On 3/8/2016 9:42 AM, Jianfeng Tan wrote:
> This patch adds an option, --huge-trybest, to use a recover mechanism to
> the case that there are not so many hugepages (declared in sysfs), which
> can be used. It relys on a mem access to fault-in hugepages, and if fails
> with SIGBUS, recover to previously saved stack environment with
> siglongjmp().
>
> Test example:
> a. cgcreate -g hugetlb:/test-subgroup
> b. cgset -r hugetlb.1GB.limit_in_bytes=2147483648 test-subgroup
> c. cgexec -g hugetlb:test-subgroup \
> ./examples/helloworld/build/helloworld -c 0x2 -n 4 --huge-trybest
>
> Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com>
Sorry, forgot to add ack from Neil.
Acked-by: Neil Horman <nhorman at tuxdriver.com>
> ---
> v2:
> - Address the compiling error by move setjmp into a wrap method.
>
> lib/librte_eal/common/eal_common_options.c | 4 ++
> lib/librte_eal/common/eal_internal_cfg.h | 1 +
> lib/librte_eal/common/eal_options.h | 2 +
> lib/librte_eal/linuxapp/eal/eal.c | 1 +
> lib/librte_eal/linuxapp/eal/eal_memory.c | 104
> ++++++++++++++++++++++++++---
> 5 files changed, 104 insertions(+), 8 deletions(-)
>
> diff --git a/lib/librte_eal/common/eal_common_options.c
> b/lib/librte_eal/common/eal_common_options.c
> index 29942ea..8ff6a2e 100644
> --- a/lib/librte_eal/common/eal_common_options.c
> +++ b/lib/librte_eal/common/eal_common_options.c
> @@ -95,6 +95,7 @@ eal_long_options[] = {
> {OPT_VFIO_INTR, 1, NULL, OPT_VFIO_INTR_NUM },
> {OPT_VMWARE_TSC_MAP, 0, NULL, OPT_VMWARE_TSC_MAP_NUM },
> {OPT_XEN_DOM0, 0, NULL, OPT_XEN_DOM0_NUM },
> + {OPT_HUGE_TRYBEST, 0, NULL, OPT_HUGE_TRYBEST_NUM },
> {0, 0, NULL, 0 }
> };
>
> @@ -896,6 +897,9 @@ eal_parse_common_option(int opt, const char *optarg,
> return -1;
> }
> break;
> + case OPT_HUGE_TRYBEST_NUM:
> + internal_config.huge_trybest = 1;
> + break;
>
> /* don't know what to do, leave this to caller */
> default:
> diff --git a/lib/librte_eal/common/eal_internal_cfg.h
> b/lib/librte_eal/common/eal_internal_cfg.h
> index 5f1367e..90a3533 100644
> --- a/lib/librte_eal/common/eal_internal_cfg.h
> +++ b/lib/librte_eal/common/eal_internal_cfg.h
> @@ -64,6 +64,7 @@ struct internal_config {
> volatile unsigned force_nchannel; /**< force number of channels */
> volatile unsigned force_nrank; /**< force number of ranks */
> volatile unsigned no_hugetlbfs; /**< true to disable hugetlbfs */
> + volatile unsigned huge_trybest; /**< try best to allocate hugepages */
> unsigned hugepage_unlink; /**< true to unlink backing files */
> volatile unsigned xen_dom0_support; /**< support app running on Xen
> Dom0*/
> volatile unsigned no_pci; /**< true to disable PCI */
> diff --git a/lib/librte_eal/common/eal_options.h
> b/lib/librte_eal/common/eal_options.h
> index a881c62..02397c5 100644
> --- a/lib/librte_eal/common/eal_options.h
> +++ b/lib/librte_eal/common/eal_options.h
