and 'rusage' without having to copy data to/from stackgap buffers.
The old split (find_stopped_child) could be removed.
amd64 seems to run netbsd32, linux and linux32 emulations. sparc64 compiles.
I think it existed to cache the numbers in kernel memory of a zombie when
proc->p_stats was part of the 'u' area - so got freed earlier and wouldn't
(easily) be accessible from a separate process. However since both the
p_ru and p_stats fields are freed at the same time it is no longer needed.
Ride the recent 4.99.19 version change.
Seems to be quite stable. Some work still left to do.
Please note, that syscalls are not yet MP-safe, because
of the file and vnode subsystems.
Reviewed by: <tech-kern>, <ad>
- Better detect simple cycles of threads calling _lwp_wait and return
EDEADLK. Does not handle deeper cycles like t1 -> t2 -> t3 -> t1.
- If there are multiple threads in _lwp_wait, then make sure that
targeted waits take precedence over waits for any LWP to exit.
- When checking for deadlock, also count the number of zombies currently
in the process as potentially reapable. Whenever a zombie is murdered,
kick all waiters to make them check again for deadlock.
- Add more comments.
Also, while here:
- LOCK_ASSERT -> KASSERT in some places
- lwp_free: change boolean arguments to type 'bool'.
- proc_free: let lwp_free spin waiting for the last LWP to exit, there's
no reason to do it here.
P_*/L_* naming convention, and rename the in-kernel flags to avoid
conflict. (P_ -> PK_, L_ -> LW_ ). Add back the (now unused) LSDEAD
constant.
Restores source compatibility with pre-newlock2 tools like ps or top.
Reviewed by Andrew Doran.
process was reparented. Change proc_free() to copy the rusage to a buffer
on the stack if required, so it can be passed both to the debugger and
to the real parent process.
Fixes kern/35582 (kernel panics with gdb).
Instead, free an LWP's specificdata from lwp_exit() (if it is not the
last LWP) or exit1() (if it is the last LWP). For consistency, free the
proc's specificdata from exit1() as well. Add lwp_finispecific() and
proc_finispecific() functions to make this more convenient.
Members of the thread group must die without reporting to the parent and
without going to zombie stage. We do that by reparenting to init before
catching a SIGKILL. The parent will not see the child death.
The thread group leader must report the exit status, even if it exits
because of another thread calling exit_group(). We do that by storing the
exit status in struct linux_emuldata_shared, and the exit hook has the
duty of setting struct proc's p_xstat for the thread group leader.
2) For exit/fork/exec hooks, move the NPTL specific code to separate functions
that are shared between COMPAT_LINUX and COMPAT_LINUX32
3) Fix LINUX_CLONE_PARENT_SETTID semantics
a proclist and call the specified function for each of them.
primarily to fix a procfs locking problem, but i think that it's useful for
others as well.
while i'm here, introduce PROCLIST_FOREACH macro, which is similar to
LIST_FOREACH but skips marker entries which are used by proclist_foreach_call.
- move per VP data into struct sadata_vp referenced from l->l_savp
* VP id
* lock on VP data
* LWP on VP
* recently blocked LWP on VP
* queue of LWPs woken which ran on this VP before sleep
* faultaddr
* LWP cache for upcalls
* upcall queue
- add current concurrency and requested concurrency variables
- make process exit run LWP on all VPs
- make signal delivery consider all VPs
- make timer events consider all VPs
- add sa_newsavp to allocate new sadata_vp structure
- add sa_increaseconcurrency to prepare new VP
- make sys_sa_setconcurrency request new VP or wakeup idle VP
- make sa_yield lower current concurrency
- set sa_cpu = VP id in upcalls
- maintain cached LWPs per VP
re-used by another cpu immediately. in that case, lwp_exit2() will
access freed memory. to fix this:
- remove curlwp from p_lwps in exit1() rather than letting lwp_exit2() do so.
- add assertions to ensure freed proc has no lwps.
kern/24329 from me and kern/24574 from Havard Eidnes.
the latter is not a appropriate place to do so and it broke vfork.
- deactivate pmap before calling cpu_exit() to keep a balance of
pmap_activate/deactivate.
process context ('reaper').
