Bug #71355 [Com]: Fail to use huge page on power8 because of wrong page size

Edit report at https://bugs.php.net/bug.php?id=71355&edit=1 ID: 71355 Comment by: basu at us dot ibm dot com Reported by: jocelyn dot fournier at softizy dot com Summary: Fail to use huge page on power8 because of wrong page size Status: Open Type: Bug Package: opcache Operating System: Linux on Power PHP Version: 7.0.2 Block user comment: N Private report: N New Comment: Since linux on POWER supports huge page of size 16MB, it appears that this hard coded value of 2MB in ZendAccelerator.c is letting the mmap()/madvise()/munmap() fail with EINVAL due to invalid argument. This routine below with 2MB constant is only valid for promoting opcode cache to huge page.. This routine is not controlling the huge page semantics for PHP data allocations. However, there is a CHUNKSIZE buckets that are being managed by PHP 7.0.2 that does not have a size for huge page (max size for chunk size is only 2MB) I changed that to 16MB and was able to eliminate the mmap/madvise/munmap errors. Basically the chunk size management code should include huge page support on POWER. Previous Comments: ------------------------------------------------------------------------ [2016-01-12 23:06:34] jocelyn dot fournier at softizy dot com Description: ------------ Hi, It seems huge page size is hardcoded in the php src code : In ZendAccelerator.c for example, you have : static void accel_move_code_to_huge_pages(void) { FILE *f; long unsigned int huge_page_size = 2 * 1024 * 1024; However on IBM Power8 on linux, the default page size is 64KB ( http://www.redbooks.ibm.com/redbooks/pdfs/sg248171.pdf ). Hence when huge pages are enabled, php displays the following warning : munmap() failed: [22] Invalid argument strace output : [...] mmap(NULL, 2097152, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|0x40000, -1, 0) = 0x3effff000000 madvise(0x3effff000000, 2097152, MADV_HUGEPAGE) = -1 EINVAL (Invalid argument) [...] open("/usr/local/lib/php/extensions/no-debug-non-zts-20151012/apcu.so", O_RDONLY|O_CLOEXEC) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0\25\0\1\0\0\0\0`\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=121864, ...}) = 0 mmap(NULL, 158952, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3fff8e140000 mmap(0x3fff8e160000, 65536, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x10000) = 0x3fff8e160000 close(3) = 0 [...] munmap(0x3efff7000000, 134217728) = 0 close(3) = 0 munmap(0x3fff962c0000, 185272) = 0 munmap(0x3fff96240000, 82352) = 0 munmap(0x3fff96260000, 328760) = 0 munmap(0x3fff94210000, 33554432) = 0 munmap(0x3fff962f0000, 158952) = 0 brk(0x1001a8d0000) = 0x1001a8d0000 munmap(0x3fff96320000, 301576) = 0 munmap(0x3fff96210000, 196608) = 0 munmap(0x3effff000000, 2097152) = -1 EINVAL (Invalid argument) write(2, "\nmunmap() failed: [22] Invalid a"..., 40 munmap() failed: [22] Invalid argument ) = 40 munmap(0x3fff96370000, 327680) = 0 exit_group(0) = ? +++ exited with 0 +++ To fix the issue, the default page size should not be hardcoded, but should depend on the platform. Thanks and regards, Jocelyn Fournier Expected result: ---------------- No warning Actual result: -------------- munmap() failed: [22] Invalid argument ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=71355&edit=1