nr_hugepages is not set to zero because the file offset has not been reset after read(). Fix that using lseek().
Fixes: bd67d5c15cc1 ("Test compaction of mlocked memory") Cc: stable@vger.kernel.org Signed-off-by: Dev Jain dev.jain@arm.com --- Merge dependency: https://lore.kernel.org/all/20240513082842.4117782-1-dev.jain@arm.com/ Andrew, does it sound reasonable to have the fixes tag in the above patch too, along with this series?
tools/testing/selftests/mm/compaction_test.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/tools/testing/selftests/mm/compaction_test.c b/tools/testing/selftests/mm/compaction_test.c index 533999b6c284..c5be395f8363 100644 --- a/tools/testing/selftests/mm/compaction_test.c +++ b/tools/testing/selftests/mm/compaction_test.c @@ -107,6 +107,8 @@ int check_compaction(unsigned long mem_free, unsigned int hugepage_size) goto close_fd; }
+ lseek(fd, 0, SEEK_SET); + /* Start with the initial condition of 0 huge pages*/ if (write(fd, "0", sizeof(char)) != sizeof(char)) { ksft_print_msg("Failed to write 0 to /proc/sys/vm/nr_hugepages: %s\n",
On Wed, 15 May 2024 15:06:32 +0530 Dev Jain dev.jain@arm.com wrote:
nr_hugepages is not set to zero because the file offset has not been reset after read(). Fix that using lseek().
Please fully describe the runtime effects of this bug.
On 5/20/24 05:30, Andrew Morton wrote:
On Wed, 15 May 2024 15:06:32 +0530 Dev Jain dev.jain@arm.com wrote:
nr_hugepages is not set to zero because the file offset has not been reset after read(). Fix that using lseek().
Please fully describe the runtime effects of this bug.
This is not a "bug", but a discrepancy; the following comment
by the author says "Start with the initial condition of 0 huge
pages", I am just ensuring that that is actually done. Although,
I am not sure about the utility of doing this in the first place,
since we are anyways trying to increase hugepages after that.
In the second patch, I have moved away this entire logic of
setting nr_hugepages to zero, to the place before we start
filling up memory; if you feel that this patch is unnecessary,
we may squash it.
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