Author: kib Date: Sat Aug 24 14:29:13 2019 New Revision: 351453 URL: https://svnweb.freebsd.org/changeset/base/351453
Log: Make stack grow use the same gap as stack create. Store stack_guard_page * PAGE_SIZE into the gap->next_read field at the time of the stack creation. This makes the used guard size consistent between stack creation and stack grow time. Suggested by: alc Reviewed by: alc, markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D21384 Modified: head/sys/vm/vm_map.c Modified: head/sys/vm/vm_map.c ============================================================================== --- head/sys/vm/vm_map.c Sat Aug 24 13:26:34 2019 (r351452) +++ head/sys/vm/vm_map.c Sat Aug 24 14:29:13 2019 (r351453) @@ -4189,8 +4189,20 @@ vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, rv = vm_map_insert(map, NULL, 0, gap_bot, gap_top, VM_PROT_NONE, VM_PROT_NONE, MAP_CREATE_GUARD | (orient == MAP_STACK_GROWS_DOWN ? MAP_CREATE_STACK_GAP_DN : MAP_CREATE_STACK_GAP_UP)); - if (rv != KERN_SUCCESS) + if (rv == KERN_SUCCESS) { + /* + * Gap can never successfully handle a fault, so + * read-ahead logic is never used for it. Re-use + * next_read of the gap entry to store + * stack_guard_page for vm_map_growstack(). + */ + if (orient == MAP_STACK_GROWS_DOWN) + new_entry->prev->next_read = sgp; + else + new_entry->next->next_read = sgp; + } else { (void)vm_map_delete(map, bot, top); + } return (rv); } @@ -4231,7 +4243,6 @@ vm_map_growstack(vm_map_t map, vm_offset_t addr, vm_ma MPASS(!map->system_map); - guard = stack_guard_page * PAGE_SIZE; lmemlim = lim_cur(curthread, RLIMIT_MEMLOCK); stacklim = lim_cur(curthread, RLIMIT_STACK); vmemlim = lim_cur(curthread, RLIMIT_VMEM); @@ -4258,6 +4269,7 @@ retry: } else { return (KERN_FAILURE); } + guard = gap_entry->next_read; max_grow = gap_entry->end - gap_entry->start; if (guard > max_grow) return (KERN_NO_SPACE); _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
