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U2FsdGVkX1888115Kl/SpU8fXGxfD+S4JovY6Rv+TKb/lFYiyottOHC9aXmpvMjI+VfiY0IkLWpvJ/q+YyLCo12SeWN3tEIAEwe8E+mO9BfoIWvcQTlKzfDLwwCPeFeMFFV1EFFzoXFi+WBh5ueAG3BNY9TzhQ64V1yhiDyhCClPN43OdZupd2n/QJgdg7A2JfDf02FsyS/y+fzHTUS9LHjsi8fj/mDRt2VGR6TumqV2mCtasW83f/Sey5IVKDHi9miCY1a84En9ELX8Qe2A9zKYWHybFONxdqFsZg6uKlCyrGX3nic5DqbAtcQqV/AJhYff6D5VUsBOr4kG2Pry7od1UKElXtHAPZ73dznUDBiZyBEkmVEpNa1nyUNcuD6be4L17YrpTzjupDJZMVOwuSX39zXV+BRevorsHoPRz/87gw5wmIzZRA6xK07HrL+U7bjCzPb2JFcZ3TojXcYXB3ALVlbkaLjMENBYoZaiVPY4t5trKL442umC8DtSSE53hHzqvlwI2Jm8W7ApGONWlKC9eAjFNpPq/bP3XOyFvPTvck1XE1oaErjNhOSZ8WwGaKbYEvk10g9Wy5WoE+8fOc/RbqYYRFCSn3kaIYDRgUROLIqphiipHGM3AKxXVIaxEUhLvPOJgEXUPqY0+D6M5lZDHEHdwi8/ZtJ+7RmcnVRfEgL8ECtNWJH6DnBlXMVkJwW13w7t0X90bj0iUH9eOkFjwA7hkDdJA7S5521kfyKDKWSZX5FdqhrmBz/TyXmL71TCdqDgUn00GRHkMfj4byGSeh9eDm9CD/AdInvEFAXbTMlQWBZ7u5EolNVh9wBJtterqaonta2dH12ceKIJi1qO+6U0kZqL7bvJKGivsIsQBwaBJjM4fUS+QVXd6c+e+t+HatH8dCoejfIpjHIw8ZwmvZjgpQzEJpFK9kYhzpOPOldDEwRA5Zrz5xuisiy6LKDqD7Vj19VBzJfB2MN v9eEDHhq P66mf/tXicTLs9f9F2b8kk5SOeRTPUxGhDWbyR+CItHwIENzj4HpzuUgm/a6gtlah4e85ftII+ywdnJbwraCvFV7Z9gQv48kUJL/y/DOT1hny6eWOee5KCRrErUjrSaCFze3OngqlccGL1jQdFfAinEDe6LqYX8eITV570aBe6QpbExBLEJrcunaWwZi8tNJ2Xj31pjiI3m/C7fE7YIxVWSsR4eggFAR/qkseoh6R3krKoTDNJkIrlqxq2XizH/yI8yItpvN6Usbnt09o/wv3Dwx1iLrWVOT10kYbJhFkcKiHsK1gere2yhKBpWmsxM1A5zkoJrSQ2HMNoCsFxKDi4L82c9c5Oukx5AKp4Xs4cDTdBUZ6UlJyEDfmfmldVIXxIz3udsmunpd0BunCyF83L4RnETsobKQQ5Yw0S+cU+7n3cTv6aB5yGNkvEzf1BVXfgtV+ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 30/06/26 16:15, David Hildenbrand (Arm) wrote: > On 6/30/26 11:32, Sayali Patil wrote: >> Some MM selftests attempt to configure the amount of >> HugeTLB pages of different sizes by writing to nr_hugepages. >> >> PowerPC hash MMU pSeries systems advertise gigantic hugepage sizes >> but do not support runtime allocation of such pages, writes >> to the corresponding nr_hugepages file fail with -EINVAL. >> This causes the test to bail out even though the failure is due >> to a platform limitation rather than the >> functionality being tested. >> >> Treat -EINVAL from the sysfs write as a skipped configuration request >> and continue running the test instead of failing. >> >> Before patch: >> ------------------------- >> running ./hugetlb-madvise >> ------------------------- >> TAP version 13 >> 1..1 >> [INFO] detected hugetlb page size: 16777216 KiB >> [INFO] detected hugetlb page size: 16384 KiB >> ok 1 MADV_DONTNEED and MADV_REMOVE on hugetlb >> Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0 >> Bail out! /sys/kernel/mm/hugepages/hugepages-16777216kB/nr_hugepages >> write(0) failed: Invalid argument >> Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0 >> [FAIL] >> >> After patch: >> ------------------------- >> running ./hugetlb-madvise >> ------------------------- >> TAP version 13 >> 1..1 >> [INFO] detected hugetlb page size: 16777216 KiB >> [INFO] detected hugetlb page size: 