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Adhemerval Zanella c579f48edb Remove cached PID/TID in clone
This patch remove the PID cache and usage in current GLIBC code.  Current
usage is mainly used a performance optimization to avoid the syscall,
however it adds some issues:

  - The exposed clone syscall will try to set pid/tid to make the new
    thread somewhat compatible with current GLIBC assumptions.  This cause
    a set of issue with new workloads and usecases (such as BZ#17214 and
    [1]) as well for new internal usage of clone to optimize other algorithms
    (such as clone plus CLONE_VM for posix_spawn, BZ#19957).

  - The caching complexity also added some bugs in the past [2] [3] and
    requires more effort of each port to handle such requirements (for
    both clone and vfork implementation).

  - Caching performance gain in mainly on getpid and some specific
    code paths.  The getpid performance leverage is questionable [4],
    either by the idea of getpid being a hotspot as for the getpid
    implementation itself (if it is indeed a justifiable hotspot a
    vDSO symbol could let to a much more simpler solution).

    Other usage is mainly for non usual code paths, such as pthread
    cancellation signal and handling.

For thread creation (on stack allocation) the code simplification in fact
adds some performance gain due the no need of transverse the stack cache
and invalidate each element pid.

Other thread usages will require a direct getpid syscall, such as
cancellation/setxid signal, thread cancellation, thread fail path (at
create_thread), and thread signal (pthread_kill and pthread_sigqueue).
However these are hardly usual hotspots and I think adding a syscall is
justifiable.

It also simplifies both the clone and vfork arch-specific implementation.
And by review each fork implementation there are some discrepancies that
this patch also solves:

  - microblaze clone/vfork does not set/reset the pid/tid field
  - hppa uses the default vfork implementation that fallback to fork.
    Since vfork is deprecated I do not think we should bother with it.

The patch also removes the TID caching in clone. My understanding for
such semantic is try provide some pthread usage after a user program
issue clone directly (as done by thread creation with CLONE_PARENT_SETTID
and pthread tid member).  However, as stated before in multiple discussions
threads, GLIBC provides clone syscalls without further supporting all this
semantics.

I ran a full make check on x86_64, x32, i686, armhf, aarch64, and powerpc64le.
For sparc32, sparc64, and mips I ran the basic fork and vfork tests from
posix/ folder (on a qemu system).  So it would require further testing
on alpha, hppa, ia64, m68k, nios2, s390, sh, and tile (I excluded microblaze
because it is already implementing the patch semantic regarding clone/vfork).

[1] https://codereview.chromium.org/800183004/
[2] https://sourceware.org/ml/libc-alpha/2006-07/msg00123.html
[3] https://sourceware.org/bugzilla/show_bug.cgi?id=15368
[4] http://yarchive.net/comp/linux/getpid_caching.html

