On Fri, Mar 13, 2026 at 04:06:37PM +0000, Anatoly Burakov wrote:
> Currently, the VA space limits placed on DPDK memory are only informed by
> the default configuration coming from `rte_config.h` file. Add an EAL flag
> to specify per-page size memory limits explicitly, thereby overriding the
> default VA space reservations.
>
> Signed-off-by: Anatoly Burakov <[email protected]>
> ---
Acked-by: Bruce Richardson <[email protected]>
CI reports some errors with 32-bit builds. Also a couple of small comments
inline below.
Thanks for the series, looks some nice simplification.
> app/test/test.c | 1 +
> app/test/test_eal_flags.c | 126 ++++++++++++++++++
> doc/guides/linux_gsg/linux_eal_parameters.rst | 13 ++
> .../prog_guide/env_abstraction_layer.rst | 27 +++-
> lib/eal/common/eal_common_dynmem.c | 9 ++
> lib/eal/common/eal_common_options.c | 121 +++++++++++++++++
> lib/eal/common/eal_internal_cfg.h | 6 +
> lib/eal/common/eal_option_list.h | 1 +
> 8 files changed, 302 insertions(+), 2 deletions(-)
>
> diff --git a/app/test/test.c b/app/test/test.c
> index 58ef52f312..c610c3588e 100644
> --- a/app/test/test.c
> +++ b/app/test/test.c
> @@ -80,6 +80,7 @@ do_recursive_call(void)
> { "test_memory_flags", no_action },
> { "test_file_prefix", no_action },
> { "test_no_huge_flag", no_action },
> + { "test_pagesz_mem_flags", no_action },
> { "test_panic", test_panic },
> { "test_exit", test_exit },
> #ifdef RTE_LIB_TIMER
> diff --git a/app/test/test_eal_flags.c b/app/test/test_eal_flags.c
> index b3a8d0ae6f..4e1038be75 100644
> --- a/app/test/test_eal_flags.c
> +++ b/app/test/test_eal_flags.c
> @@ -95,6 +95,14 @@ test_misc_flags(void)
> return TEST_SKIPPED;
> }
>
> +static int
> +test_pagesz_mem_flags(void)
> +{
> + printf("pagesz_mem_flags not supported on Windows, skipping test\n");
> + return TEST_SKIPPED;
> +}
> +
> +
> #else
>
> #include <libgen.h>
> @@ -1502,6 +1510,123 @@ populate_socket_mem_param(int num_sockets, const char
> *mem,
> offset += written;
> }
>
> +/*
> + * Tests for correct handling of --pagesz-mem flag
> + */
> +static int
> +test_pagesz_mem_flags(void)
> +{
> +#ifdef RTE_EXEC_ENV_FREEBSD
> + /* FreeBSD does not support --pagesz-mem */
> + return 0;
> +#else
> + const char *in_memory = "--in-memory";
> +
> + /* invalid: no value */
> + const char * const argv0[] = {prgname, eal_debug_logs, no_pci,
> + "--file-prefix=" memtest, in_memory, "--pagesz-mem="};
> +
> + /* invalid: no colon (missing limit) */
> + const char * const argv1[] = {prgname, eal_debug_logs, no_pci,
> + "--file-prefix=" memtest, in_memory, "--pagesz-mem=2M"};
> +
> + /* invalid: colon present but limit is empty */
> + const char * const argv2[] = {prgname, eal_debug_logs, no_pci,
> + "--file-prefix=" memtest, in_memory,
> "--pagesz-mem=2M:"};
> +
> + /* invalid: limit not aligned to page size (3M is not a multiple of 2M)
> */
> + const char * const argv3[] = {prgname, eal_debug_logs, no_pci,
> + "--file-prefix=" memtest, in_memory,
> "--pagesz-mem=2M:3M"};
> +
> + /* invalid: garbage value */
> + const char * const argv4[] = {prgname, eal_debug_logs, no_pci,
> + "--file-prefix=" memtest, in_memory,
> "--pagesz-mem=garbage"};
> +
> + /* invalid: garbage value */