> @@ -83,6 +83,8 @@ enum {
> OPT_VMWARE_TSC_MAP_NUM,
> #define OPT_XEN_DOM0 "xen-dom0"
> OPT_XEN_DOM0_NUM,
> +#define OPT_HUGE_TRYBEST "huge-trybest"
> + OPT_HUGE_TRYBEST_NUM,
> OPT_LONG_MAX_NUM
> };
>
> diff --git a/lib/librte_eal/linuxapp/eal/eal.c
> b/lib/librte_eal/linuxapp/eal/eal.c
> index ceac435..3e23877 100644
> --- a/lib/librte_eal/linuxapp/eal/eal.c
> +++ b/lib/librte_eal/linuxapp/eal/eal.c
> @@ -343,6 +343,7 @@ eal_usage(const char *prgname)
> " --"OPT_CREATE_UIO_DEV" Create /dev/uioX (usually done by
> hotplug)\n"
> " --"OPT_VFIO_INTR" Interrupt mode for VFIO
> (legacy|msi|msix)\n"
> " --"OPT_XEN_DOM0" Support running on Xen dom0 without
> hugetlbfs\n"
> + " --"OPT_HUGE_TRYBEST" Try best to accommodate hugepages\n"
> "\n");
> /* Allow the application to print its usage message too if hook is set
> */
> if ( rte_application_usage_hook ) {
> diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c
> b/lib/librte_eal/linuxapp/eal/eal_memory.c
> index 5b9132c..e4e1f3b 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_memory.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
> @@ -80,6 +80,8 @@
> #include <errno.h>
> #include <sys/ioctl.h>
> #include <sys/time.h>
> +#include <signal.h>
> +#include <setjmp.h>
>
> #include <rte_log.h>
> #include <rte_memory.h>
> @@ -309,6 +311,21 @@ get_virtual_area(size_t *size, size_t hugepage_sz)
> return addr;
> }
>
> +static sigjmp_buf jmpenv;
> +
> +static void sigbus_handler(int signo __rte_unused)
> +{
> + siglongjmp(jmpenv, 1);
> +}
> +
> +/* Put setjmp into a wrap method to avoid compiling error. Any non-volatile,
> + * non-static local variable in the stack frame calling setjmp might be
> + * clobbered by a call to longjmp.
> + */
> +static int wrap_setjmp(void)
> +{
> + return setjmp(jmpenv);
> +}
> /*
> * Mmap all hugepages of hugepage table: it first open a file in
> * hugetlbfs, then mmap() hugepage_sz data in it. If orig is set, the
> @@ -396,7 +413,7 @@ map_all_hugepages(struct hugepage_file *hugepg_tbl,
> if (fd < 0) {
> RTE_LOG(ERR, EAL, "%s(): open failed: %s\n", __func__,
> strerror(errno));
> - return -1;
> + return i;
> }
>
> /* map the segment, and populate page tables,
> @@ -407,7 +424,7 @@ map_all_hugepages(struct hugepage_file *hugepg_tbl,
> RTE_LOG(ERR, EAL, "%s(): mmap failed: %s\n", __func__,
> strerror(errno));
> close(fd);
> - return -1;
> + return i;
> }
>
> if (orig) {
> @@ -417,12 +434,33 @@ map_all_hugepages(struct hugepage_file *hugepg_tbl,
> hugepg_tbl[i].final_va = virtaddr;
> }
>
> + if (orig && internal_config.huge_trybest) {
> + /* In linux, hugetlb limitations, like cgroup, are
> + * enforced at fault time instead of mmap(), even
> + * with the option of MAP_POPULATE. Kernel will send
> + * a SIGBUS signal. To avoid to be killed, save stack
> + * environment here, if SIGBUS happens, we can jump
> + * back here.
