diff options
| -rw-r--r-- | tools/testing/selftests/kvm/Makefile.kvm | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/access_tracking_perf_test.c | 225 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/include/lru_gen_util.h | 51 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/lib/lru_gen_util.c | 387 |
4 files changed, 638 insertions, 26 deletions
diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm index 410f2920a638..13c1db0de2a7 100644 --- a/tools/testing/selftests/kvm/Makefile.kvm +++ b/tools/testing/selftests/kvm/Makefile.kvm @@ -8,6 +8,7 @@ LIBKVM += lib/elf.c LIBKVM += lib/guest_modes.c LIBKVM += lib/io.c LIBKVM += lib/kvm_util.c +LIBKVM += lib/lru_gen_util.c LIBKVM += lib/memstress.c LIBKVM += lib/guest_sprintf.c LIBKVM += lib/rbtree.c diff --git a/tools/testing/selftests/kvm/access_tracking_perf_test.c b/tools/testing/selftests/kvm/access_tracking_perf_test.c index f273e4a33b11..da7196fd1b23 100644 --- a/tools/testing/selftests/kvm/access_tracking_perf_test.c +++ b/tools/testing/selftests/kvm/access_tracking_perf_test.c @@ -7,9 +7,11 @@ * This test measures the performance effects of KVM's access tracking. * Access tracking is driven by the MMU notifiers test_young, clear_young, and * clear_flush_young. These notifiers do not have a direct userspace API, - * however the clear_young notifier can be triggered by marking a pages as idle - * in /sys/kernel/mm/page_idle/bitmap. This test leverages that mechanism to - * enable access tracking on guest memory. + * however the clear_young notifier can be triggered either by + * 1. marking a pages as idle in /sys/kernel/mm/page_idle/bitmap OR + * 2. adding a new MGLRU generation using the lru_gen debugfs file. + * This test leverages page_idle to enable access tracking on guest memory + * unless MGLRU is enabled, in which case MGLRU is used. * * To measure performance this test runs a VM with a configurable number of * vCPUs that each touch every page in disjoint regions of memory. Performance @@ -17,10 +19,11 @@ * predefined region. * * Note that a deterministic correctness test of access tracking is not possible - * by using page_idle as it exists today. This is for a few reasons: + * by using page_idle or MGLRU aging as it exists today. This is for a few + * reasons: * - * 1. page_idle only issues clear_young notifiers, which lack a TLB flush. This - * means subsequent guest accesses are not guaranteed to see page table + * 1. page_idle and MGLRU only issue clear_young notifiers, which lack a TLB flush. + * This means subsequent guest accesses are not guaranteed to see page table * updates made by KVM until some time in the future. * * 2. page_idle only operates on LRU pages. Newly allocated pages are not @@ -48,9 +51,17 @@ #include "guest_modes.h" #include "processor.h" +#include "cgroup_util.h" +#include "lru_gen_util.h" + +static const char *TEST_MEMCG_NAME = "access_tracking_perf_test"; + /* Global variable used to synchronize all of the vCPU threads. */ static int iteration; +/* The cgroup memory controller root. Needed for lru_gen-based aging. */ +char cgroup_root[PATH_MAX]; + /* Defines what vCPU threads should do during a given iteration. */ static enum { /* Run the vCPU to access all its memory. */ @@ -75,6 +86,15 @@ static bool overlap_memory_access; */ static int idle_pages_warn_only = -1; +/* Whether or not to use MGLRU instead of page_idle for access tracking */ +static bool use_lru_gen; + +/* Total number of pages to expect in the memcg after touching everything */ +static long