| Message ID | 1490079006-32495-1-git-send-email-jitendra.kolhe@hpe.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 21/03/2017 07:50, Jitendra Kolhe wrote: > This was spotted by Coverity, in case where sysconf(_SC_NPROCESSORS_ONLN) > fails and returns -1. This results in memset_num_threads getting set to -1. > Which we then pass to g_new0(). > The patch replaces MAX_MEM_PREALLOC_THREAD_COUNT macro with a function call > get_memset_num_threads() to handle sysconf() failure gracefully. In case > sysconf() fails, we fall back to single threaded. > > (Spotted by Coverity, CID 1372465.) > > Signed-off-by: Jitendra Kolhe <jitendra.kolhe@hpe.com> > --- > util/oslib-posix.c | 16 ++++++++++++++-- > 1 file changed, 14 insertions(+), 2 deletions(-) > > diff --git a/util/oslib-posix.c b/util/oslib-posix.c > index 3fe6089..4d9189e 100644 > --- a/util/oslib-posix.c > +++ b/util/oslib-posix.c > @@ -55,7 +55,7 @@ > #include "qemu/error-report.h" > #endif > > -#define MAX_MEM_PREALLOC_THREAD_COUNT (MIN(sysconf(_SC_NPROCESSORS_ONLN), 16)) > +#define MAX_MEM_PREALLOC_THREAD_COUNT 16 > > struct MemsetThread { > char *addr; > @@ -381,6 +381,18 @@ static void *do_touch_pages(void *arg) > return NULL; > } > > +static inline int get_memset_num_threads(int smp_cpus) > +{ > + long host_procs = sysconf(_SC_NPROCESSORS_ONLN); > + int ret = 1; > + > + if (host_procs > 0) { > + ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus); > + } > + /* In case sysconf() fails, we fall back to single threaded */ > + return ret; > +} > + > static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages, > int smp_cpus) > { > @@ -389,7 +401,7 @@ static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages, > int i = 0; > > memset_thread_failed = false; > - memset_num_threads = MIN(smp_cpus, MAX_MEM_PREALLOC_THREAD_COUNT); > + memset_num_threads = get_memset_num_threads(smp_cpus); > memset_thread = g_new0(MemsetThread, memset_num_threads); > numpages_per_thread = (numpages / memset_num_threads); > size_per_thread = (hpagesize * numpages_per_thread); > Queued, thanks. Paolo
diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 3fe6089..4d9189e 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -55,7 +55,7 @@ #include "qemu/error-report.h" #endif -#define MAX_MEM_PREALLOC_THREAD_COUNT (MIN(sysconf(_SC_NPROCESSORS_ONLN), 16)) +#define MAX_MEM_PREALLOC_THREAD_COUNT 16 struct MemsetThread { char *addr; @@ -381,6 +381,18 @@ static void *do_touch_pages(void *arg) return NULL; } +static inline int get_memset_num_threads(int smp_cpus) +{ + long host_procs = sysconf(_SC_NPROCESSORS_ONLN); + int ret = 1; + + if (host_procs > 0) { + ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus); + } + /* In case sysconf() fails, we fall back to single threaded */ + return ret; +} + static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages, int smp_cpus) { @@ -389,7 +401,7 @@ static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages, int i = 0; memset_thread_failed = false; - memset_num_threads = MIN(smp_cpus, MAX_MEM_PREALLOC_THREAD_COUNT); + memset_num_threads = get_memset_num_threads(smp_cpus); memset_thread = g_new0(MemsetThread, memset_num_threads); numpages_per_thread = (numpages / memset_num_threads); size_per_thread = (hpagesize * numpages_per_thread);
This was spotted by Coverity, in case where sysconf(_SC_NPROCESSORS_ONLN) fails and returns -1. This results in memset_num_threads getting set to -1. Which we then pass to g_new0(). The patch replaces MAX_MEM_PREALLOC_THREAD_COUNT macro with a function call get_memset_num_threads() to handle sysconf() failure gracefully. In case sysconf() fails, we fall back to single threaded. (Spotted by Coverity, CID 1372465.) Signed-off-by: Jitendra Kolhe <jitendra.kolhe@hpe.com> --- util/oslib-posix.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)