diff options
Diffstat (limited to 'src/os_win')
| -rw-r--r-- | src/os_win/os_fs.c | 23 | ||||
| -rw-r--r-- | src/os_win/os_mtx_cond.c | 43 | ||||
| -rw-r--r-- | src/os_win/os_snprintf.c | 50 | ||||
| -rw-r--r-- | src/os_win/os_thread.c | 20 | ||||
| -rw-r--r-- | src/os_win/os_vsnprintf.c | 41 | ||||
| -rw-r--r-- | src/os_win/os_yield.c | 8 |
6 files changed, 105 insertions, 80 deletions
diff --git a/src/os_win/os_fs.c b/src/os_win/os_fs.c index 2f76fff04a5..5cf47ea5763 100644 --- a/src/os_win/os_fs.c +++ b/src/os_win/os_fs.c @@ -87,22 +87,19 @@ __win_fs_rename(WT_FILE_SYSTEM *file_system, WT_ERR(__wt_to_utf16_string(session, to, &to_wide)); /* - * Check if file exists since Windows does not override the file if - * it exists. + * We want an atomic rename, but that's not guaranteed by MoveFileExW + * (or by any MSDN API). Don't set the MOVEFILE_COPY_ALLOWED flag to + * prevent the system from falling back to a copy and delete process. + * Do set the MOVEFILE_WRITE_THROUGH flag so the window is as small + * as possible, just in case. WiredTiger renames are done in a single + * directory and we expect that to be an atomic metadata update on any + * modern filesystem. */ - if (GetFileAttributesW(to_wide->data) != INVALID_FILE_ATTRIBUTES) - if (DeleteFileW(to_wide->data) == FALSE) { - windows_error = __wt_getlasterror(); - __wt_errx(session, - "%s: file-rename: DeleteFileW: %s", - to, __wt_formatmessage(session, windows_error)); - WT_ERR(__wt_map_windows_error(windows_error)); - } - - if (MoveFileW(from_wide->data, to_wide->data) == FALSE) { + if (MoveFileExW(from_wide->data, to_wide->data, + MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH) == FALSE) { windows_error = __wt_getlasterror(); __wt_errx(session, - "%s to %s: file-rename: MoveFileW: %s", + "%s to %s: file-rename: MoveFileExW: %s", from, to, __wt_formatmessage(session, windows_error)); WT_ERR(__wt_map_windows_error(windows_error)); } diff --git a/src/os_win/os_mtx_cond.c b/src/os_win/os_mtx_cond.c index 79c62ccd7f2..0001c6c2322 100644 --- a/src/os_win/os_mtx_cond.c +++ b/src/os_win/os_mtx_cond.c @@ -13,8 +13,7 @@ * Allocate and initialize a condition variable. */ int -__wt_cond_alloc(WT_SESSION_IMPL *session, - const char *name, bool is_signalled, WT_CONDVAR **condp) +__wt_cond_alloc(WT_SESSION_IMPL *session, const char *name, WT_CONDVAR **condp) { WT_CONDVAR *cond; @@ -26,7 +25,7 @@ __wt_cond_alloc(WT_SESSION_IMPL *session, InitializeConditionVariable(&cond->cond); cond->name = name; - cond->waiters = is_signalled ? -1 : 0; + cond->waiters = 0; *condp = cond; return (0); @@ -38,8 +37,8 @@ __wt_cond_alloc(WT_SESSION_IMPL *session, * out period expires, let the caller know. */ void -__wt_cond_wait_signal( - WT_SESSION_IMPL *session, WT_CONDVAR *cond, uint64_t usecs, bool *signalled) +__wt_cond_wait_signal(WT_SESSION_IMPL *session, WT_CONDVAR *cond, + uint64_t usecs, bool (*run_func)(WT_SESSION_IMPL *), bool *signalled) { BOOL sleepret; DWORD milliseconds, windows_error; @@ -59,8 +58,26 @@ __wt_cond_wait_signal( EnterCriticalSection(&cond->mtx); locked = true; + /* + * It's possible to race with threads waking us up. That's not a problem + * if there are multiple wakeups because the next wakeup will get us, or + * if we're only pausing for a short period. It's a problem if there's + * only a single wakeup, our waker is likely waiting for us to exit. + * After acquiring the mutex (so we're guaranteed to be awakened by any + * future wakeup call), optionally check if we're OK to keep running. + * This won't ensure our caller won't just loop and call us again, but + * at least it's not our fault. + * + * Assert we're not waiting longer than a second if not checking the + * run status. + */ + WT_ASSERT(session, run_func != NULL || usecs <= WT_MILLION); + + if (run_func != NULL && !run_func(session)) + goto skipping; + if (usecs > 0) { - milliseconds64 = usecs / 1000; + milliseconds64 = usecs / WT_THOUSAND; /* * Check