On 08/08/2024 11:16, Ryan Roberts wrote: > 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>[KMG]:<value> > > 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. > > Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx> > --- > > Hi All, > > I've split this off from my RFC at [1] because Barry highlighted that he would > benefit from it immediately [2]. There are no changes vs the version in that > series. Forgot to link the references, oops: [1] https://lore.kernel.org/linux-mm/20240717071257.4141363-1-ryan.roberts@xxxxxxx/ [2] https://lore.kernel.org/linux-mm/CAGsJ_4wiZRP9siEk9WpAYRjj-gehxptGY9XWC8k3N4QHBppAhQ@xxxxxxxxxxxxxx/ > > It applies against today's mm-unstable (275d686abcb59). (although I had to fix a > minor build bug in stackdepot.c due to MIN() not being defined in this tree). > > Thanks, > Ryan > > > .../admin-guide/kernel-parameters.txt | 8 +++ > Documentation/admin-guide/mm/transhuge.rst | 26 +++++++-- > mm/huge_memory.c | 55 ++++++++++++++++++- > 3 files changed, 82 insertions(+), 7 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index bcdee8984e1f0..5c79b58c108ec 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -6631,6 +6631,14 @@ > <deci-seconds>: poll all this frequency > 0: no polling (default) > > + thp_anon= [KNL] > + Format: <size>[KMG]:always|madvise|never|inherit > + Can be used to 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. > diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst > index 24eec1c03ad88..f63b0717366c6 100644 > --- a/Documentation/admin-guide/mm/transhuge.rst > +++ b/Documentation/admin-guide/mm/transhuge.rst > @@ -284,13 +284,27 @@ 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>[KMG]:<state>``, where ``<size>`` is the THP size > +and ``<state>`` is one of ``always``, ``madvise``, ``never`` or > +``inherit``. > + > +For example, the following will set 64K THP to ``always``:: > + > + thp_anon=64K:always > + > +``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``. > > Hugepages in tmpfs/shmem > ======================== > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 0c3075ee00012..c2c0da1eb94e6 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -82,6 +82,7 @@ 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; > > unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma, > unsigned long vm_flags, > @@ -672,7 +673,10 @@ 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); > + anon_orders_configured = true; > + } > > *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); > if (unlikely(!*hugepage_kobj)) { > @@ -857,6 +861,55 @@ static int __init setup_transparent_hugepage(char *str) > } > __setup("transparent_hugepage=", setup_transparent_hugepage); > > +static int __init setup_thp_anon(char *str) > +{ > + unsigned long size; > + char *state; > + int order; > + int ret = 0; > + > + if (!str) > + goto out; > + > + size = (unsigned long)memparse(str, &state); > + order = ilog2(size >> PAGE_SHIFT); > + if (*state != ':' || !is_power_of_2(size) || size <= PAGE_SIZE || > + !(BIT(order) & THP_ORDERS_ALL_ANON)) > + goto out; > + > + state++; > + > + if (!strcmp(state, "always")) { > + clear_bit(order, &huge_anon_orders_inherit); > + clear_bit(order, &huge_anon_orders_madvise); > + set_bit(order, &huge_anon_orders_always); > + ret = 1; > + } else if (!strcmp(state, "inherit")) { > + clear_bit(order, &huge_anon_orders_always); > + clear_bit(order, &huge_anon_orders_madvise); > + set_bit(order, &huge_anon_orders_inherit); > + ret = 1; > + } else if (!strcmp(state, "madvise")) { > + clear_bit(order, &huge_anon_orders_always); > + clear_bit(order, &huge_anon_orders_inherit); > + set_bit(order, &huge_anon_orders_madvise); > + ret = 1; > + } else if (!strcmp(state, "never")) { > + clear_bit(order, &huge_anon_orders_always); > + clear_bit(order, &huge_anon_orders_inherit); > + clear_bit(order, &huge_anon_orders_madvise); > + ret = 1; > + } > + > + if (ret) > + anon_orders_configured = true; > +out: > + if (!ret) > + pr_warn("thp_anon=%s: cannot parse, ignored\n", str); > + return ret; > +} > +__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)) > -- > 2.43.0 >