test_pages; + +/* Last generation we found the pages in */ +static int lru_gen_last_gen = -1; + struct test_params { /* The backing source for the region of memory. */ enum vm_mem_backing_src_type backing_src; @@ -133,8 +153,24 @@ static void mark_page_idle(int page_idle_fd, uint64_t pfn) "Set page_idle bits for PFN 0x%" PRIx64, pfn); } -static void mark_vcpu_memory_idle(struct kvm_vm *vm, - struct memstress_vcpu_args *vcpu_args) +static void too_many_idle_pages(long idle_pages, long total_pages, int vcpu_idx) +{ + char prefix[18] = {}; + + if (vcpu_idx >= 0) + snprintf(prefix, 18, "vCPU%d: ", vcpu_idx); + + TEST_ASSERT(idle_pages_warn_only, + "%sToo many pages still idle (%lu out of %lu)", + prefix, idle_pages, total_pages); + + printf("WARNING: %sToo many pages still idle (%lu out of %lu), " + "this will affect performance results.\n", + prefix, idle_pages, total_pages); +} + +static void pageidle_mark_vcpu_memory_idle(struct kvm_vm *vm, + struct memstress_vcpu_args *vcpu_args) { int vcpu_idx = vcpu_args->vcpu_idx; uint64_t base_gva = vcpu_args->gva; @@ -188,20 +224,78 @@ static void mark_vcpu_memory_idle(struct kvm_vm *vm, * access tracking but low enough as to not make the test too brittle * over time and across architectures. */ - if (still_idle >= pages / 10) { - TEST_ASSERT(idle_pages_warn_only, - "vCPU%d: Too many pages still idle (%lu out of %lu)", - vcpu_idx, still_idle, pages); - - printf("WARNING: vCPU%d: Too many pages still idle (%lu out of %lu), " - "this will affect performance results.\n", - vcpu_idx, still_idle, pages); - } + if (still_idle >= pages / 10) + too_many_idle_pages(still_idle, pages, + overlap_memory_access ? -1 : vcpu_idx); close(page_idle_fd); close(pagemap_fd); } +int find_generation(struct memcg_stats *stats, long total_pages) +{ + /* + * For finding the generation that contains our pages, use the same + * 90% threshold that page_idle uses. + */ + int gen = lru_gen_find_generation(stats, total_pages * 9 / 10); + + if (gen >= 0) + return gen; + + if (!idle_pages_warn_only) { + TEST_FAIL("Could not find a generation with 90%% of guest memory (%ld pages).", + total_pages * 9 / 10); + return gen; + } + + /* + * We couldn't find a generation with 90% of guest memory, which can + * happen if access tracking is unreliable. Simply look for a majority + * of pages. + */ + puts("WARNING: Couldn't find a generation with 90% of guest memory. " + "Performance results may not be accurate."); + gen = lru_gen_find_generation(stats, total_pages / 2); + TEST_ASSERT(gen >= 0, + "Could not find a generation with 50%% of guest memory (%ld pages).", + total_pages / 2); + return gen; +} + +static void lru_gen_mark_memory_idle(struct kvm_vm *vm) +{ + struct timespec ts_start; + struct timespec ts_elapsed; + struct memcg_stats stats; + int new_gen; + + /* Make a new generation */ + clock_gettime(CLOCK_MONOTONIC, &ts_start); + lru_gen_do_aging(&stats, TEST_MEMCG_NAME); + ts_elapsed = timespec_elapsed(ts_start); + + /* Check the generation again */ + new_gen = find_generation(&stats, test_pages); + + /* + * This function should only be invoked with newly-accessed pages, + * so pages should always move to a newer generation. + */ + if (new_gen <= lru_gen_last_gen) { + /* We did not move to a newer generation. */ + long idle_pages = lru_gen_sum_memcg_stats_for_gen(lru_gen_last_gen, + &stats); + + too_many_idle_pages(min_t(long, idle_pages, test_pages), + test_pages, -1); + } + pr_info("%-30s: %ld.