diff options
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 40 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/hugetlbpage.rst | 35 | ||||
| -rw-r--r-- | mm/hugetlb.c | 159 |
3 files changed, 190 insertions, 44 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 4379c6ac3265..f4d123b57c5b 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -834,12 +834,15 @@ See also Documentation/networking/decnet.txt. default_hugepagesz= - [same as hugepagesz=] The size of the default - HugeTLB page size. This is the size represented by - the legacy /proc/ hugepages APIs, used for SHM, and - default size when mounting hugetlbfs filesystems. - Defaults to the default architecture's huge page size - if not specified. + [HW] The size of the default HugeTLB page. This is + the size represented by the legacy /proc/ hugepages + APIs. In addition, this is the default hugetlb size + used for shmget(), mmap() and mounting hugetlbfs + filesystems. If not specified, defaults to the + architecture's default huge page size. Huge page + sizes are architecture dependent. See also + Documentation/admin-guide/mm/hugetlbpage.rst. + Format: size[KMG] deferred_probe_timeout= [KNL] Debugging option to set a timeout in seconds for @@ -1479,13 +1482,24 @@ hugepages using the cma allocator. If enabled, the boot-time allocation of gigantic hugepages is skipped. - hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot. - hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages. - On x86-64 and powerpc, this option can be specified - multiple times interleaved with hugepages= to reserve - huge pages of different sizes. Valid pages sizes on - x86-64 are 2M (when the CPU supports "pse") and 1G - (when the CPU supports the "pdpe1gb" cpuinfo flag). + hugepages= [HW] Number of HugeTLB pages to allocate at boot. + If this follows hugepagesz (below), it specifies + the number of pages of hugepagesz to be allocated. + If this is the first HugeTLB parameter on the command + line, it specifies the number of pages to allocate for + the default huge page size. See also + Documentation/admin-guide/mm/hugetlbpage.rst. + Format: <integer> + + hugepagesz= + [HW] The size of the HugeTLB pages. This is used in + conjunction with hugepages (above) to allocate huge + pages of a specific size at boot. The pair + hugepagesz=X hugepages=Y can be specified once for + each supported huge page size. Huge page sizes are + architecture dependent. See also + Documentation/admin-guide/mm/hugetlbpage.rst. + Format: size[KMG] hung_task_panic= [KNL] Should the hung task detector generate panics. diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst index 1cc0bc78d10e..5026e58826e2 100644 --- a/Documentation/admin-guide/mm/hugetlbpage.rst +++ b/Documentation/admin-guide/mm/hugetlbpage.rst @@ -100,6 +100,41 @@ with a huge page size selection parameter "hugepagesz=<size>". <size> must be specified in bytes with optional scale suffix [kKmMgG]. The default huge page size may be selected with the "default_hugepagesz=<size>" boot parameter. +Hugetlb boot command line parameter semantics +hugepagesz - Specify a huge page size. Used in conjunction with hugepages + parameter to preallocate a number of huge pages of the specified + size. Hence, hugepagesz and hugepages are typically specified in + pairs such as: + hugepagesz=2M hugepages=512 + hugepagesz can only be specified once on the command line for a + specific huge page size. Valid huge page sizes are architecture + dependent. +hugepages - Specify the number of huge pages to preallocate. This typically + follows a valid hugepagesz or default_hugepagesz parameter. However, + if hugepages is the first or only hugetlb command line parameter it + implicitly specifies the number of huge pages of default size to + allocate. If the number of huge pages of default size is implicitly + specified, it can not be overwritten by a hugepagesz,hugepages + parameter pair for the default size. + For example, on an architecture with 2M default huge page size: + hugepages=256 hugepagesz=2M hugepages=512 + will result in 256 2M huge pages being allocated and a warning message + indicating that the hugepages=512 parameter is ignored. If a hugepages + parameter is preceded by an invalid hugepagesz parameter, it will + be ignored. +default_hugepagesz - Specify the default huge page size. This parameter can + only be specified