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util/oslib-posix: Let touch_all_pages() return an error

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Let's prepare touch_all_pages() for returning differing errors. Return
an error from the thread and report the last processed error.

Translate SIGBUS to -EFAULT, as a SIGBUS can mean all different kind of
things (memory error, read error, out of memory). When allocating memory
fails via the current SIGBUS-based mechanism, we'll get:
    os_mem_prealloc: preallocating memory failed: Bad address

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20211217134611.31172-2-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
David Hildenbrand 2021-12-17 14:46:04 +01:00 committed by Michael S. Tsirkin
parent 0a963af3e3
commit 6c427ab926
1 changed files with 16 additions and 12 deletions
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28
util/oslib-posix.c
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@ -84,7 +84,6 @@ typedef struct MemsetThread MemsetThread;
static MemsetThread *memset_thread;
static int memset_num_threads;
static bool memset_thread_failed;
static QemuMutex page_mutex;
static QemuCond page_cond;
@ -452,6 +451,7 @@ static void *do_touch_pages(void *arg)
{
MemsetThread *memset_args = (MemsetThread *)arg;
sigset_t set, oldset;
int ret = 0;
/*
* On Linux, the page faults from the loop below can cause mmap_sem
@ -470,7 +470,7 @@ static void *do_touch_pages(void *arg)
pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
if (sigsetjmp(memset_args->env, 1)) {
memset_thread_failed = true;
ret = -EFAULT;
} else {
char *addr = memset_args->addr;
size_t numpages = memset_args->numpages;
@ -494,7 +494,7 @@ static void *do_touch_pages(void *arg)
}
}
pthread_sigmask(SIG_SETMASK, &oldset, NULL);
return NULL;
return (void *)(uintptr_t)ret;
}
static inline int get_memset_num_threads(int smp_cpus)
@ -509,13 +509,13 @@ static inline int get_memset_num_threads(int smp_cpus)
return ret;
}
static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages,
int smp_cpus)
static int touch_all_pages(char *area, size_t hpagesize, size_t numpages,
int smp_cpus)
{
static gsize initialized = 0;
size_t numpages_per_thread, leftover;
int ret = 0, i = 0;
char *addr = area;
int i = 0;
if (g_once_init_enter(&initialized)) {
qemu_mutex_init(&page_mutex);
@ -523,7 +523,6 @@ static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages,
g_once_init_leave(&initialized, 1);
}
memset_thread_failed = false;
threads_created_flag = false;
memset_num_threads = get_memset_num_threads(smp_cpus);
memset_thread = g_new0(MemsetThread, memset_num_threads);
@ -545,12 +544,16 @@ static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages,
qemu_mutex_unlock(&page_mutex);
for (i = 0; i < memset_num_threads; i++) {
qemu_thread_join(&memset_thread[i].pgthread);
int tmp = (uintptr_t)qemu_thread_join(&memset_thread[i].pgthread);
if (tmp) {
ret = tmp;
}
}
g_free(memset_thread);
memset_thread = NULL;
return memset_thread_failed;
return ret;
}
void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
@ -573,9 +576,10 @@ void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
}
/* touch pages simultaneously */
if (touch_all_pages(area, hpagesize, numpages, smp_cpus)) {
error_setg(errp, "os_mem_prealloc: Insufficient free host memory "
"pages available to allocate guest RAM");
ret = touch_all_pages(area, hpagesize, numpages, smp_cpus);
if (ret) {
error_setg_errno(errp, -ret,
"os_mem_prealloc: preallocating memory failed");
}
ret = sigaction(SIGBUS, &oldact, NULL);