> + const char * const argv5[] = {prgname, eal_debug_logs, no_pci,
> + "--file-prefix=" memtest, in_memory,
> "--pagesz-mem=2M:garbage"};
> +
> + /* invalid: --pagesz-mem combined with --no-huge */
> + const char * const argv6[] = {prgname, eal_debug_logs, no_pci,
> + "--file-prefix=" memtest, in_memory, no_huge,
> "--pagesz-mem=2M:2M"};
> +
> + /* valid: single well-formed aligned pair */
> + const char * const argv7[] = {prgname, eal_debug_logs, no_pci,
> + "--file-prefix=" memtest, in_memory,
> "--pagesz-mem=2M:64M"};
> +
> + /* valid: multiple occurrences */
> + const char * const argv8[] = {prgname, eal_debug_logs, no_pci,
> + "--file-prefix=" memtest, in_memory,
> + "--pagesz-mem=2M:64M", "--pagesz-mem=1K:8K"};
> +
> + /* valid: fake page size set to zero (ignored but syntactically valid)
> */
> + const char * const argv9[] = {prgname, eal_debug_logs, no_pci,
> + "--file-prefix=" memtest, in_memory,
> "--pagesz-mem=1K:0"};
> +
> + /* invalid: page size must be a power of two */
> + const char * const argv10[] = {prgname, eal_debug_logs, no_pci,
> + "--file-prefix=" memtest, in_memory,
> "--pagesz-mem=3M:6M"};
> +
> + if (launch_proc(argv0) == 0) {
> + printf("Error (line %d) - process run ok with empty
> --pagesz-mem!\n",
> + __LINE__);
> + return -1;
> + }
> + if (launch_proc(argv1) == 0) {
> + printf("Error (line %d) - process run ok with --pagesz-mem
> missing colon!\n",
> + __LINE__);
> + return -1;
> + }
> + if (launch_proc(argv2) == 0) {
> + printf("Error (line %d) - process run ok with --pagesz-mem
> missing limit!\n",
> + __LINE__);
> + return -1;
> + }
> + if (launch_proc(argv3) == 0) {
> + printf("Error (line %d) - process run ok with --pagesz-mem
> unaligned limit!\n",
> + __LINE__);
> + return -1;
> + }
> + if (launch_proc(argv4) == 0) {
> + printf("Error (line %d) - process run ok with --pagesz-mem
> garbage value!\n",
> + __LINE__);
> + return -1;
> + }
> + if (launch_proc(argv5) == 0) {
> + printf("Error (line %d) - process run ok with --pagesz-mem
> garbage value!\n",
> + __LINE__);
> + return -1;
> + }
> + if (launch_proc(argv6) == 0) {
> + printf("Error (line %d) - process run ok with --pagesz-mem and
> --no-huge!\n",
> + __LINE__);
> + return -1;
> + }
> + if (launch_proc(argv7) != 0) {
> + printf("Error (line %d) - process failed with valid
> --pagesz-mem!\n",
> + __LINE__);
> + return -1;
> + }
> + if (launch_proc(argv8) != 0) {
> + printf("Error (line %d) - process failed with multiple valid
> --pagesz-mem!\n",
> + __LINE__);
> + return -1;
> + }
> + if (launch_proc(argv9) != 0) {
> + printf("Error (line %d) - process failed with --pagesz-mem zero
> limit!\n",
> + __LINE__);
> + return -1;
> + }
> + if (launch_proc(argv10) == 0) {
> + printf("Error (line %d) - process run ok with non-power-of-two
> pagesz!\n",
> + __LINE__);
> + return -1;
> + }
> +
> + return 0;
> +#endif /* !RTE_EXEC_ENV_FREEBSD */
> +}
> +
> /*
> * Tests for correct handling of -m and --socket-mem flags
> */
> @@ -1683,5 +1808,6 @@ REGISTER_FAST_TEST(eal_flags_b_opt_autotest,
> NOHUGE_SKIP, ASAN_SKIP, test_invali
> REGISTER_FAST_TEST(eal_flags_vdev_opt_autotest, NOHUGE_SKIP, ASAN_SKIP,
> test_invalid_vdev_flag);
> REGISTER_FAST_TEST(eal_flags_r_opt_autotest, NOHUGE_SKIP, ASAN_SKIP,
> test_invalid_r_flag);
