| Message ID | 20180703085602.7189-1-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 03/07/2018 09:56, Chris Wilson wrote: > sysinfo() doesn't include all reclaimable memory. In particular it > excludes the majority of global_node_page_state(NR_FILE_PAGES), > reclaimable pages that are a copy of on-disk files It seems the only way > to obtain this counter is by parsing /proc/meminfo. For comparison, > check vm_enough_memory() which includes NR_FILE_PAGES as available > (sadly there's no way to call vm_enough_memory() directly either!) > > v2: Pay attention to what one writes. > v3: Trim off redundant space, and warn if the requested tags do not > match the layout of /proc/meminfo. > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> > --- > lib/intel_os.c | 44 +++++++++++++++++++++++++++++++++++++++----- > 1 file changed, 39 insertions(+), 5 deletions(-) > > diff --git a/lib/intel_os.c b/lib/intel_os.c > index 885ffdcec..29a27272e 100644 > --- a/lib/intel_os.c > +++ b/lib/intel_os.c > @@ -84,6 +84,19 @@ intel_get_total_ram_mb(void) > return retval / (1024*1024); > } > > +static uint64_t get_meminfo(const char *info, const char *tag) > +{ > + const char *str; > + unsigned long val; > + > + str = strstr(info, tag); > + if (str && sscanf(str + strlen(tag), " %lu", &val) == 1) > + return (uint64_t)val << 10; > + > + igt_warn("Unrecognised /proc/meminfo field: '%s'\n", tag); > + return 0; > +} > + > /** > * intel_get_avail_ram_mb: > * > @@ -96,17 +109,38 @@ intel_get_avail_ram_mb(void) > uint64_t retval; > > #ifdef HAVE_STRUCT_SYSINFO_TOTALRAM /* Linux */ > - struct sysinfo sysinf; > + char *info; > int fd; > > fd = drm_open_driver(DRIVER_INTEL); > intel_purge_vm_caches(fd); > close(fd); > > - igt_assert(sysinfo(&sysinf) == 0); > - retval = sysinf.freeram; > - retval += min(sysinf.freeswap, sysinf.bufferram); > - retval *= sysinf.mem_unit; > + fd = open("/proc", O_RDONLY); > + info = igt_sysfs_get(fd, "meminfo"); > + close(fd); > + > + if (info) { > + retval = get_meminfo(info, "MemAvailable:"); > + retval += get_meminfo(info, "Buffers:"); > + /* > + * Include the file+swap cache as "available" for the test. > + * We believe that we can revoke these pages back to their > + * on disk counterpart, with no loss of functionality while > + * the test runs using those pages for ourselves without the > + * test itself being swapped to disk. > + */ > + retval += get_meminfo(info, "Cached:"); > + retval += get_meminfo(info, "SwapCached:"); > + free(info); > + } else { > + struct sysinfo sysinf; > + > + igt_assert(sysinfo(&sysinf) == 0); > + retval = sysinf.freeram; > + retval += min(sysinf.freeswap, sysinf.bufferram); > + retval *= sysinf.mem_unit; > + } > #elif defined(_SC_PAGESIZE) && defined(_SC_AVPHYS_PAGES) /* Solaris */ > long pagesize, npages; > > Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Regards, Tvrtko
diff --git a/lib/intel_os.c b/lib/intel_os.c index 885ffdcec..29a27272e 100644 --- a/lib/intel_os.c +++ b/lib/intel_os.c @@ -84,6 +84,19 @@ intel_get_total_ram_mb(void) return retval / (1024*1024); } +static uint64_t get_meminfo(const char *info, const char *tag) +{ + const char *str; + unsigned long val; + + str = strstr(info, tag); + if (str && sscanf(str + strlen(tag), " %lu", &val) == 1) + return (uint64_t)val << 10; + + igt_warn("Unrecognised /proc/meminfo field: '%s'\n", tag); + return 0; +} + /** * intel_get_avail_ram_mb: * @@ -96,17 +109,38 @@ intel_get_avail_ram_mb(void) uint64_t retval; #ifdef HAVE_STRUCT_SYSINFO_TOTALRAM /* Linux */ - struct sysinfo sysinf; + char *info; int fd; fd = drm_open_driver(DRIVER_INTEL); intel_purge_vm_caches(fd); close(fd); - igt_assert(sysinfo(&sysinf) == 0); - retval = sysinf.freeram; - retval += min(sysinf.freeswap, sysinf.bufferram); - retval *= sysinf.mem_unit; + fd = open("/proc", O_RDONLY); + info = igt_sysfs_get(fd, "meminfo"); + close(fd); + + if (info) { + retval = get_meminfo(info, "MemAvailable:"); + retval += get_meminfo(info, "Buffers:"); + /* + * Include the file+swap cache as "available" for the test. + * We believe that we can revoke these pages back to their + * on disk counterpart, with no loss of functionality while + * the test runs using those pages for ourselves without the + * test itself being swapped to disk. + */ + retval += get_meminfo(info, "Cached:"); + retval += get_meminfo(info, "SwapCached:"); + free(info); + } else { + struct sysinfo sysinf; + + igt_assert(sysinfo(&sysinf) == 0); + retval = sysinf.freeram; + retval += min(sysinf.freeswap, sysinf.bufferram); + retval *= sysinf.mem_unit; + } #elif defined(_SC_PAGESIZE) && defined(_SC_AVPHYS_PAGES) /* Solaris */ long pagesize, npages;
sysinfo() doesn't include all reclaimable memory. In particular it excludes the majority of global_node_page_state(NR_FILE_PAGES), reclaimable pages that are a copy of on-disk files It seems the only way to obtain this counter is by parsing /proc/meminfo. For comparison, check vm_enough_memory() which includes NR_FILE_PAGES as available (sadly there's no way to call vm_enough_memory() directly either!) v2: Pay attention to what one writes. v3: Trim off redundant space, and warn if the requested tags do not match the layout of /proc/meminfo. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> --- lib/intel_os.c | 44 +++++++++++++++++++++++++++++++++++++++----- 1 file changed, 39 insertions(+), 5 deletions(-)