unfinished jobs.... Please, check the discussion I had with Barry about the pros and cons of copy and paste and code refactor [1][2]. We ended up deciding to duplicate the code. [1] https://lore.kernel.org/linux-mm/CAGsJ_4wJ2xoNRLMNkmLL3x1t2YiqQJ1=saXa+HNxRUbSNivRCw@mail.gmail.com/ [2] https://lore.kernel.org/linux-mm/CAGsJ_4yp89one_hoB_87poU2wrpJh_0NVicRKW538eE6yo1kZw@mail.gmail.com/ Best Regards, - Maíra
On 31.10.24 14:24, Maíra Canal wrote: > Hi David, > > On 31/10/24 09:57, David Hildenbrand wrote: >> On 31.10.24 13:51, Maíra Canal wrote: >>> Hi David, >>> >>> On 31/10/24 09:37, David Hildenbrand wrote: >>>> On 30.10.24 13:58, Maíra Canal 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 hugepages, the user >>>>> can take advantage of mTHP before it's been configured through sysfs. >>>>> >>>>> Signed-off-by: Maíra Canal <mcanal@igalia.com> >>>>> --- >>>>> .../admin-guide/kernel-parameters.txt | 10 ++ >>>>> Documentation/admin-guide/mm/transhuge.rst | 17 +++ >>>>> mm/shmem.c | 109 +++++++++++++ >>>>> ++++- >>>>> 3 files changed, 135 insertions(+), 1 deletion(-) >>>>> >>> >>> [...] >>> >>>>> diff --git a/mm/shmem.c b/mm/shmem.c >>>>> index dfcc88ec6e34..c2299fa0b345 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 >>>>> @@ -5027,7 +5028,8 @@ 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; >>>>> @@ -5180,6 +5182,26 @@ 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; >>>>> +} >>>> >>>> Hm, mostly copy and paste. You could reuse existing get_order_from_str() >>>> simply by passing in the supported orders and moving error reporting to >>>> the caller. >>>> >>> >>> Can I use functions from mm/huge_memory.c here? >> >> Yes, that's the idea. >> > > Unfortunately, it isn't possible without adding the function to a > header. Well ... sure, what's the problem with that?
On 31/10/24 10:33, David Hildenbrand wrote: > On 31.10.24 14:24, Maíra Canal wrote: >> Hi David, >> >> On 31/10/24 09:57, David Hildenbrand wrote: >>> On 31.10.24 13:51, Maíra Canal wrote: >>>> Hi David, >>>> >>>> On 31/10/24 09:37, David Hildenbrand wrote: >>>>> On 30.10.24 13:58, Maíra Canal 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 hugepages, the >>>>>> user >>>>>> can take advantage of mTHP before it's been configured through sysfs. >>>>>> >>>>>> Signed-off-by: Maíra Canal <mcanal@igalia.com> >>>>>> --- >>>>>> .../admin-guide/kernel-parameters.txt | 10 ++ >>>>>> Documentation/admin-guide/mm/transhuge.rst | 17 +++ >>>>>> mm/shmem.c | 109 +++++++++++++ >>>>>> ++++- >>>>>> 3 files changed, 135 insertions(+), 1 deletion(-) >>>>>> >>>> >>>> [...] >>>> >>>>>> diff --git a/mm/shmem.c b/mm/shmem.c >>>>>> index dfcc88ec6e34..c2299fa0b345 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 >>>>>> @@ -5027,7 +5028,8 @@ 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; >>>>>> @@ -5180,6 +5182,26 @@ 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; >>>>>> +} >>>>> >>>>> Hm, mostly copy and paste. You could reuse existing >>>>> get_order_from_str() >>>>> simply by passing in the supported orders and moving error >>>>> reporting to >>>>> the caller. >>>>> >>>> >>>> Can I use functions from mm/huge_memory.c here? >>> >>> Yes, that's the idea. >>> >> >> Unfortunately, it isn't possible without adding the function to a >> header. > > Well ... sure, what's the problem with that? David & Barry, how do you feel about adding `get_order_from_str()` to lib/cmdline.c? Best Regards, - Maíra >