once on the command line. default_hugepagesz can + optionally be followed by the hugepages parameter to preallocate a + specific number of huge pages of default size. The number of default + sized huge pages to preallocate can also be implicitly specified as + mentioned in the hugepages section above. Therefore, on an + architecture with 2M default huge page size: + hugepages=256 + default_hugepagesz=2M hugepages=256 + hugepages=256 default_hugepagesz=2M + will all result in 256 2M huge pages being allocated. Valid default + huge page size is architecture dependent. + When multiple huge page sizes are supported, ``/proc/sys/vm/nr_hugepages`` indicates the current number of pre-allocated huge pages of the default size. Thus, one can use the following command to dynamically allocate/deallocate diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 2ae0e506cfc7..786004514d10 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -59,8 +59,8 @@ __initdata LIST_HEAD(huge_boot_pages); /* for command line parsing */ static struct hstate * __initdata parsed_hstate; static unsigned long __initdata default_hstate_max_huge_pages; -static unsigned long __initdata default_hstate_size; static bool __initdata parsed_valid_hugepagesz = true; +static bool __initdata parsed_default_hugepagesz; /* * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages, @@ -3060,7 +3060,7 @@ static void __init hugetlb_sysfs_init(void) err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, hstate_kobjs, &hstate_attr_group); if (err) - pr_err("Hugetlb: Unable to add hstate %s", h->name); + pr_err("HugeTLB: Unable to add hstate %s", h->name); } } @@ -3164,7 +3164,7 @@ static void hugetlb_register_node(struct node *node) nhs->hstate_kobjs, &per_node_hstate_attr_group); if (err) { - pr_err("Hugetlb: Unable to add hstate %s for node %d\n", + pr_err("HugeTLB: Unable to add hstate %s for node %d\n", h->name, node->dev.id); hugetlb_unregister_node(node); break; @@ -3215,19 +3215,35 @@ static int __init hugetlb_init(void) if (!hugepages_supported()) return 0; - if (!size_to_hstate(default_hstate_size)) { - if (default_hstate_size != 0) { - pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n", - default_hstate_size, HPAGE_SIZE); + /* + * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some + * architectures depend on setup being done here. + */ + hugetlb_add_hstate(HUGETLB_PAGE_ORDER); + if (!parsed_default_hugepagesz) { + /* + * If we did not parse a default huge page size, set + * default_hstate_idx to HPAGE_SIZE hstate. And, if the + * number of huge pages for this default size was implicitly + * specified, set that here as well. + * Note that the implicit setting will overwrite an explicit + * setting. A warning will be printed in this case. + */ + default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE)); + if (default_hstate_max_huge_pages) { + if (default_hstate.max_huge_pages) { + char buf[32]; + + string_get_size(huge_page_size(&default_hstate), + 1, STRING_UNITS_2, buf, 32); + pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n", + default_hstate.max_huge_pages, buf); + pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n", + default_hstate_max_huge_pages); + } + default_hstate.max_huge_pages = + default_hstate_max_huge_pages; } - - default_hstate_size = HPAGE_SIZE; - hugetlb_add_hstate(HUGETLB_PAGE_ORDER); - } - default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size)); - if (default_hstate_max_huge_pages) { - if (!default_hstate.max_huge_pages) - default_hstate.max_huge_pages = default_hstate_max_huge_pages; } hugetlb_cma_check(); @@ -3287,20 +3303,34 @@ void __init hugetlb_add_hstate(unsigned int order) parsed_hstate = h; } -static int __init hugetlb_nrpages_setup(char *s) +/* + * hugepages command line processing + * hugepages normally follows a valid hugepagsz or default_hugepagsz + * specification. If not, ignore the hugepages value. hugepages can also + * be the first huge page command line option in which case it implicitly + * specifies the number of huge pages for the default size. + */ +static int __init hugepages_setup(char *s) { unsigned long *mhp; static unsigned long *last_mhp; + if (!hugepages_supported()) { + pr_warn("HugeTLB: huge pages not supported, ignoring hugepages = %s\n", s); + return 0; + } + if (!parsed_valid_hugepagesz) { - pr_warn("hugepages = %s preceded by " - "an