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GNU C Library master sources branch master updated. glibc-2.25-8-g37f8aba
- From: azanella at sourceware dot org
- To: glibc-cvs at sourceware dot org
- Date: 6 Feb 2017 17:58:58 -0000
- Subject: GNU C Library master sources branch master updated. glibc-2.25-8-g37f8aba
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http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=37f8abad1c7b274e66eaf2d04684bd8a7ba0bcef
commit 37f8abad1c7b274e66eaf2d04684bd8a7ba0bcef
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Mon Jan 30 18:07:32 2017 -0200
nptl: Remove COLORING_INCREMENT
This patch removes the COLORING_INCREMENT define and usage on allocatestack.c.
It has not been used since 564cd8b67ec487f (glibc-2.3.3) by any architecture.
The idea is to simplify the code by removing obsolete code.
* nptl/allocatestack.c [COLORING_INCREMENT] (nptl_ncreated): Remove.
(allocate_stack): Remove COLORING_INCREMENT usage.
* nptl/stack-aliasing.h (COLORING_INCREMENT). Likewise.
* sysdeps/i386/i686/stack-aliasing.h (COLORING_INCREMENT): Likewise.
diff --git a/ChangeLog b/ChangeLog
index e4b1a86..710f9b4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2016-02-06 Adhemerval Zanella <adhemerval.zanella@linaro.org>
+
+ * nptl/allocatestack.c [COLORING_INCREMENT] (nptl_ncreated): Remove.
+ (allocate_stack): Remove COLORING_INCREMENT usage.
+ * nptl/stack-aliasing.h (COLORING_INCREMENT). Likewise.
+ * sysdeps/i386/i686/stack-aliasing.h (COLORING_INCREMENT): Likewise.
+
2017-02-06 Joseph Myers <joseph@codesourcery.com>
* manual/libm-err-tab.pl (@all_functions): Change to
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index 8a228ab..e5c5f79 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -125,11 +125,6 @@ static uintptr_t in_flight_stack;
list_t __stack_user __attribute__ ((nocommon));
hidden_data_def (__stack_user)
-#if COLORING_INCREMENT != 0
-/* Number of threads created. */
-static unsigned int nptl_ncreated;
-#endif
-
/* Check whether the stack is still used or not. */
#define FREE_P(descr) ((descr)->tid <= 0)
@@ -467,14 +462,6 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp,
const int prot = (PROT_READ | PROT_WRITE
| ((GL(dl_stack_flags) & PF_X) ? PROT_EXEC : 0));
-#if COLORING_INCREMENT != 0
- /* Add one more page for stack coloring. Don't do it for stacks
- with 16 times pagesize or larger. This might just cause
- unnecessary misalignment. */
- if (size <= 16 * pagesize_m1)
- size += pagesize_m1 + 1;
-#endif
-
/* Adjust the stack size for alignment. */
size &= ~__static_tls_align_m1;
assert (size != 0);
@@ -513,34 +500,11 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp,
So we can never get a null pointer back from mmap. */
assert (mem != NULL);
-#if COLORING_INCREMENT != 0
- /* Atomically increment NCREATED. */
- unsigned int ncreated = atomic_increment_val (&nptl_ncreated);
-
- /* We chose the offset for coloring by incrementing it for
- every new thread by a fixed amount. The offset used
- module the page size. Even if coloring would be better
- relative to higher alignment values it makes no sense to
- do it since the mmap() interface does not allow us to
- specify any alignment for the returned memory block. */
- size_t coloring = (ncreated * COLORING_INCREMENT) & pagesize_m1;
-
- /* Make sure the coloring offsets does not disturb the alignment
- of the TCB and static TLS block. */
- if (__glibc_unlikely ((coloring & __static_tls_align_m1) != 0))
- coloring = (((coloring + __static_tls_align_m1)
- & ~(__static_tls_align_m1))
- & ~pagesize_m1);
-#else
- /* Unless specified we do not make any adjustments. */
-# define coloring 0
-#endif
-
/* Place the thread descriptor at the end of the stack. */
#if TLS_TCB_AT_TP
- pd = (struct pthread *) ((char *) mem + size - coloring) - 1;
+ pd = (struct pthread *) ((char *) mem + size) - 1;
#elif TLS_DTV_AT_TP
- pd = (struct pthread *) ((((uintptr_t) mem + size - coloring
+ pd = (struct pthread *) ((((uintptr_t) mem + size
- __static_tls_size)
& ~__static_tls_align_m1)
- TLS_PRE_TCB_SIZE);
diff --git a/nptl/stack-aliasing.h b/nptl/stack-aliasing.h
index 4d6c013..73ee4de 100644
--- a/nptl/stack-aliasing.h
+++ b/nptl/stack-aliasing.h
@@ -16,12 +16,6 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-/* This is a number of bytes (less than a page) by which to "color" the
- starting stack address of new threads. This number is multiplied by the
- number of threads created so far and then truncated modulo page size,
- to get a roughly even distribution of values for different threads. */
-#define COLORING_INCREMENT 0
-
/* This is a number of bytes that is an alignment that should be avoided
when choosing the exact size of a new thread's stack. If the size
chosen is aligned to this, an extra page will be added to render the
diff --git a/sysdeps/i386/i686/stack-aliasing.h b/sysdeps/i386/i686/stack-aliasing.h
index 7872e47..9b5a1b0 100644
--- a/sysdeps/i386/i686/stack-aliasing.h
+++ b/sysdeps/i386/i686/stack-aliasing.h
@@ -16,11 +16,6 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-/* It turns out that stack coloring is in general not good on P4s. Some
- applications will benefit. We will probably have a configuration option
- at some point. To enable coloring, set this to 128. */
-#define COLORING_INCREMENT 0
-
/* What is useful is to avoid the 64k aliasing problem which reliably
happens if all stacks use sizes which are a multiple of 64k. Tell
the stack allocator to disturb this by allocation one more page if
-----------------------------------------------------------------------
Summary of changes:
ChangeLog | 7 ++++++
nptl/allocatestack.c | 40 +----------------------------------
nptl/stack-aliasing.h | 6 -----
sysdeps/i386/i686/stack-aliasing.h | 5 ----
4 files changed, 9 insertions(+), 49 deletions(-)
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