%09lds\n", + "Mark memory idle (lru_gen)", ts_elapsed.tv_sec, + ts_elapsed.tv_nsec); + lru_gen_last_gen = new_gen; +} + static void assert_ucall(struct kvm_vcpu *vcpu, uint64_t expected_ucall) { struct ucall uc; @@ -241,7 +335,7 @@ static void vcpu_thread_main(struct memstress_vcpu_args *vcpu_args) assert_ucall(vcpu, UCALL_SYNC); break; case ITERATION_MARK_IDLE: - mark_vcpu_memory_idle(vm, vcpu_args); + pageidle_mark_vcpu_memory_idle(vm, vcpu_args); break; } @@ -293,15 +387,18 @@ static void access_memory(struct kvm_vm *vm, int nr_vcpus, static void mark_memory_idle(struct kvm_vm *vm, int nr_vcpus) { + if (use_lru_gen) + return lru_gen_mark_memory_idle(vm); + /* * Even though this parallelizes the work across vCPUs, this is still a * very slow operation because page_idle forces the test to mark one pfn - * at a time and the clear_young notifier serializes on the KVM MMU + * at a time and the clear_young notifier may serialize on the KVM MMU * lock. */ pr_debug("Marking VM memory idle (slow)...\n"); iteration_work = ITERATION_MARK_IDLE; - run_iteration(vm, nr_vcpus, "Mark memory idle"); + run_iteration(vm, nr_vcpus, "Mark memory idle (page_idle)"); } static void run_test(enum vm_guest_mode mode, void *arg) @@ -313,11 +410,38 @@ static void run_test(enum vm_guest_mode mode, void *arg) vm = memstress_create_vm(mode, nr_vcpus, params->vcpu_memory_bytes, 1, params->backing_src, !overlap_memory_access); + /* + * If guest_page_size is larger than the host's page size, the + * guest (memstress) will only fault in a subset of the host's pages. + */ + test_pages = params->nr_vcpus * params->vcpu_memory_bytes / + max(memstress_args.guest_page_size, + (uint64_t)getpagesize()); + memstress_start_vcpu_threads(nr_vcpus, vcpu_thread_main); pr_info("\n"); access_memory(vm, nr_vcpus, ACCESS_WRITE, "Populating memory"); + if (use_lru_gen) { + struct memcg_stats stats; + + /* + * Do a page table scan now. Following initial population, aging + * may not cause the pages to move to a newer generation. Do + * an aging pass now so that future aging passes always move + * pages to a newer generation. + */ + printf("Initial aging pass (lru_gen)\n"); + lru_gen_do_aging(&stats, TEST_MEMCG_NAME); + TEST_ASSERT(lru_gen_sum_memcg_stats(&stats) >= test_pages, + "Not all pages accounted for (looking for %ld). " + "Was the memcg set up correctly?", test_pages); + access_memory(vm, nr_vcpus, ACCESS_WRITE, "Re-populating memory"); + lru_gen_read_memcg_stats(&stats, TEST_MEMCG_NAME); + lru_gen_last_gen = find_generation(&stats, test_pages); + } + /* As a control, read and write to the populated memory first. */ access_memory(vm, nr_vcpus, ACCESS_WRITE, "Writing to populated memory"); access_memory(vm, nr_vcpus, ACCESS_READ, "Reading from populated memory"); @@ -354,7 +478,12 @@ static int access_tracking_unreliable(void) puts("Skipping idle page count sanity check, because NUMA balancing is enabled"); return 1; } + return 0; +} +static int run_test_for_each_guest_mode(const char *cgroup, void *arg) +{ + for_each_guest_mode(run_test, arg); return 0; } @@ -383,6 +512,11 @@ static void help(char *name) exit(0); } +void destroy_cgroup(char *cg) +{ + printf("Destroying cgroup: %s\n", cg); +} + int main(int argc, char *argv[]) { struct test_params params = { @@ -390,6 +524,7 @@ int main(int argc, char *argv[]) .vcpu_memory_bytes = DEFAULT_PER_VCPU_MEM_SIZE, .nr_vcpus = 1, }; + char *new_cg = NULL; int page_idle_fd; int opt; @@ -424,15 +559,53 @@ int main(int argc, char *argv[]) } } - page_idle_fd = open("/sys/kernel/mm/page_idle/bitmap", O_RDWR); - __TEST_REQUIRE(page_idle_fd >= 