diff options
Diffstat (limited to 'nptl')
| -rw-r--r-- | nptl/ChangeLog | 6 | ||||
| -rw-r--r-- | nptl/allocatestack.c | 45 |
2 files changed, 46 insertions, 5 deletions
diff --git a/nptl/ChangeLog b/nptl/ChangeLog index 559fcb3819..6e14988ad4 100644 --- a/nptl/ChangeLog +++ b/nptl/ChangeLog @@ -1,3 +1,9 @@ +2003-02-03 Ulrich Drepper <drepper@redhat.com> + + * allocatestack.c (allocate_stack): Implement coloring of the + allocated stack memory. Rename pagesize to pagesize_m1. It's the + size minus one. Adjust users. + 2003-02-02 Ulrich Drepper <drepper@redhat.com> * allocatestack.c: Improve comment throughout the file. diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c index 4e9826beb5..4ec3f44047 100644 --- a/nptl/allocatestack.c +++ b/nptl/allocatestack.c @@ -77,6 +77,9 @@ hidden_def (__stack_user) /* Number of threads running. */ static unsigned int nptl_nthreads = 1; +/* Number of threads created. */ +static unsigned int nptl_ncreated; + /* Check whether the stack is still used or not. */ #define FREE_P(descr) ((descr)->tid == 0) @@ -224,10 +227,10 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, { struct pthread *pd; size_t size; - size_t pagesize = __sysconf (_SC_PAGESIZE); + size_t pagesize_m1 = __sysconf (_SC_PAGESIZE) - 1; assert (attr != NULL); - assert (powerof2 (pagesize)); + assert (powerof2 (pagesize_m1 + 1)); assert (TCB_ALIGNMENT >= STACK_ALIGN); /* Get the stack size from the attribute if it is set. Otherwise we @@ -309,15 +312,24 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, size_t reqsize; void *mem; +#if COLORING_INCREMENT != 0 + /* Add one more page for stack coloring. Don't to 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 - 1); assert (size != 0); /* Make sure the size of the stack is enough for the guard and eventually the thread descriptor. */ - guardsize = (attr->guardsize + pagesize - 1) & ~(pagesize - 1); + guardsize = (attr->guardsize + pagesize_m1) & ~pagesize_m1; if (__builtin_expect (size < (guardsize + __static_tls_size - + MINIMAL_REST_STACK), 0)) + + MINIMAL_REST_STACK + pagesize_m1 + 1), + 0)) /* The stack is too small (or the guard too large). */ return EINVAL; @@ -336,8 +348,31 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, never get a NULL pointer back from MMAP. */ assert (mem != NULL); +#if COLORING_INCREMENT != 0 + /* Atomically increment NCREATED. */ + unsigned int ncreated = atomic_exchange_and_add (&nptl_ncreated, 1); + + /* 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 (__builtin_expect ((coloring & (__static_tls_align - 1)) != 0, 0)) + coloring = (((coloring + __static_tls_align - 1) + & ~(__static_tls_align - 1)) + & ~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. */ - pd = (struct pthread *) ((char *) mem + size) - 1; + pd = (struct pthread *) ((char *) mem + size - coloring) - 1; /* Remember the stack-related values. */ pd->stackblock = mem; |