> + */
> + if (wrap_setjmp()) {
> + RTE_LOG(ERR, EAL, "SIGBUS: Cannot mmap more "
> + "hugepages of size %u MB\n",
> + (unsigned)(hugepage_sz / 0x100000));
> + munmap(virtaddr, hugepage_sz);
> + close(fd);
> + unlink(hugepg_tbl[i].filepath);
> + return i;
> + }
> + *(int *)virtaddr = 0;
> + }
> +
> +
> /* set shared flock on the file. */
> if (flock(fd, LOCK_SH | LOCK_NB) == -1) {
> RTE_LOG(ERR, EAL, "%s(): Locking file failed:%s \n",
> __func__, strerror(errno));
> close(fd);
> - return -1;
> + return i;
> }
>
> close(fd);
> @@ -430,7 +468,7 @@ map_all_hugepages(struct hugepage_file *hugepg_tbl,
> vma_addr = (char *)vma_addr + hugepage_sz;
> vma_len -= hugepage_sz;
> }
> - return 0;
> + return i;
> }
>
> #ifdef RTE_EAL_SINGLE_FILE_SEGMENTS
> @@ -1036,6 +1074,33 @@ calc_num_pages_per_socket(uint64_t * memory,
> return total_num_pages;
> }
>
> +static struct sigaction action_old;
> +static int need_recover;
> +
> +static void
> +register_sigbus(void)
> +{
> + sigset_t mask;
> + struct sigaction action;
> +
> + sigemptyset(&mask);
> + sigaddset(&mask, SIGBUS);
> + action.sa_flags = 0;
> + action.sa_mask = mask;
> + action.sa_handler = sigbus_handler;
> +
> + need_recover = !sigaction(SIGBUS, &action, &action_old);
> +}
> +
> +static void
> +recover_sigbus(void)
> +{
> + if (need_recover) {
> + sigaction(SIGBUS, &action_old, NULL);
> + need_recover = 0;
> + }
> +}
> +
> /*
> * Prepare physical memory mapping: fill configuration structure with
> * these infos, return 0 on success.
> @@ -1122,8 +1187,12 @@ rte_eal_hugepage_init(void)
>
> hp_offset = 0; /* where we start the current page size entries */
>
> + if (internal_config.huge_trybest)
> + register_sigbus();
> +
> /* map all hugepages and sort them */
> for (i = 0; i < (int)internal_config.num_hugepage_sizes; i ++){
> + int pages_old, pages_new;
> struct hugepage_info *hpi;
>
> /*
> @@ -1137,10 +1206,24 @@ rte_eal_hugepage_init(void)
> continue;
>
> /* map all hugepages available */
> - if (map_all_hugepages(&tmp_hp[hp_offset], hpi, 1) < 0){
> - RTE_LOG(DEBUG, EAL, "Failed to mmap %u MB hugepages\n",
> - (unsigned)(hpi->hugepage_sz /
> 0x100000));
> - goto fail;
> + pages_old = hpi->num_pages[0];
> + pages_new = map_all_hugepages(&tmp_hp[hp_offset], hpi, 1);
> + if (pages_new < pages_old) {
> + RTE_LOG(DEBUG, EAL,
> + "%d not %d hugepages of size %u MB allocated\n",
> + pages_new, pages_old,
> + (unsigned)(hpi->hugepage_sz / 0x100000));
> + if (internal_config.huge_trybest) {
> + int pages = pages_old - pages_new;
> +
> + internal_config.memory -=
> + hpi->hugepage_sz * pages;
> + nr_hugepages -= pages;
> + hpi->num_pages[0] = pages_new;
> + if (pages_new == 0)
> + continue;
> + } else
> + goto fail;
> }
>
> /* find physical addresses and sockets for each hugepage */
> @@ -1187,6 +1270,9 @@ rte_eal_hugepage_init(void)
> #endif
> }
>
> + if (internal_config.huge_trybest)
> + recover_sigbus();
> +
> #ifdef RTE_EAL_SINGLE_FILE_SEGMENTS
> nr_hugefiles = 0;
> for (i = 0; i < (int) internal_config.num_hugepage_sizes; i++) {
> @@ -1373,6 +1459,8 @@ rte_eal_hugepage_init(void)
> return 0;
>
> fail:
> + if (internal_config.huge_trybest)
> + recover_sigbus();
> free(tmp_hp);
> return -1;
> }
