58 lines
2.0 KiB
Diff
58 lines
2.0 KiB
Diff
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From b6c45f5ea5d1a379ac0a507cf59345c573b27cc8 Mon Sep 17 00:00:00 2001
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From: Chuan Zheng <zhengchuan@huawei.com>
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Date: Wed, 9 Feb 2022 14:21:39 +0800
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Subject: [PATCH] oslib-posix: optimise vm startup time for 1G hugepage
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It takes quit a long time to clear 1G-hugepage, which makes glibc
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pthread_create quit slow.
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Create touch_pages threads in advance, and then handle the touch_pages
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callback. Only read lock is held here.
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---
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util/oslib-posix.c | 9 ++++++++-
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1 file changed, 8 insertions(+), 1 deletion(-)
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diff --git a/util/oslib-posix.c b/util/oslib-posix.c
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index e86fd64e09..9ca3fee2b8 100644
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--- a/util/oslib-posix.c
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+++ b/util/oslib-posix.c
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@@ -88,6 +88,8 @@ static QemuMutex sigbus_mutex;
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static QemuMutex page_mutex;
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static QemuCond page_cond;
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+static int started_num_threads;
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+
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int qemu_get_thread_id(void)
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{
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#if defined(__linux__)
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@@ -344,6 +346,10 @@ static void *do_touch_pages(void *arg)
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}
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qemu_mutex_unlock(&page_mutex);
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+ while (started_num_threads != memset_args->context.num_threads) {
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+ smp_mb();
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+ }
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+
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/* unblock SIGBUS */
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sigemptyset(&set);
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sigaddset(&set, SIGBUS);
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@@ -448,7 +454,7 @@ static int touch_all_pages(char *area, size_t hpagesize, size_t numpages,
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context.threads = g_new0(MemsetThread, context.num_threads);
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numpages_per_thread = numpages / context.num_threads;
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leftover = numpages % context.num_threads;
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- for (i = 0; i < context.num_threads; i++) {
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+ for (i = 0, started_num_threads = 0; i < context.num_threads; i++) {
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context.threads[i].addr = addr;
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context.threads[i].numpages = numpages_per_thread + (i < leftover);
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context.threads[i].hpagesize = hpagesize;
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@@ -464,6 +470,7 @@ static int touch_all_pages(char *area, size_t hpagesize, size_t numpages,
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QEMU_THREAD_JOINABLE);
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}
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addr += context.threads[i].numpages * hpagesize;
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+ started_num_threads++;
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}
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if (!use_madv_populate_write) {
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--
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2.27.0
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