diff --git a/src/port/pg_numa.c b/src/port/pg_numa.c index 4b487a2a4e8..d5935207d0a 100644 --- a/src/port/pg_numa.c +++ b/src/port/pg_numa.c @@ -29,6 +29,19 @@ #include #include +/* + * numa_move_pages() chunk size, has to be <= 16 to work around a kernel bug + * in do_pages_stat() (chunked by DO_PAGES_STAT_CHUNK_NR). By using the same + * chunk size, we make it work even on unfixed kernels. + * + * 64-bit system are not affected by the bug, and so use much larger chunks. + */ +#if SIZEOF_SIZE_T == 4 +#define NUMA_QUERY_CHUNK_SIZE 16 +#else +#define NUMA_QUERY_CHUNK_SIZE 1024 +#endif + /* libnuma requires initialization as per numa(3) on Linux */ int pg_numa_init(void) @@ -42,11 +55,46 @@ pg_numa_init(void) * We use move_pages(2) syscall here - instead of get_mempolicy(2) - as the * first one allows us to batch and query about many memory pages in one single * giant system call that is way faster. + * + * We call numa_move_pages() for smaller chunks of the whole array. The first + * reason is to work around a kernel bug, but also to allow interrupting the + * query between the calls (for many pointers processing the whole array can + * take a lot of time). */ int pg_numa_query_pages(int pid, unsigned long count, void **pages, int *status) { - return numa_move_pages(pid, count, pages, NULL, status, 0); + unsigned long next = 0; + int ret = 0; + + /* + * Chunk pointers passed to numa_move_pages to NUMA_QUERY_CHUNK_SIZE + * items, to work around a kernel bug in do_pages_stat(). + */ + while (next < count) + { + unsigned long count_chunk = Min(count - next, + NUMA_QUERY_CHUNK_SIZE); + + /* + * Bail out if any of the chunks errors out (ret<0). We ignore + * (ret>0) which is used to return number of nonmigrated pages, + * but we're not migrating any pages here. + */ + ret = numa_move_pages(pid, count_chunk, &pages[next], NULL, &status[next], 0); + if (ret < 0) + { + /* plain error, return as is */ + return ret; + } + + next += count_chunk; + } + + /* should have consumed the input array exactly */ + Assert(next == count); + + return 0; } int