	* sysdeps/nptl/fork.c (__libc_fork): Remove pid cache setting.
	* nptl/allocatestack.c (allocate_stack): Likewise.
	(__reclaim_stacks): Likewise.
	(setxid_signal_thread): Obtain pid through syscall.
	* nptl/nptl-init.c (sigcancel_handler): Likewise.
	(sighandle_setxid): Likewise.
	* nptl/pthread_cancel.c (pthread_cancel): Likewise.
	* sysdeps/unix/sysv/linux/pthread_kill.c (__pthread_kill): Likewise.
	* sysdeps/unix/sysv/linux/pthread_sigqueue.c (pthread_sigqueue):
	Likewise.
	* sysdeps/unix/sysv/linux/createthread.c (create_thread): Likewise.
	* sysdeps/unix/sysv/linux/getpid.c: Remove file.
	* nptl/descr.h (struct pthread): Change comment about pid value.
	* nptl/pthread_getattr_np.c (pthread_getattr_np): Remove thread
	pid assert.
	* sysdeps/unix/sysv/linux/pthread-pids.h (__pthread_initialize_pids):
	Do not set pid value.
	* nptl_db/td_ta_thr_iter.c (iterate_thread_list): Remove thread
	pid cache check.
	* nptl_db/td_thr_validate.c (td_thr_validate): Likewise.
	* sysdeps/aarch64/nptl/tcb-offsets.sym: Remove pid offset.
	* sysdeps/alpha/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/arm/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/hppa/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/i386/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/ia64/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/m68k/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/microblaze/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/mips/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/nios2/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/powerpc/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/s390/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/sh/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/sparc/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/tile/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/x86_64/nptl/tcb-offsets.sym: Likewise.
	* sysdeps/unix/sysv/linux/aarch64/clone.S: Remove pid and tid caching.
	* sysdeps/unix/sysv/linux/alpha/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/arm/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/hppa/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/i386/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/ia64/clone2.S: Likewise.
	* sysdeps/unix/sysv/linux/mips/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/nios2/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/sh/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/tile/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/aarch64/vfork.S: Remove pid set and reset.
	* sysdeps/unix/sysv/linux/alpha/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/arm/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/i386/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/ia64/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/m68k/clone.S: Likewise.
	* sysdeps/unix/sysv/linux/m68k/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/mips/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/nios2/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/sh/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/tile/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/vfork.S: Likewise.
	* sysdeps/unix/sysv/linux/tst-clone2.c (f): Remove direct pthread
	struct access.
	(clone_test): Remove function.
	(do_test): Rewrite to take in consideration pid is not cached anymore.
2016-11-24 19:38:51 -02:00
argp Installed-header hygiene (BZ#20366): Simple self-contained fixes. 2016-09-23 08:43:55 -04:00
assert
benchtests Use -fno-builtin for sqrt benchmark. 2016-10-21 21:18:03 +00:00
bits Refactor float_t, double_t information into bits/flt-eval-method.h. 2016-11-24 18:44:50 +00:00
catgets
conform Enable linknamespace testing for libdl and libcrypt. 2016-11-16 22:47:57 +00:00
crypt Fix crypt snprintf namespace (bug 20829). 2016-11-16 22:46:48 +00:00
csu Remove __libc_csu_irel declaration 2016-09-10 15:50:53 +05:30
ctype
debug
dirent
dlfcn Fix warning caused by unused-result in bug-atexit3-lib.cc 2016-10-28 19:26:14 -02:00
elf elf: Assume TLS is initialized in _dl_map_object_from_fd 2016-11-23 13:12:03 +01:00
gmon Installed-header hygiene (BZ#20366): obsolete BSD u_* types. 2016-09-23 08:43:56 -04:00
gnulib
grp
gshadow
hesiod
hurd Fix hurd __access_noerrno implementation. 2016-11-18 16:49:08 -02:00
iconv gconv.h: fix build with GCC 7 2016-11-06 21:33:10 +01:00
iconvdata Bug 20729: Fix building with -Os. 2016-10-29 23:50:56 -04:00
include Fix hurd __access_noerrno implementation. 2016-11-18 16:49:08 -02:00