0, - "CONFIG_IDLE_PAGE_TRACKING is not enabled"); - close(page_idle_fd); - if (idle_pages_warn_only == -1) idle_pages_warn_only = access_tracking_unreliable(); - for_each_guest_mode(run_test, ¶ms); + if (lru_gen_usable()) { + bool cg_created = true; + int ret; + + puts("Using lru_gen for aging"); + use_lru_gen = true; + + if (cg_find_controller_root(cgroup_root, sizeof(cgroup_root), "memory")) + ksft_exit_skip("Cannot find memory cgroup controller\n"); + + new_cg = cg_name(cgroup_root, TEST_MEMCG_NAME); + printf("Creating cgroup: %s\n", new_cg); + if (cg_create(new_cg)) { + if (errno == EEXIST) { + printf("Found existing cgroup"); + cg_created = false; + } else { + ksft_exit_skip("could not create new cgroup: %s\n", new_cg); + } + } + + /* + * This will fork off a new process to run the test within + * a new memcg, so we need to properly propagate the return + * value up. + */ + ret = cg_run(new_cg, &run_test_for_each_guest_mode, ¶ms); + if (cg_created) + cg_destroy(new_cg); + if (ret < 0) + TEST_FAIL("child did not spawn or was abnormally killed"); + if (ret) + return ret; + } else { + page_idle_fd = open("/sys/kernel/mm/page_idle/bitmap", O_RDWR); + __TEST_REQUIRE(page_idle_fd >= 0, + "Couldn't open /sys/kernel/mm/page_idle/bitmap. " + "Is CONFIG_IDLE_PAGE_TRACKING enabled?"); + + close(page_idle_fd); + + puts("Using page_idle for aging"); + run_test_for_each_guest_mode(NULL, ¶ms); + } return 0; } diff --git a/tools/testing/selftests/kvm/include/lru_gen_util.h b/tools/testing/selftests/kvm/include/lru_gen_util.h new file mode 100644 index 000000000000..d32ff5d8ffd0 --- /dev/null +++ b/tools/testing/selftests/kvm/include/lru_gen_util.h @@ -0,0 +1,51 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Tools for integrating with lru_gen, like parsing the lru_gen debugfs output. + * + * Copyright (C) 2025, Google LLC. + */ +#ifndef SELFTEST_KVM_LRU_GEN_UTIL_H +#define SELFTEST_KVM_LRU_GEN_UTIL_H + +#include <inttypes.h> +#include <limits.h> +#include <stdlib.h> + +#include "test_util.h" + +#define MAX_NR_GENS 16 /* MAX_NR_GENS in include/linux/mmzone.h */ +#define MAX_NR_NODES 4 /* Maximum number of nodes supported by the test */ + +#define LRU_GEN_DEBUGFS "/sys/kernel/debug/lru_gen" +#define LRU_GEN_ENABLED_PATH "/sys/kernel/mm/lru_gen/enabled" +#define LRU_GEN_ENABLED 1 +#define LRU_GEN_MM_WALK 2 + +struct generation_stats { + int gen; + long age_ms; + long nr_anon; + long nr_file; +}; + +struct node_stats { + int node; + int nr_gens; /* Number of populated gens entries. */ + struct generation_stats gens[MAX_NR_GENS]; +}; + +struct memcg_stats { + unsigned long memcg_id; + int nr_nodes; /* Number of populated nodes entries. */ + struct node_stats nodes[MAX_NR_NODES]; +}; + +void lru_gen_read_memcg_stats(struct memcg_stats *stats, const char *memcg); +long lru_gen_sum_memcg_stats(const struct memcg_stats *stats); +long lru_gen_sum_memcg_stats_for_gen(int gen, const struct memcg_stats *stats); +void lru_gen_do_aging(struct memcg_stats *stats, const char *memcg); +int lru_gen_find_generation(const struct memcg_stats *stats, + unsigned long total_pages); +bool lru_gen_usable(void); + +#endif /* SELFTEST_KVM_LRU_GEN_UTIL_H */ diff --git a/tools/testing/selftests/kvm/lib/lru_gen_util.c b/tools/testing/selftests/kvm/lib/lru_gen_util.c new file mode 100644 index 000000000000..46a14fd63d9e --- /dev/null +++ b/tools/testing/selftests/kvm/lib/lru_gen_util.c @@ -0,0 +1,387 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2025, Google LLC. + */ + +#include <time.h> + +#include "lru_gen_util.h" + +/* + * Tracks state while we parse memcg lru_gen stats. The file we're parsing is + * structured like this (some extra whitespace elided): + * + * memcg (id) (path) + * node (id) + * (gen_nr) (age_in_ms) (nr_anon_pages) (nr_file_pages) + */ +struct memcg_stats_parse_context { + bool consumed; /* Whether or not this line was consumed */ + /* Next parse handler to invoke */ + void (*next_handler)(struct memcg_stats *stats, + struct memcg_stats_parse_context *ctx, + char *line); + int current_node_idx; /* Current index in nodes array */ + const char *name; /* The name of the memcg we're looking for */ +}; + +static void memcg_stats_handle_searching(struct memcg_stats *stats, + struct memcg_stats_parse_context *ctx, + char *line); +static void memcg_stats_handle_in_memcg(struct memcg_stats *stats, + struct memcg_stats_parse_context *ctx, + char *line); +static void memcg_stats_handle_in_node(struct memcg_stats *stats, + struct memcg_stats_parse_context *ctx, + char *line); + +struct split_iterator { + char *str; + char *save; +}; + +static char *split_next(struct split_iterator *it) +{ + char *ret = strtok_r(it->str, " \t\n\r", &it->save); + + it->str = NULL; + return ret; +} + +static void memcg_stats_handle_searching(struct memcg_stats *stats, + struct memcg_stats_parse_context *ctx, + char *line) +{ + struct split_iterator it = { .str = line }; + char *prefix = split_next(&it); + char *memcg_id = split_next(&it); + char *memcg_name = split_next(&it); + char *end; + + ctx->consumed = true; + + if (!prefix || strcmp("memcg", prefix)) + return; /* Not a memcg line (maybe empty), skip */ + + TEST_ASSERT(memcg_id && memcg_name, + "malformed memcg line; no memcg id or memcg_name"); + + if (strcmp(memcg_name + 1, ctx->name)) + return; /* Wrong memcg, skip */ + + /* Found it! */ + + stats->memcg_id = strtoul(memcg_id, &end, 10); + TEST_ASSERT(*end == '\0', "malformed memcg id '%s'", memcg_id); + if (!stats->memcg_id) + return; /* Removed memcg? */ + + ctx->next_handler = memcg_stats_handle_in_memcg; +} + +static void memcg_stats_handle_in_memcg(struct memcg_stats *stats, + struct memcg_stats_parse_context *ctx, + char *line) +{ + struct split_iterator it = { .str = line }; + char *prefix = split_next(&it); + char *id = split_next(&it); + long found_node_id; + char *end; + + ctx->consumed = true; + ctx->current_node_idx = -1; + + if (!prefix) + return; /* Skip empty lines */ + + if (!strcmp("memcg", prefix)) { + /* Memcg done, found next one; stop. */ + ctx->next_handler = NULL; + return; + } else if (strcmp("node", prefix)) + TEST_ASSERT(false, "found malformed line after 'memcg ...'," + "token: '%s'", prefix); + + /* At this point we know we have a node line. Parse the ID. */ + + TEST_ASSERT(id, "malformed node line; no node id"); + + found_node_id = strtol(id, &end, 10); + TEST_ASSERT(*end == '\0', "malformed node id '%s'", id); + + ctx->current_node_idx = stats->nr_nodes++; + TEST_ASSERT(ctx->current_node_idx < MAX_NR_NODES, + "memcg has stats for too many nodes, max is %d", + MAX_NR_NODES); + stats->nodes[ctx->current_node_idx].node = found_node_id; + + ctx->next_handler = memcg_stats_handle_in_node; +} + +static void memcg_stats_handle_in_node(struct memcg_stats *stats, + struct memcg_stats_parse_context *ctx, + char *line) +{ + char *my_line = strdup(line); + struct split_iterator it = { .str = my_line }; + char *gen, *age, *nr_anon, *nr_file; + struct node_stats *node_stats; + struct generation_stats *gen_stats; + char *end; + + TEST_ASSERT(it.str, "failed to