> REGISTER_FAST_TEST(eal_flags_mem_autotest, NOHUGE_SKIP, ASAN_SKIP,
> test_memory_flags);
> +REGISTER_FAST_TEST(eal_flags_pagesz_mem_autotest, NOHUGE_SKIP, ASAN_SKIP,
> test_pagesz_mem_flags);
> REGISTER_FAST_TEST(eal_flags_file_prefix_autotest, NOHUGE_SKIP, ASAN_SKIP,
> test_file_prefix);
> REGISTER_FAST_TEST(eal_flags_misc_autotest, NOHUGE_SKIP, ASAN_SKIP,
> test_misc_flags);
> diff --git a/doc/guides/linux_gsg/linux_eal_parameters.rst
> b/doc/guides/linux_gsg/linux_eal_parameters.rst
> index 7c5b26ce26..ce38dd128a 100644
> --- a/doc/guides/linux_gsg/linux_eal_parameters.rst
> +++ b/doc/guides/linux_gsg/linux_eal_parameters.rst
> @@ -75,6 +75,19 @@ Memory-related options
> Place a per-NUMA node upper limit on memory use (non-legacy memory mode
> only).
> 0 will disable the limit for a particular NUMA node.
>
> +* ``--pagesz-mem <page size:limit>``
> +
> + Set memory limit per hugepage size.
> + Each time the option is used, provide a single ``<pagesz>:<limit>`` pair;
> + repeat the option to specify additional page sizes.
> + Both values support K/M/G/T suffixes (for example ``2M:32G``).
> +
> + The memory limit must be a multiple of page size.
> +
> + For example::
> +
> + --pagesz-mem 2M:32G --pagesz-mem 1G:512G
> +
> * ``--single-file-segments``
>
> Create fewer files in hugetlbfs (non-legacy mode only).
> diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst
> b/doc/guides/prog_guide/env_abstraction_layer.rst
> index 63e0568afa..e2adf0a184 100644
> --- a/doc/guides/prog_guide/env_abstraction_layer.rst
> +++ b/doc/guides/prog_guide/env_abstraction_layer.rst
> @@ -204,13 +204,36 @@ of virtual memory being preallocated at startup by
> editing the following config
> variables:
>
> * ``RTE_MAX_MEMSEG_LISTS`` controls how many segment lists can DPDK have
> -* ``RTE_MAX_MEMSEG_PER_TYPE`` controls how many segments each memory type
> +* ``RTE_MAX_MEMSEG_PER_TYPE`` sets the default number of segments each
> memory type
> can have (where "type" is defined as "page size + NUMA node" combination)
> -* ``RTE_MAX_MEM_MB_PER_TYPE`` controls how much megabytes of memory each
> +* ``RTE_MAX_MEM_MB_PER_TYPE`` sets the default amount of memory each
> memory type can address
>
> Normally, these options do not need to be changed.
>
> +Runtime Override of Per-Page-Size Memory Limits
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +By default, DPDK uses compile-time configured limits for memory allocation
> per page size
> +(as set by ``RTE_MAX_MEM_MB_PER_TYPE``).
> +These limits apply uniformly across all NUMA nodes for a given page size.
> +
> +It is possible to override these defaults at runtime using the
> ``--pagesz-mem`` option,
> +which allows specifying custom memory limits for each page size. This is
> useful when:
> +
> +* The default limits may be insufficient or excessive for your workload
> +* You want to dedicate more memory to specific page sizes
> +
> +The ``--pagesz-mem`` option accepts exactly one ``<pagesz>:<limit>`` pair per
> +occurrence, where ``pagesz`` is a page size (e.g., ``2M``, ``4M``, ``1G``)
> +and ``limit`` is the maximum memory to reserve for that page size (e.g.,
> ``64G``, ``512M``).
> +Both values support standard binary suffixes (K, M, G, T).