unsupported hugepagesz, ignoring\n", s); + pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s); parsed_valid_hugepagesz = true; - return 1; + return 0; } + /* - * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet, - * so this hugepages= parameter goes to the "default hstate". + * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter + * yet, so this hugepages= parameter goes to the "default hstate". + * Otherwise, it goes with the previously parsed hugepagesz or + * default_hugepagesz. */ else if (!hugetlb_max_hstate) mhp = &default_hstate_max_huge_pages; @@ -3308,8 +3338,8 @@ static int __init hugetlb_nrpages_setup(char *s) mhp = &parsed_hstate->max_huge_pages; if (mhp == last_mhp) { - pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n"); - return 1; + pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s); + return 0; } if (sscanf(s, "%lu", mhp) <= 0) @@ -3327,42 +3357,109 @@ static int __init hugetlb_nrpages_setup(char *s) return 1; } -__setup("hugepages=", hugetlb_nrpages_setup); +__setup("hugepages=", hugepages_setup); +/* + * hugepagesz command line processing + * A specific huge page size can only be specified once with hugepagesz. + * hugepagesz is followed by hugepages on the command line. The global + * variable 'parsed_valid_hugepagesz' is used to determine if prior + * hugepagesz argument was valid. + */ static int __init hugepagesz_setup(char *s) { unsigned long size; + struct hstate *h; + + parsed_valid_hugepagesz = false; + if (!hugepages_supported()) { + pr_warn("HugeTLB: huge pages not supported, ignoring hugepagesz = %s\n", s); + return 0; + } size = (unsigned long)memparse(s, NULL); if (!arch_hugetlb_valid_size(size)) { - parsed_valid_hugepagesz = false; - pr_err("HugeTLB: unsupported hugepagesz %s\n", s); + pr_err("HugeTLB: unsupported hugepagesz=%s\n", s); return 0; } - if (size_to_hstate(size)) { - pr_warn("HugeTLB: hugepagesz %s specified twice, ignoring\n", s); - return 0; + h = size_to_hstate(size); + if (h) { + /* + * hstate for this size already exists. This is normally + * an error, but is allowed if the existing hstate is the + * default hstate. More specifically, it is only allowed if + * the number of huge pages for the default hstate was not + * previously specified. + */ + if (!parsed_default_hugepagesz || h != &default_hstate || + default_hstate.max_huge_pages) { + pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s); + return 0; + } + + /* + * No need to call hugetlb_add_hstate() as hstate already + * exists. But, do set parsed_hstate so that a following + * hugepages= parameter will be applied to this hstate. + */ + parsed_hstate = h; + parsed_valid_hugepagesz = true; + return 1; } hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT); + parsed_valid_hugepagesz = true; return 1; } __setup("hugepagesz=", hugepagesz_setup); +/* + * default_hugepagesz command line input + * Only one instance of default_hugepagesz allowed on command line. + */ static int __init default_hugepagesz_setup(char *s) { unsigned long size; + parsed_valid_hugepagesz = false; + if (!hugepages_supported()) { + pr_warn("HugeTLB: huge pages not supported, ignoring default_hugepagesz = %s\n", s); + return 0; + } + + if (parsed_default_hugepagesz) { + pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s); + return 0; + } + size = (unsigned long)memparse(s, NULL); if (!arch_hugetlb_valid_size(size)) { - pr_err("HugeTLB: unsupported default_hugepagesz %s\n", s); + pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s); return 0; } - default_hstate_size = size; + hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT); + parsed_valid_hugepagesz = true; + parsed_default_hugepagesz = true; + default_hstate_idx = hstate_index(size_to_hstate(size)); + + /* + * The number of default huge pages (for this size) could have been + * specified as the first hugetlb parameter: hugepages=X. If so, + * then default_hstate_max_huge_pages is set. If the default huge + * page size is gigantic (>= MAX_ORDER), then the pages must be + * allocated here from bootmem allocator. + */ + if (default_hstate_max_huge_pages) { + default_hstate.max_huge_pages = default_hstate_max_huge_pages; + if (hstate_is_gigantic(&default_hstate)) + hugetlb_hstate_alloc_pages(&default_hstate); + default_hstate_max_huge_pages = 0; + } + return 1; } __setup("default_hugepagesz=", default_hugepagesz_setup); |