copy input line"); + + gen = split_next(&it); + + if (!gen) + goto out_consume; /* Skip empty lines */ + + if (!strcmp("memcg", gen) || !strcmp("node", gen)) { + /* + * Reached next memcg or node section. Don't consume, let the + * other handler deal with this. + */ + ctx->next_handler = memcg_stats_handle_in_memcg; + goto out; + } + + node_stats = &stats->nodes[ctx->current_node_idx]; + TEST_ASSERT(node_stats->nr_gens < MAX_NR_GENS, + "found too many generation lines; max is %d", + MAX_NR_GENS); + gen_stats = &node_stats->gens[node_stats->nr_gens++]; + + age = split_next(&it); + nr_anon = split_next(&it); + nr_file = split_next(&it); + + TEST_ASSERT(age && nr_anon && nr_file, + "malformed generation line; not enough tokens"); + + gen_stats->gen = (int)strtol(gen, &end, 10); + TEST_ASSERT(*end == '\0', "malformed generation number '%s'", gen); + + gen_stats->age_ms = strtol(age, &end, 10); + TEST_ASSERT(*end == '\0', "malformed generation age '%s'", age); + + gen_stats->nr_anon = strtol(nr_anon, &end, 10); + TEST_ASSERT(*end == '\0', "malformed anonymous page count '%s'", + nr_anon); + + gen_stats->nr_file = strtol(nr_file, &end, 10); + TEST_ASSERT(*end == '\0', "malformed file page count '%s'", nr_file); + +out_consume: + ctx->consumed = true; +out: + free(my_line); +} + +static void print_memcg_stats(const struct memcg_stats *stats, const char *name) +{ + int node, gen; + + pr_debug("stats for memcg %s (id %lu):\n", name, stats->memcg_id); + for (node = 0; node < stats->nr_nodes; ++node) { + pr_debug("\tnode %d\n", stats->nodes[node].node); + for (gen = 0; gen < stats->nodes[node].nr_gens; ++gen) { + const struct generation_stats *gstats = + &stats->nodes[node].gens[gen]; + + pr_debug("\t\tgen %d\tage_ms %ld" + "\tnr_anon %ld\tnr_file %ld\n", + gstats->gen, gstats->age_ms, gstats->nr_anon, + gstats->nr_file); + } + } +} + +/* Re-read lru_gen debugfs information for @memcg into @stats. */ +void lru_gen_read_memcg_stats(struct memcg_stats *stats, const char *memcg) +{ + FILE *f; + ssize_t read = 0; + char *line = NULL; + size_t bufsz; + struct memcg_stats_parse_context ctx = { + .next_handler = memcg_stats_handle_searching, + .name = memcg, + }; + + memset(stats, 0, sizeof(struct memcg_stats)); + + f = fopen(LRU_GEN_DEBUGFS, "r"); + TEST_ASSERT(f, "fopen(%s) failed", LRU_GEN_DEBUGFS); + + while (ctx.next_handler && (read = getline(&line, &bufsz, f)) > 0) { + ctx.consumed = false; + + do { + ctx.next_handler(stats, &ctx, line); + if (!ctx.next_handler) + break; + } while (!ctx.consumed); + } + + if (read < 0 && !feof(f)) + TEST_ASSERT(false, "getline(%s) failed", LRU_GEN_DEBUGFS); + + TEST_ASSERT(stats->memcg_id > 0, "Couldn't find memcg: %s\n" + "Did the memcg get created in the proper mount?", + memcg); + if (line) + free(line); + TEST_ASSERT(!fclose(f), "fclose(%s) failed", LRU_GEN_DEBUGFS); + + print_memcg_stats(stats, memcg); +} + +/* + * Find all pages tracked by lru_gen for this memcg in generation @target_gen. + * + * If @target_gen is negative, look for all generations. + */ +long lru_gen_sum_memcg_stats_for_gen(int target_gen, + const struct memcg_stats *stats) +{ + int node, gen; + long total_nr = 0; + + for (node = 0; node < stats->nr_nodes; ++node) { + const struct node_stats *node_stats = &stats->nodes[node]; + + for (gen = 0; gen < node_stats->nr_gens; ++gen) { + const struct generation_stats *gen_stats = + &node_stats->gens[gen]; + + if (target_gen >= 0 && gen_stats->gen != target_gen) + continue; + + total_nr += gen_stats->nr_anon + gen_stats->nr_file; + } + } + + return