> +Memory limits must be aligned to their corresponding page size.
> +
> +Multiple page sizes can be specified by repeating the option::
> +
> + --pagesz-mem 2M:64G --pagesz-mem 1G:512G
> +
> .. note::
>
> Preallocated virtual memory is not to be confused with preallocated
> hugepage
> diff --git a/lib/eal/common/eal_common_dynmem.c
> b/lib/eal/common/eal_common_dynmem.c
> index c33fbdea6d..7096f46ff3 100644
> --- a/lib/eal/common/eal_common_dynmem.c
> +++ b/lib/eal/common/eal_common_dynmem.c
> @@ -127,6 +127,11 @@ eal_dynmem_memseg_lists_init(void)
> mem_va_len += type->mem_sz;
> }
>
> + if (mem_va_len == 0) {
> + EAL_LOG(ERR, "No virtual memory will be reserved");
> + goto out;
> + }
> +
> mem_va_addr = eal_get_virtual_area(NULL, &mem_va_len,
> mem_va_page_sz, 0, 0);
> if (mem_va_addr == NULL) {
> @@ -141,6 +146,10 @@ eal_dynmem_memseg_lists_init(void)
> uint64_t pagesz;
> int socket_id;
>
> + /* skip page sizes with zero memory limit */
> + if (type->n_segs == 0)
> + continue;
> +
> pagesz = type->page_sz;
> socket_id = type->socket_id;
>
> diff --git a/lib/eal/common/eal_common_options.c
> b/lib/eal/common/eal_common_options.c
> index bbc4427524..0532d27aaa 100644
> --- a/lib/eal/common/eal_common_options.c
> +++ b/lib/eal/common/eal_common_options.c
> @@ -21,6 +21,7 @@
> #endif
>
> #include <rte_string_fns.h>
> +#include <rte_common.h>
> #include <rte_eal.h>
> #include <rte_log.h>
> #include <rte_lcore.h>
> @@ -233,6 +234,20 @@ eal_collate_args(int argc, char **argv)
> EAL_LOG(ERR, "Options allow (-a) and block (-b) can't be used
> at the same time");
> return -1;
> }
> +#ifdef RTE_EXEC_ENV_FREEBSD
> + if (!TAILQ_EMPTY(&args.pagesz_mem)) {
> + EAL_LOG(ERR, "Option pagesz-mem is not supported on FreeBSD");
> + return -1;
> + }
> +#endif
> + if (!TAILQ_EMPTY(&args.pagesz_mem) && args.no_huge) {
> + EAL_LOG(ERR, "Options pagesz-mem and no-huge can't be used at
> the same time");
> + return -1;
> + }
> + if (!TAILQ_EMPTY(&args.pagesz_mem) && args.legacy_mem) {
> + EAL_LOG(ERR, "Options pagesz-mem and legacy-mem can't be used
> at the same time");
> + return -1;
> + }
>
> /* for non-list args, we can just check for zero/null values using
> macro */
> if (CONFLICTING_OPTIONS(args, coremask, lcores) ||
> @@ -511,7 +526,10 @@ eal_reset_internal_config(struct internal_config
> *internal_cfg)
> sizeof(internal_cfg->hugepage_info[0]));
> internal_cfg->hugepage_info[i].lock_descriptor = -1;
> internal_cfg->hugepage_mem_sz_limits[i] = 0;
> + internal_cfg->pagesz_mem_overrides[i].pagesz = 0;
> + internal_cfg->pagesz_mem_overrides[i].limit = 0;
> }
> + internal_cfg->num_pagesz_mem_overrides = 0;
> internal_cfg->base_virtaddr = 0;
>
> /* if set to NONE, interrupt mode is determined automatically */