inet Installed-header hygiene (BZ#20366): conditionally defined structures. 2016-09-23 08:43:56 -04:00
intl hurd: fix pathconf visibility 2016-09-18 23:45:12 +02:00
io New internal function __access_noerrno 2016-11-16 15:53:58 -02:00
libidn
libio Fix tst-memstream3 build failure 2016-10-02 10:24:32 -03:00
locale Bug 20729: Include libc-internal.h where required. 2016-10-31 16:46:57 -04:00
localedata localedata: lt_LT: use hyphens in d_fmt [BZ #20497] 2016-08-24 16:07:02 -04:00
login
mach Fix old-style function definition 2016-09-20 23:10:51 +02:00
malloc malloc: Update comments about chunk layout 2016-10-28 22:36:58 +02:00
manual Add setpayload, setpayloadf, setpayloadl. 2016-11-19 00:16:28 +00:00
math Refactor float_t, double_t information into bits/flt-eval-method.h. 2016-11-24 18:44:50 +00:00
mathvec
misc Fix multiple definitions of mk[o]stemp[s]64 2016-11-22 13:51:19 +01:00
nis Installed-header hygiene (BZ#20366): Simple self-contained fixes. 2016-09-23 08:43:55 -04:00
nptl Remove cached PID/TID in clone 2016-11-24 19:38:51 -02:00
nptl_db Remove cached PID/TID in clone 2016-11-24 19:38:51 -02:00
nscd
nss
po
posix Fix writes past the allocated array bounds in execvpe (BZ#20847) 2016-11-22 10:23:07 -02:00
pwd
resolv Bug 20729: Fix build failures on ppc64 and other arches. 2016-11-02 13:01:36 -04:00
resource
rt Use libc_ifunc macro for clock_* symbols in librt. 2016-10-07 10:12:47 +02:00
scripts build-many-glibcs: Revert -fno-isolate-erroneous-paths options for tilepro 2016-11-23 12:25:23 -05:00
setjmp
shadow
signal Installed-header hygiene (BZ#20366): time.h types. 2016-09-23 08:43:56 -04:00
socket Installed-header hygiene (BZ#20366): conditionally defined structures. 2016-09-23 08:43:56 -04:00
soft-fp [soft-fp] Add support for various half-precision conversion routines. 2016-09-21 21:02:54 +00:00
stdio-common Fix crypt snprintf namespace (bug 20829). 2016-11-16 22:46:48 +00:00
stdlib Ignore -Wmaybe-uninitialized in stdlib/bug-getcontext.c. 2016-11-11 21:05:51 +00:00
streams
string Correct comments in string.h re strcoll_l, strxfrm_l. 2016-11-16 14:18:32 -05:00
sunrpc Fix build-and-build-again bug in sunrpc tests. 2016-11-14 14:25:11 -05:00
sysdeps Remove cached PID/TID in clone 2016-11-24 19:38:51 -02:00
sysvipc Installed-header hygiene (BZ#20366): time.h types. 2016-09-23 08:43:56 -04:00
termios
time Fix -Wformat-length warning in time/tst-strptime2.c 2016-11-02 16:00:39 -07:00
timezone
wcsmbs
wctype
.gitattributes
.gitignore
abi-tags
aclocal.m4
BUGS
ChangeLog Remove cached PID/TID in clone 2016-11-24 19:38:51 -02:00
ChangeLog.1
ChangeLog.2
ChangeLog.3
ChangeLog.4
ChangeLog.5
ChangeLog.6
ChangeLog.7
ChangeLog.8
ChangeLog.9
ChangeLog.10
ChangeLog.11
ChangeLog.12
ChangeLog.13
ChangeLog.14
ChangeLog.15
ChangeLog.16
ChangeLog.17
ChangeLog.old-ports
ChangeLog.old-ports-aarch64
ChangeLog.old-ports-aix
ChangeLog.old-ports-alpha
ChangeLog.old-ports-am33
ChangeLog.old-ports-arm
ChangeLog.old-ports-cris
ChangeLog.old-ports-hppa
ChangeLog.old-ports-ia64
ChangeLog.old-ports-linux-generic
ChangeLog.old-ports-m68k
ChangeLog.old-ports-microblaze
ChangeLog.old-ports-mips
ChangeLog.old-ports-powerpc
ChangeLog.old-ports-tile
config.h.in Add configure check to test if gcc supports attribute ifunc. 2016-10-07 10:02:59 +02:00
config.make.in Avoid running $(CXX) during build to obtain header file paths 2016-09-21 10:45:32 +02:00
configure configure: accept __stack_chk_fail_local for ssp support too [BZ #20662] 2016-11-15 14:15:19 -05:00
configure.ac configure: accept __stack_chk_fail_local for ssp support too [BZ #20662] 2016-11-15 14:15:19 -05:00
CONFORMANCE
COPYING
COPYING.LIB
cppflags-iterator.mk
extra-lib.mk
extra-modules.mk
gen-locales.mk
INSTALL Add configure check to test if gcc supports attribute ifunc. 2016-10-07 10:02:59 +02:00
libc-abis
LICENSES
Makeconfig Generate .op pattern rules for profiling builds only 2016-09-21 10:45:19 +02:00
Makefile Installed header hygiene (BZ#20366): Test of installed headers. 2016-09-23 08:43:56 -04:00
Makefile.in
Makerules Avoid running $(CXX) during build to obtain header file paths 2016-09-21 10:45:32 +02:00
NAMESPACE
NEWS More NEWS entries / fixes for float_t / double_t changes. 2016-11-23 21:30:04 +00:00
o-iterator.mk
PROJECTS
README
Rules Do not generate UNRESOLVED results for run-built-tests = no. 2016-11-04 21:29:00 +00:00
shlib-versions
test-skeleton.c Document do_test in test-skeleton.c 2016-11-07 08:28:52 -08:00
version.h
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