total_nr; +} + +/* Find all pages tracked by lru_gen for this memcg. */ +long lru_gen_sum_memcg_stats(const struct memcg_stats *stats) +{ + return lru_gen_sum_memcg_stats_for_gen(-1, stats); +} + +/* + * If lru_gen aging should force page table scanning. + * + * If you want to set this to false, you will need to do eviction + * before doing extra aging passes. + */ +static const bool force_scan = true; + +static void run_aging_impl(unsigned long memcg_id, int node_id, int max_gen) +{ + FILE *f = fopen(LRU_GEN_DEBUGFS, "w"); + char *command; + size_t sz; + + TEST_ASSERT(f, "fopen(%s) failed", LRU_GEN_DEBUGFS); + sz = asprintf(&command, "+ %lu %d %d 1 %d\n", + memcg_id, node_id, max_gen, force_scan); + TEST_ASSERT(sz > 0, "creating aging command failed"); + + pr_debug("Running aging command: %s", command); + if (fwrite(command, sizeof(char), sz, f) < sz) { + TEST_ASSERT(false, "writing aging command %s to %s failed", + command, LRU_GEN_DEBUGFS); + } + + TEST_ASSERT(!fclose(f), "fclose(%s) failed", LRU_GEN_DEBUGFS); +} + +void lru_gen_do_aging(struct memcg_stats *stats, const char *memcg) +{ + int node, gen; + + pr_debug("lru_gen: invoking aging...\n"); + + /* Must read memcg stats to construct the proper aging command. */ + lru_gen_read_memcg_stats(stats, memcg); + + for (node = 0; node < stats->nr_nodes; ++node) { + int max_gen = 0; + + for (gen = 0; gen < stats->nodes[node].nr_gens; ++gen) { + int this_gen = stats->nodes[node].gens[gen].gen; + + max_gen = max_gen > this_gen ? max_gen : this_gen; + } + + run_aging_impl(stats->memcg_id, stats->nodes[node].node, + max_gen); + } + + /* Re-read so callers get updated information */ + lru_gen_read_memcg_stats(stats, memcg); +} + +/* + * Find which generation contains at least @pages pages, assuming that + * such a generation exists. + */ +int lru_gen_find_generation(const struct memcg_stats *stats, + unsigned long pages) +{ + int node, gen, gen_idx, min_gen = INT_MAX, max_gen = -1; + + for (node = 0; node < stats->nr_nodes; ++node) + for (gen_idx = 0; gen_idx < stats->nodes[node].nr_gens; + ++gen_idx) { + gen = stats->nodes[node].gens[gen_idx].gen; + max_gen = gen > max_gen ? gen : max_gen; + min_gen = gen < min_gen ? gen : min_gen; + } + + for (gen = min_gen; gen <= max_gen; ++gen) + /* See if this generation has enough pages. */ + if (lru_gen_sum_memcg_stats_for_gen(gen, stats) > pages) + return gen; + + return -1; +} + +bool lru_gen_usable(void) +{ + long required_features = LRU_GEN_ENABLED | LRU_GEN_MM_WALK; + int lru_gen_fd, lru_gen_debug_fd; + char mglru_feature_str[8] = {}; + long mglru_features; + + lru_gen_fd = open(LRU_GEN_ENABLED_PATH, O_RDONLY); + if (lru_gen_fd < 0) { + puts("lru_gen: Could not open " LRU_GEN_ENABLED_PATH); + return false; + } + if (read(lru_gen_fd, &mglru_feature_str, 7) < 7) { + puts("lru_gen: Could not read from " LRU_GEN_ENABLED_PATH); + close(lru_gen_fd); + return false; + } + close(lru_gen_fd); + + mglru_features = strtol(mglru_feature_str, NULL, 16); + if ((mglru_features & required_features) != required_features) { + printf("lru_gen: missing features, got: 0x%lx, expected: 0x%lx\n", + mglru_features, required_features); + printf("lru_gen: Try 'echo 0x%lx > /sys/kernel/mm/lru_gen/enabled'\n", + required_features); + return false; + } + + lru_gen_debug_fd = open(LRU_GEN_DEBUGFS, O_RDWR); + __TEST_REQUIRE(lru_gen_debug_fd >= 0, + "lru_gen: Could not open " LRU_GEN_DEBUGFS ", " + "but lru_gen is enabled, so cannot use page_idle."); + close(lru_gen_debug_fd); + return true; +} |