> @@ -1867,6 +1885,96 @@ eal_parse_socket_arg(char *strval, volatile uint64_t
> *socket_arg)
> return 0;
> }
>
> +static int
> +eal_parse_pagesz_mem(char *strval, struct internal_config *internal_cfg)
> +{
> + char strval_cpy[1024];
> + char *fields[3];
> + char *pagesz_str, *mem_str;
> + int arg_num;
> + int len;
> + unsigned int i;
> + uint64_t pagesz, mem_limit;
> + struct pagesz_mem_override *pmo;
> +
> + len = strnlen(strval, 1024);
> + if (len >= 1024) {
> + EAL_LOG(ERR, "--pagesz-mem parameter is too long");
> + return -1;
> + }
> +
> + rte_strlcpy(strval_cpy, strval, sizeof(strval_cpy));
> +
> + /* parse exactly one pagesz:mem pair per --pagesz-mem option */
> + arg_num = rte_strsplit(strval_cpy, len, fields, RTE_DIM(fields), ':');
> + if (arg_num != 2 || fields[0][0] == '\0' || fields[1][0] == '\0') {
> + EAL_LOG(ERR, "--pagesz-mem parameter format is invalid,
> expected <pagesz>:<limit>");
> + return -1;
> + }
> + pagesz_str = fields[0];
> + mem_str = fields[1];
> +
> + /* reject accidental multiple pairs in one option */
> + if (strchr(mem_str, ',') != NULL) {
> + EAL_LOG(ERR, "--pagesz-mem accepts one <pagesz>:<limit> pair
> per option");
> + return -1;
> + }
If multiple options are given, then the rte_strsplit should return >2 when
splitting on ":". I'd suggest checking for the comma first, before even
doing the strlcpy.
> +
> + /* parse page size */
> + errno = 0;
> + pagesz = rte_str_to_size(pagesz_str);
> + if (pagesz == 0 || errno != 0) {
> + EAL_LOG(ERR, "invalid page size in --pagesz-mem: '%s'",
> pagesz_str);
> + return -1;
> + }
> + if (!rte_is_power_of_2(pagesz)) {
> + EAL_LOG(ERR, "invalid page size in --pagesz-mem: '%s' (must be
> a power of two)",
> + pagesz_str);
> + return -1;
> + }
> +
> + /* parse memory limit (0 is valid: disables allocation for this page
> size) */
> + errno = 0;
> + mem_limit = rte_str_to_size(mem_str);
> + if (errno != 0) {
> + EAL_LOG(ERR, "invalid memory limit in --pagesz-mem: '%s'",
> mem_str);
> + return -1;
> + }
> +
> + /* validate alignment: memory limit must be divisible by page size */
> + if (mem_limit % pagesz != 0) {
> + EAL_LOG(ERR, "--pagesz-mem memory limit must be aligned to page
> size");
> + return -1;
> + }
> +
> + for (i = 0; i < internal_cfg->num_pagesz_mem_overrides; i++) {
> + pmo = &internal_cfg->pagesz_mem_overrides[i];
> + if (pmo->pagesz != pagesz)
> + continue;
> +
> + EAL_LOG(WARNING,
> + "--pagesz-mem specified multiple times for page size
> '%s'; later limit '%s' will be used",
> + pagesz_str, mem_str);
> + pmo->limit = mem_limit;
> + return 0;
Rather than just warning, I'd make this a hard error and say you can't
duplicate the hugepage limits on commandline. Saves confusion when
examining a commandline, having to check if a value is overridden later.
