| Message ID | 20210519131916.314184-1-cascardo@canonical.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | mtest06/mmap1: Further limit distant mmap size | expand |
On Wed, May 19, 2021 at 3:22 PM Thadeu Lima de Souza Cascardo <cascardo@canonical.com> wrote: > > Though on recent kernels (starting with 5.2, commit > 8c7829b04c523cdc732cb77f59f03320e09f3386 ("mm: fix false-positive > OVERCOMMIT_GUESS failures"), overcommit accounting allows for allocating up > to MemTotal memory, older kernels have a much more complicated overcommit > guess accounting. > > That leads to mmap failing on small enough systems: > > mmap1.c:205: TBROK: mmap((nil),2088370176,3,34,-1,0) failed: ENOMEM (12) > > Allocating only half of the total memory would generally work on test > systems. > > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Thanks for patch. Acked-by: Jan Stancek <jstancek@redhat.com>
Hi! > > Though on recent kernels (starting with 5.2, commit > > 8c7829b04c523cdc732cb77f59f03320e09f3386 ("mm: fix false-positive > > OVERCOMMIT_GUESS failures"), overcommit accounting allows for allocating up > > to MemTotal memory, older kernels have a much more complicated overcommit > > guess accounting. > > > > That leads to mmap failing on small enough systems: > > > > mmap1.c:205: TBROK: mmap((nil),2088370176,3,34,-1,0) failed: ENOMEM (12) > > > > Allocating only half of the total memory would generally work on test > > systems. > > > > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> > > Thanks for patch. > > Acked-by: Jan Stancek <jstancek@redhat.com> Looks safe enough for the release, as far as I can tell the test shouldn't care at all where we map the block of memory. Jan looks like you originaly wrote the test, do you agree that this should go in now?
Hi! Pushed, thanks.
On Thu, May 20, 2021 at 1:43 PM Cyril Hrubis <chrubis@suse.cz> wrote: > > Hi! > > > Though on recent kernels (starting with 5.2, commit > > > 8c7829b04c523cdc732cb77f59f03320e09f3386 ("mm: fix false-positive > > > OVERCOMMIT_GUESS failures"), overcommit accounting allows for allocating up > > > to MemTotal memory, older kernels have a much more complicated overcommit > > > guess accounting. > > > > > > That leads to mmap failing on small enough systems: > > > > > > mmap1.c:205: TBROK: mmap((nil),2088370176,3,34,-1,0) failed: ENOMEM (12) > > > > > > Allocating only half of the total memory would generally work on test > > > systems. > > > > > > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> > > > > Thanks for patch. > > > > Acked-by: Jan Stancek <jstancek@redhat.com> > > Looks safe enough for the release, as far as I can tell the test > shouldn't care at all where we map the block of memory. > > Jan looks like you originaly wrote the test, do you agree that this > should go in now? That's fine by me. As you said, the change in size doesn't matter that much for the test. > > -- > Cyril Hrubis > chrubis@suse.cz >
diff --git a/testcases/kernel/mem/mtest06/mmap1.c b/testcases/kernel/mem/mtest06/mmap1.c index 56588e1ebaff..10c47c35cb02 100644 --- a/testcases/kernel/mem/mtest06/mmap1.c +++ b/testcases/kernel/mem/mtest06/mmap1.c @@ -186,7 +186,7 @@ static void setup(void) { struct sigaction sigptr; size_t distant_mmap_size; - long mem_total; + size_t mem_total; page_sz = getpagesize(); mem_total = SAFE_READ_MEMINFO("MemTotal:"); @@ -195,7 +195,7 @@ static void setup(void) #ifdef TST_ABI32 distant_mmap_size = 256*1024*1024; #else - distant_mmap_size = (mem_total > 2 * GIGABYTE) ? 2 * GIGABYTE : mem_total; + distant_mmap_size = (mem_total > 4 * GIGABYTE) ? 2 * GIGABYTE : mem_total / 2; #endif /* * Used as hint for mmap thread, so it doesn't interfere
Though on recent kernels (starting with 5.2, commit 8c7829b04c523cdc732cb77f59f03320e09f3386 ("mm: fix false-positive OVERCOMMIT_GUESS failures"), overcommit accounting allows for allocating up to MemTotal memory, older kernels have a much more complicated overcommit guess accounting. That leads to mmap failing on small enough systems: mmap1.c:205: TBROK: mmap((nil),2088370176,3,34,-1,0) failed: ENOMEM (12) Allocating only half of the total memory would generally work on test systems. Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> --- testcases/kernel/mem/mtest06/mmap1.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)