On Fri, Nov 1, 2024 at 3:20 AM Maíra Canal <mcanal@igalia.com> wrote: > > On 31/10/24 10:33, David Hildenbrand wrote: > > On 31.10.24 14:24, Maíra Canal wrote: > >> Hi David, > >> > >> On 31/10/24 09:57, David Hildenbrand wrote: > >>> On 31.10.24 13:51, Maíra Canal wrote: > >>>> Hi David, > >>>> > >>>> On 31/10/24 09:37, David Hildenbrand wrote: > >>>>> On 30.10.24 13:58, Maíra Canal 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 hugepages, the > >>>>>> user > >>>>>> can take advantage of mTHP before it's been configured through sysfs. > >>>>>> > >>>>>> Signed-off-by: Maíra Canal <mcanal@igalia.com> > >>>>>> --- > >>>>>> .../admin-guide/kernel-parameters.txt | 10 ++ > >>>>>> Documentation/admin-guide/mm/transhuge.rst | 17 +++ > >>>>>> mm/shmem.c | 109 +++++++++++++ > >>>>>> ++++- > >>>>>> 3 files changed, 135 insertions(+), 1 deletion(-) > >>>>>> > >>>> > >>>> [...] > >>>> > >>>>>> diff --git a/mm/shmem.c b/mm/shmem.c > >>>>>> index dfcc88ec6e34..c2299fa0b345 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 > >>>>>> @@ -5027,7 +5028,8 @@ 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; > >>>>>> @@ -5180,6 +5182,26 @@ 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; > >>>>>> +} > >>>>> > >>>>> Hm, mostly copy and paste. You could reuse existing > >>>>> get_order_from_str() > >>>>> simply by passing in the supported orders and moving error > >>>>> reporting to > >>>>> the caller. > >>>>> > >>>> > >>>> Can I use functions from mm/huge_memory.c here? > >>> > >>> Yes, that's the idea. > >>> > >> > >> Unfortunately, it isn't possible without adding the function to a > >> header. > > > > Well ... sure, what's the problem with that? > > David & Barry, how do you feel about adding `get_order_from_str()` to > lib/cmdline.c? I'd vote to leave it as is. If, at some point, the controls for shared memory and anonymous memory are moved to a file, that would be the right time to call the same get_order_from_str() for both. This is too trivial to warrant being an exposed API in huge_memory.h or cmdline. > > Best Regards, > - Maíra > Thanks Barry
On 31.10.24 22:12, Barry Song wrote: > On Fri, Nov 1, 2024 at 3:20 AM Maíra Canal <mcanal@igalia.com> wrote: >> >> On 31/10/24 10:33, David Hildenbrand wrote: >>> On 31.10.24 14:24, Maíra Canal wrote: >>>> Hi David, >>>> >>>> On 31/10/24 09:57, David Hildenbrand wrote: >>>>> On 31.10.24 13:51, Maíra Canal wrote: >>>>>> Hi David, >>>>>> >>>>>> On 31/10/24 09:37, David Hildenbrand wrote: >>>>>>> On 30.10.24 13:58, Maíra Canal 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 hugepages, the >>>>>>>> user >>>>>>>> can take advantage of mTHP before it's been configured through sysfs. >>>>>>>> >>>>>>>> Signed-off-by: Maíra Canal <mcanal@igalia.com> >>>>>>>> --- >>>>>>>> .../admin-guide/kernel-parameters.txt | 10 ++ >>>>>>>> Documentation/admin-guide/mm/transhuge.rst | 17 +++ >>>>>>>> mm/shmem.c | 109 +++++++++++++ >>>>>>>> ++++- >>>>>>>> 3 files changed, 135 insertions(+), 1 deletion(-) >>>>>>>> >>>>>> >>>>>> [...] >>>>>> >>>>>>>> diff --git a/mm/shmem.c b/mm/shmem.c >>>>>>>> index dfcc88ec6e34..c2299fa0b345 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 >>>>>>>> @@ -5027,7 +5028,8 @@ 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; >>>>>>>> @@ -5180,6 +5182,26 @@ 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; >>>>>>>> +} >>>>>>> >>>>>>> Hm, mostly copy and paste. You could reuse existing >>>>>>> get_order_from_str() >>>>>>> simply by passing in the supported orders and moving error >>>>>>> reporting to >>>>>>> the caller. >>>>>>> >>>>>> >>>>>> Can I use functions from mm/huge_memory.c here? >>>>> >>>>> Yes, that's the idea. >>>>> >>>> >>>> Unfortunately, it isn't possible without adding the function to a >>>> header. >>> >>> Well ... sure, what's the problem with that? >> >> David & Barry, how do you feel about adding `get_order_from_str()` to >> lib/cmdline.c? > > I'd vote to leave it as is. If, at some point, the controls for shared memory > and anonymous memory are moved to a file, that would be the right time > to call the same get_order_from_str() for both. > > This is too trivial to warrant being an exposed API in huge_memory.h > or cmdline. I ... don't quite agree. cmdline.c is probably a bit excessive and I wouldn't suggest that at this point. This seems like a reasonable helper function to have as inline in mm/internal.h. ... unless I am missing something important and the obvious code duplication is warranted.