> + }
> +
> + /* do we have space? */
> + if (internal_cfg->num_pagesz_mem_overrides >= MAX_HUGEPAGE_SIZES) {
> + EAL_LOG(ERR,
> + "--pagesz-mem: too many page size entries (max %d)",
> + MAX_HUGEPAGE_SIZES);
> + return -1;
> + }
> +
> + pmo =
> &internal_cfg->pagesz_mem_overrides[internal_cfg->num_pagesz_mem_overrides];
> + pmo->pagesz = pagesz;
> + pmo->limit = mem_limit;
> + internal_cfg->num_pagesz_mem_overrides++;
> +
> + return 0;
> +}
> +
> static int
> eal_parse_vfio_intr(const char *mode)
> {
> @@ -2172,6 +2280,12 @@ eal_parse_args(void)
> }
> int_cfg->force_numa_limits = 1;
> }
> + TAILQ_FOREACH(arg, &args.pagesz_mem, next) {
> + if (eal_parse_pagesz_mem(arg->arg, int_cfg) < 0) {
> + EAL_LOG(ERR, "invalid pagesz-mem parameter: '%s'",
> arg->arg);
> + return -1;
> + }
> + }
>
> /* tracing settings, not supported on windows */
> #ifdef RTE_EXEC_ENV_WINDOWS
> @@ -2366,6 +2480,7 @@ eal_apply_hugepage_mem_sz_limits(struct internal_config
> *internal_cfg)
> unsigned int i;
>
> for (i = 0; i < internal_cfg->num_hugepage_sizes; i++) {
> + unsigned int j;
> const uint64_t pagesz =
> internal_cfg->hugepage_info[i].hugepage_sz;
> uint64_t limit;
>
> @@ -2373,6 +2488,12 @@ eal_apply_hugepage_mem_sz_limits(struct
> internal_config *internal_cfg)
> limit = RTE_MIN((uint64_t)RTE_MAX_MEM_MB_PER_TYPE << 20,
> (uint64_t)RTE_MAX_MEMSEG_PER_TYPE * pagesz);
>
> + /* override with user value for matching page size */
> + for (j = 0; j < (unsigned
> int)internal_cfg->num_pagesz_mem_overrides; j++) {
> + if (internal_cfg->pagesz_mem_overrides[j].pagesz ==
> pagesz)
> + limit =
> internal_cfg->pagesz_mem_overrides[j].limit;
> + }
> +
> internal_cfg->hugepage_mem_sz_limits[i] = limit;
> }
>
> diff --git a/lib/eal/common/eal_internal_cfg.h
> b/lib/eal/common/eal_internal_cfg.h
> index 0bf192c6e5..8475c87969 100644
> --- a/lib/eal/common/eal_internal_cfg.h
> +++ b/lib/eal/common/eal_internal_cfg.h
> @@ -98,6 +98,12 @@ struct internal_config {
> struct hugepage_info hugepage_info[MAX_HUGEPAGE_SIZES];
> uint64_t hugepage_mem_sz_limits[MAX_HUGEPAGE_SIZES];
> /**< default max memory per hugepage size */
> + /** storage for user-specified pagesz-mem overrides */
> + struct pagesz_mem_override {
> + uint64_t pagesz; /**< page size in bytes */
> + uint64_t limit; /**< memory limit in bytes */
> + } pagesz_mem_overrides[MAX_HUGEPAGE_SIZES];
> + unsigned int num_pagesz_mem_overrides; /**< number of stored overrides
> */
> enum rte_iova_mode iova_mode ; /**< Set IOVA mode on this system */
> rte_cpuset_t ctrl_cpuset; /**< cpuset for ctrl threads */
> volatile unsigned int init_complete;
> diff --git a/lib/eal/common/eal_option_list.h
> b/lib/eal/common/eal_option_list.h
> index abee16340b..164a0b3888 100644
> --- a/lib/eal/common/eal_option_list.h
> +++ b/lib/eal/common/eal_option_list.h
> @@ -56,6 +56,7 @@ BOOL_ARG("--no-huge", NULL, "Disable hugetlbfs support",
> no_huge)
> BOOL_ARG("--no-pci", NULL, "Disable all PCI devices", no_pci)
> BOOL_ARG("--no-shconf", NULL, "Disable shared config file generation",
> no_shconf)
> BOOL_ARG("--no-telemetry", NULL, "Disable telemetry", no_telemetry)
> +LIST_ARG("--pagesz-mem", NULL, "Memory allocation per hugepage size (format:
> <pagesz>:<limit>, e.g. 2M:32G). Repeat option for multiple page sizes.",
> pagesz_mem)
> STR_ARG("--proc-type", NULL, "Type of process (primary|secondary|auto)",
> proc_type)
> OPT_STR_ARG("--remap-lcore-ids", "-R", "Remap lcore IDs to be contiguous
> starting from 0, or supplied value", remap_lcore_ids)
> STR_ARG("--service-corelist", "-S", "List of cores to use for service
> threads", service_corelist)
> --
> 2.47.3
>
