From cef5dfd75aca85d5fd3996d387cfee5a28b467c7 Mon Sep 17 00:00:00 2001 From: Christopher Faylor Date: Mon, 15 Mar 2010 21:29:15 +0000 Subject: * 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. --- winsup/cygwin/spinlock.h | 66 ++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 53 insertions(+), 13 deletions(-) (limited to 'winsup/cygwin/spinlock.h') 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*/ - -- cgit v1.2.3