From within the exiting process context:
* deactivate pmap and free vmspace while we can still block
* introduce MD cpu_lwp_free() - this cleans all MD-specific context (such
as FPU state), and is the last potentially blocking operation;
all of cpu_wait(), and most of cpu_exit(), is now folded into cpu_lwp_free()
* process is now immediatelly marked as zombie and made available for pickup
by parent; the remaining last lwp continues the exit as fully detached
* MI (rather than MD) code bumps uvmexp.swtch, cpu_exit() is now same
for both 'process' and 'lwp' exit
uvm_lwp_exit() is modified to never block; the u-area memory is now
always just linked to the list of available u-areas. Introduce (blocking)
uvm_uarea_drain(), which is called to release the excessive u-area memory;
this is called by parent within wait4(), or by pagedaemon on memory shortage.
uvm_uarea_free() is now private function within uvm_glue.c.
MD process/lwp exit code now always calls lwp_exit2() immediatelly after
switching away from the exiting lwp.
g/c now unneeded routines and variables, including the reaper kernel thread
an offset between ss_sp and struct sa_stackinfo_t (located in struct
__pthread_st) when calling sa_register. The kernel increments the
sast_gen counter in struct sastack when an upcall stack is used.
libpthread increments the sasi_stackgen counter in struct
sa_stackinfo_t when an upcall stack is freed. The kernel compares the
two counters to decide if a stack is free or in use.
- add struct sa_stackinfo_t with sasi_stackgen to count stack use in
userland
- add sast_gen to struct sastack to count stack use in kernel
- add SA_FLAG_STACKINFO to enable the stackinfo_offset argument in the
sa_register syscall
- add sa_stackinfo_offset to struct sadata for offset between ss_sp
and struct sa_stackinfo_t
- add ssize_t stackinfo_offset argument to sa_register, initialize
struct sadata's sa_stackinfo_offset from it if SA_FLAG_STACKINFO is
set
- add sa_getstack, sa_getstack0, sa_stackused and sa_setstackfree
functions to find/use/free upcall stacks and use these where
appropriate
- don't record stack for upcall in sa_upcall0
- pass sau to sa_switchcall instead of l2 (l2 = curlwp in sa_switchcall)
- add sa_vp_blocker to struct sadata to pass recently blocked lwp to
sa_switchcall
- delay finding a stack for blocked upcalls to sa_switchcall
- add sa_stacknext to struct sadata pointing to next most likely free
upcall stack; also g/c sa_stackslist in struct sadata and sast_list
in struct sastack
- add L_SA_WOKEN flag: LWP is on sa_woken queue
- add L_SA_RECYCLE flag: LWP should be recycled in sa_setwoken
- replace l_upcallstack with L_SA_WOKEN/L_SA_RECYCLE/L_SA_BLOCKING
flags
- g/c now unused sast_blocker in struct sastack
- make sa_switchcall, sa_upcall0 and sa_upcall_getstate static in
kern_sa.c
- call sa_upcall_userret only once in userret
- split sa_makeupcalls out of sa_upcall_userret and use to process
the sa_upcalls queue
- on process exit: mark LWPs sleeping in saunblock interruptible; also
there are no LWPs sleeping on l->l_upcallstack anymore; also clear
sa_wokenq_head to prevent unblocked upcalls
additional changes:
- cleanup timerupcall sa_vp == curlwp check
- add check in sa_yield if we didn't block on our way here and we
wouldn't any longer be the LWP on the VP
- invalidate sa_vp_ofaultaddr after resolving pagefault
- use splay tree for the pagefault check if the thread was running on
an upcall stack.
=> removes the limitation that all upcall stacks need to be
adjoining and that all upcall stacks have to be loaded with the
1st sys_sa_stacks call.
=> enables keeping information associated with a stack in the kernel
which makes it simpler to find out which LWP is using a stack.
=> allows increasing the SA_MAXNUMSTACKS without having to
allocate an array of that size.
of the sibling list so that find_stopped_child can be optimised to avoid
traversing the entire sibling list - helps when a process has a lot of
children.
- Modify locking in pfind() and pgfind() to that the caller can rely on the
result being valid, allow caller to request that zombies be findable.
- Rename pfind() to p_find() to ensure we break binary compatibility.
- Remove svr4_pfind since p_find willnow do the job.
- Modify some of the SMP locking of the proc lists - signals are still stuffed.
Welcome to 1.6ZF
dsl