From 2af00decb8b198abbcb8c3baf4adfab31e86e05e Mon Sep 17 00:00:00 2001 From: Konstantin Belousov Date: Tue, 8 Sep 2009 15:31:23 +0000 Subject: MFC r196730: Remove the altkstacks, instead instantiate threads with kernel stack allocated with the right size from the start. For the thread that has kernel stack cached, verify that requested stack size is equial to the actual, and reallocate the stack if sizes differ. Introduce separate kernel stack cache that keeps some limited amount of preallocated kernel stacks to lower the latency of thread allocation. Not a merge: instead of removing td_altkstack* members of struct thread, replace them with placeholders to keep struct thread layout on the stable branch. Also, record r196640, r196644 and r196648 as merged. Approved by: re (kensmith) --- sys/kern/kern_fork.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) (limited to 'sys/kern/kern_fork.c') diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c index 4e2eaa98f3aa..03d8cbc6bc1e 100644 --- a/sys/kern/kern_fork.c +++ b/sys/kern/kern_fork.c @@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$"); #include "opt_kdtrace.h" #include "opt_ktrace.h" +#include "opt_kstack_pages.h" #include #include @@ -276,25 +277,29 @@ norfproc_fail: mem_charged = 0; vm2 = NULL; + if (pages == 0) + pages = KSTACK_PAGES; /* Allocate new proc. */ newproc = uma_zalloc(proc_zone, M_WAITOK); - if (TAILQ_EMPTY(&newproc->p_threads)) { - td2 = thread_alloc(); + td2 = FIRST_THREAD_IN_PROC(newproc); + if (td2 == NULL) { + td2 = thread_alloc(pages); if (td2 == NULL) { error = ENOMEM; goto fail1; } proc_linkup(newproc, td2); - } else - td2 = FIRST_THREAD_IN_PROC(newproc); - - /* Allocate and switch to an alternate kstack if specified. */ - if (pages != 0) { - if (!vm_thread_new_altkstack(td2, pages)) { - error = ENOMEM; - goto fail1; + } else { + if (td2->td_kstack == 0 || td2->td_kstack_pages != pages) { + if (td2->td_kstack != 0) + vm_thread_dispose(td2); + if (!thread_alloc_stack(td2, pages)) { + error = ENOMEM; + goto fail1; + } } } + if ((flags & RFMEM) == 0) { vm2 = vmspace_fork(p1->p_vmspace, &mem_charged); if (vm2 == NULL) { -- cgit v1.2.3