On Fri, Nov 1, 2024 at 10:39 AM David Hildenbrand <david@redhat.com> wrote: > > On 31.10.24 22:12, Barry Song wrote: > > On Fri, Nov 1, 2024 at 3:20 AM Maíra Canal <mcanal@igalia.com> wrote: > >> > >> On 31/10/24 10:33, David Hildenbrand wrote: > >>> On 31.10.24 14:24, Maíra Canal wrote: > >>>> Hi David, > >>>> > >>>> On 31/10/24 09:57, David Hildenbrand wrote: > >>>>> On 31.10.24 13:51, Maíra Canal wrote: > >>>>>> Hi David, > >>>>>> > >>>>>> On 31/10/24 09:37, David Hildenbrand wrote: > >>>>>>> On 30.10.24 13:58, Maíra Canal 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 hugepages, the > >>>>>>>> user > >>>>>>>> can take advantage of mTHP before it's been configured through sysfs. > >>>>>>>> > >>>>>>>> Signed-off-by: Maíra Canal <mcanal@igalia.com> > >>>>>>>> --- > >>>>>>>> .../admin-guide/kernel-parameters.txt | 10 ++ > >>>>>>>> Documentation/admin-guide/mm/transhuge.rst | 17 +++ > >>>>>>>> mm/shmem.c | 109 +++++++++++++ > >>>>>>>> ++++- > >>>>>>>> 3 files changed, 135 insertions(+), 1 deletion(-) > >>>>>>>> > >>>>>> > >>>>>> [...] > >>>>>> > >>>>>>>> diff --git a/mm/shmem.c b/mm/shmem.c > >>>>>>>> index dfcc88ec6e34..c2299fa0b345 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 > >>>>>>>> @@ -5027,7 +5028,8 @@ 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; > >>>>>>>> @@ -5180,6 +5182,26 @@ 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; > >>>>>>>> +} > >>>>>>> > >>>>>>> Hm, mostly copy and paste. You could reuse existing > >>>>>>> get_order_from_str() > >>>>>>> simply by passing in the supported orders and moving error > >>>>>>> reporting to > >>>>>>> the caller. > >>>>>>> > >>>>>> > >>>>>> Can I use functions from mm/huge_memory.c here? > >>>>> > >>>>> Yes, that's the idea. > >>>>> > >>>> > >>>> Unfortunately, it isn't possible without adding the function to a > >>>> header. > >>> > >>> Well ... sure, what's the problem with that? > >> > >> David & Barry, how do you feel about adding `get_order_from_str()` to > >> lib/cmdline.c? > > > > I'd vote to leave it as is. If, at some point, the controls for shared memory > > and anonymous memory are moved to a file, that would be the right time > > to call the same get_order_from_str() for both. > > > This is too trivial to warrant being an exposed API in huge_memory.h > > or cmdline. > > I ... don't quite agree. cmdline.c is probably a bit excessive and I > wouldn't suggest that at this point. > > This seems like a reasonable helper function to have as inline in > mm/internal.h. For get_order_from_str() specifically, I agree that it's fine to keep it in internal.h, as it could be considered a general need. However, anything larger than that in parse bootcmd seems too trivial and not general enough to qualify as an API. > > ... unless I am missing something important and the obvious code > duplication is warranted. > > -- > Cheers, > > David / dhildenb > Thanks barry
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index acabb04d0dd4..b48d744d99b0 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. + thp_shmem= [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. + 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 dfcc88ec6e34..c2299fa0b345 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 @@ -5027,7 +5028,8 @@ 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; @@ -5180,6 +5182,26 @@ 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; @@ -5195,6 +5217,91 @@ 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; + strscpy(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; +} +__setup("thp_shmem=", setup_thp_shmem); + #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #else /* !CONFIG_SHMEM */
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 hugepages, the user can take advantage of mTHP before it's been configured through sysfs. Signed-off-by: Maíra Canal <mcanal@igalia.com> --- .../admin-guide/kernel-parameters.txt | 10 ++ Documentation/admin-guide/mm/transhuge.rst | 17 +++ mm/shmem.c | 109 +++++++++++++++++- 3 files changed, 135 insertions(+), 1 deletion(-)