diff options
author | Christopher Faylor <me@cgf.cx> | 2010-03-16 00:29:15 +0300 |
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committer | Christopher Faylor <me@cgf.cx> | 2010-03-16 00:29:15 +0300 |
commit | cef5dfd75aca85d5fd3996d387cfee5a28b467c7 (patch) | |
tree | 118617d399410aeb76a778c48c7de8dbaed5df66 /winsup/cygwin/spinlock.h | |
parent | 654e623ce009fc0d430eed044519539e624938cc (diff) |
* shared_info.h (user_info): Add dll_crt0_1 as a friend.
(user_info::version): Make LONG to accommodate spinlock use.
(user_info::create): New static function renamed from user_info_create.
(user_info::initialize): New private function renamed from
user_info_initialize.
(SHARED_VERSION): Delete.
(SHARED_VERSION_MAGIC): Ditto.
(USER_VERSION_MAGIC): Ditto.
(SHARED_INFO_CB): Ditto.
(USER_VERSION): Ditto.
(USER_VERSION_MAGIC): Ditto.
(CURR_SHARED_MAGIC): Update.
(CURR_USER_MAGIC): Ditto.
(shared_info::version): Make LONG to accommodate spinlock use.
(shared_info::create): New static function mirroring user_info::create.
(dll_crt0_1): Accommodate change to user_info::initialize.
* spinlock.h (spinlock::setto): New variable member.
(spinlock::done): New function.
(spinlock::spinlock): Generalize to allow arbitrary values and timeouts. Call
done() when lock is not needed.
* ntdll.h: Make multiple-inclusion safe.
(NtQuerySystemTime): Declare.
* shared.cc (installation_root_inited): Rename from shared_mem_inited.
(init_installation_root): Make inline. Use a spinlock to ensure that this is
initialized only once per session.
(user_info::initialize): Rename from user_shared_initialize. Protect with
spinlock on sversion and remove other spinlock-like things. Remove reference
to user_shared since it is now implicit. Refer to spinlock version of
multiple_cygwin_problem to ensure that any spinlock is released.
(user_info::create): Rename from user_shared_create. Accommodate change from
user_shared_initialize to user_info::initialize.
(shared_info::create): New inline function.
(shared_info::initialize): Protect with spinlock on sversion. Move heap_init
back under specific control of shared_info spinlock. Remove reference to
SHARED_INFO_CB and just use sizeof(*this).
(memory_init): Move all locking into respective functions where it is needed.
Accommodate name changes. Remove call to heap_init().
* syscalls.cc (seteuid32): Accommodate name change to user_info::create().
* mount.cc (mount_info::create_root_entry): Report on errors from add_item
since they should be nonexistent.
(mount_info::init): Don't initialize nmounts. It should already be zero. Give
more verbose error when root_idx < 0. Implicitly use this pointer rather than
explicitly referencing mount_table->.
(mount_info::add_item): Minor whitespace fix.
Diffstat (limited to 'winsup/cygwin/spinlock.h')
-rw-r--r-- | winsup/cygwin/spinlock.h | 66 |
1 files changed, 53 insertions, 13 deletions
diff --git a/winsup/cygwin/spinlock.h b/winsup/cygwin/spinlock.h index abf723acc..b55817245 100644 --- a/winsup/cygwin/spinlock.h +++ b/winsup/cygwin/spinlock.h @@ -11,30 +11,70 @@ details. */ #ifndef _SPINLOCK_H #define _SPINLOCK_H -#include "hires.h" +#include "ntdll.h" + +#define SPINLOCK_WAIT (15000LL * 10000LL) class spinlock { LONG *locker; LONG val; + LONG setto; + void done (LONG what) + { + if (locker) + { + InterlockedExchange (locker, what); + locker = NULL; + } + } + long long time () + { + LARGE_INTEGER t; + if (NtQuerySystemTime (&t) == STATUS_SUCCESS) + return get_ll (t); + return 0LL; + } public: - spinlock (LONG& locktest, LONGLONG timeout): - locker (&locktest) + spinlock (LONG& locktest, LONG wanted_val = 1, LONGLONG timeout = SPINLOCK_WAIT): + locker (&locktest), setto (wanted_val) { - if ((val = locktest) == 1) - return; - LONGLONG then = gtod.msecs (); - for (;;) + /* Quick test to see if we're already initialized */ + if ((val = locktest) == wanted_val) + locker = NULL; + /* Slightly less quick test to see if we are the first cygwin process */ + else if ((val = InterlockedExchange (locker, -1)) == 0) + /* We're armed and dangerous */; + else if (val == wanted_val) + done (val); /* This was initialized while we weren't looking */ + else { - if ((val = InterlockedExchange (locker, -1)) != -1 - || (gtod.msecs () - then) >= timeout) - break; - yield (); + long long then = time (); + /* Loop waiting for some other process to set locktest to something + other than -1, indicating that initialization has finished. Or, + wait a default of 15 seconds for that to happen and, if it doesn't + just grab the lock ourselves. */ + while ((val = InterlockedExchange (locker, -1)) == -1 + && (time () - then) < timeout) + yield (); + /* Reset the lock back to wanted_value under the assumption that is + what caused the above loop to kick out. */ + if (val == -1) + val = 0; /* Timed out. We'll initialize things ourselves. */ + else + done (val); /* Put back whatever was there before, assuming that + it is actually wanted_val. */ } } - ~spinlock () {InterlockedExchange (locker, 1);} + ~spinlock () {done (setto);} operator LONG () const {return val;} + /* FIXME: This should be handled in a more general fashion, probably by + establishing a linked list of spinlocks which are freed on process exit. */ + void multiple_cygwin_problem (const char *w, unsigned m, unsigned v) + { + done (val); + ::multiple_cygwin_problem (w, m, v); + } }; #endif /*_SPINLOCK_H*/ - |