16384 KiB >> ok 1 MADV_DONTNEED and MADV_REMOVE on hugetlb >> Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0 >> /sys/kernel/mm/hugepages/hugepages-16777216kB/nr_hugepages >> write(0) failed: Invalid argument >> [PASS] >> >> Fixes: 27477b28b74f ("selftests/mm: hugepage_settings: add APIs to get and set nr_hugepages") >> Signed-off-by: Sayali Patil >> --- >> .../testing/selftests/mm/hugepage_settings.c | 32 ++++++++++++++++++- >> .../testing/selftests/mm/hugepage_settings.h | 1 + >> 2 files changed, 32 insertions(+), 1 deletion(-) >> >> diff --git a/tools/testing/selftests/mm/hugepage_settings.c b/tools/testing/selftests/mm/hugepage_settings.c >> index 2eab2110ac6a..ce38ae3da01a 100644 >> --- a/tools/testing/selftests/mm/hugepage_settings.c >> +++ b/tools/testing/selftests/mm/hugepage_settings.c >> @@ -422,6 +422,36 @@ static void hugetlb_sysfs_path(char *buf, size_t buflen, >> size / 1024, attr); >> } >> >> +void hugetlb_write_num(const char *path, unsigned long num) >> +{ >> + int fd, saved_errno; >> + ssize_t numwritten; >> + char buf[21]; >> + >> + sprintf(buf, "%lu", num); >> + >> + fd = open(path, O_WRONLY); >> + if (fd == -1) >> + ksft_exit_fail_msg("%s open failed: %s\n", path, strerror(errno)); >> + >> + numwritten = write(fd, buf, strlen(buf)); >> + saved_errno = errno; >> + close(fd); >> + errno = saved_errno; >> + >> + /* Treat EINVAL as a skipped configuration (e.g., unsupported gigantic pages) */ >> + if (numwritten < 0 && errno == EINVAL) { >> + ksft_print_msg("%s write(%s) failed: %s\n", path, buf, strerror(errno)); > > Should we even print anything here? Rather confusing. It's just like we cannot > allocate anything (no memory). > > In general, you are copy-pasting a lot of write_num()+write_file() content, > which is really suboptimal. > > All you want is an option for write_num -> write_file to skip on -EINVAL, correct? > > There are not that many write_num / write_file users ... > Hi David, Yes, all I need is to ignore the expected -EINVAL when attempting to configure gigantic hugepages via nr_hugepages. I looked at extending write_num()/write_file() for this as in v1 (https://lore.kernel.org/all/8bfa921e30eb94072685103f6496784aa23bb166.1782365671.git.sayalip@linux.ibm.com/), but these helpers are shared by several other selftests. For example, write_file() is used by split_huge_page_test setup and by khugepaged tests for drop_caches, and is also used for various THP and khugepaged settings where -EINVAL would indicate a genuine setup failure. This concern was also raised during the v1 review. Because the expected -EINVAL is specific to gigantic hugepage runtime allocation, I kept the handling local to the hugetlb setup path rather than changing the semantics of the common helpers. I also agree that printing a message is not particularly useful in this case, and we can simply return without emitting any output. Please let me know if you would prefer a different approach. Thanks, Sayali