for 32-bit unsigned integer overflow @@ -90,7 +107,7 @@ __wt_cond_wait_signal( if (sleepret == 0) { windows_error = __wt_getlasterror(); if (windows_error == ERROR_TIMEOUT) { - *signalled = false; +skipping: *signalled = false; sleepret = 1; } } @@ -117,17 +134,17 @@ void __wt_cond_signal(WT_SESSION_IMPL *session, WT_CONDVAR *cond) { WT_DECL_RET; - bool locked; - - locked = false; __wt_verbose(session, WT_VERB_MUTEX, "signal %s", cond->name); /* - * Our callers are often setting flags to cause a thread to exit. Add - * a barrier to ensure the flags are seen by the threads. + * Our callers often set flags to cause a thread to exit. Add a barrier + * to ensure exit flags are seen by the sleeping threads, otherwise we + * can wake up a thread, it immediately goes back to sleep, and we'll + * hang. Use a full barrier (we may not write before waiting on thread + * join). */ - WT_WRITE_BARRIER(); + WT_FULL_BARRIER(); /* * Fast path if we are in (or can enter), a state where the next waiter diff --git a/src/os_win/os_snprintf.c b/src/os_win/os_snprintf.c index a6056ff9342..f3025b12a60 100644 --- a/src/os_win/os_snprintf.c +++ b/src/os_win/os_snprintf.c @@ -8,17 +8,47 @@ #include "wt_internal.h" -_Check_return_opt_ int __cdecl _wt_snprintf( - _Out_writes_(_MaxCount) char * _DstBuf, - _In_ size_t _MaxCount, - _In_z_ _Printf_format_string_ const char * _Format, ...) +/* + * __wt_vsnprintf_len_incr -- + * POSIX vsnprintf convenience function, incrementing the returned size. + */ +int +__wt_vsnprintf_len_incr( + char *buf, size_t size, size_t *retsizep, const char *fmt, va_list ap) { - va_list args; - WT_DECL_RET; + int len; + + /* + * WiredTiger calls with length 0 to get the needed buffer size. Call + * the count only version in this case, _vsnprintf_s will invoke the + * invalid parameter handler if count is less than or equal to zero. + */ + if (size == 0) { + *retsizep += (size_t)_vscprintf(fmt, ap); + return (0); + } + + /* + * Additionally, the invalid parameter handler is invoked if buffer or + * format is a NULL pointer. + */ + if (buf == NULL || fmt == NULL) + return (EINVAL); + + /* + * If the storage required to store the data and a terminating null + * exceeds size, the invalid parameter handler is invoked, unless + * count is _TRUNCATE, in which case as much of the string as will + * fit in the buffer is written and -1 returned. + */ + if ((len = _vsnprintf_s(buf, size, _TRUNCATE, fmt, ap)) >= 0) { + *retsizep += (size_t)len; + return (0); + } - va_start(args, _Format); - ret = _wt_vsnprintf(_DstBuf, _MaxCount, _Format, args); - va_end(args); + /* Return the buffer size required. */ + if (len == -1) + *retsizep += (size_t)_vscprintf(fmt, ap); - return (ret); + return (0); } diff --git a/src/os_win/os_thread.c b/src/os_win/os_thread.c index a34dff776b6..4c8f212bb4f 100644 --- a/src/os_win/os_thread.c +++ b/src/os_win/os_thread.c @@ -16,6 +16,13 @@ int __wt_thread_create(WT_SESSION_IMPL *session, wt_thread_t *tidret, WT_THREAD_CALLBACK(*func)(void *), void *arg) { + /* + * Creating a thread isn't a memory barrier, but WiredTiger commonly + * sets flags and or state and then expects worker threads to start. + * Include a barrier to ensure safety in those cases. + */ + WT_FULL_BARRIER(); + /* Spawn a new thread of control. */ *tidret = (HANDLE)_beginthreadex(NULL, 0, func, arg, 0, NULL); if (*tidret != 0) @@ -33,6 +40,13 @@ __wt_thread_join(WT_SESSION_IMPL *session, wt_thread_t tid) { DWORD windows_error; + /* + * Joining a thread isn't a memory barrier, but WiredTiger commonly + * sets flags and or state and then expects worker threads to halt. + * Include a barrier to ensure safety in those cases. + */ + WT_FULL_BARRIER(); + if ((windows_error = WaitForSingleObject(tid, INFINITE)) != WAIT_OBJECT_0) { if (windows_error == WAIT_FAILED) @@ -58,10 +72,10 @@ __wt_thread_join(WT_SESSION_IMPL *session, wt_thread_t tid) * __wt_thread_id -- * Fill in a printable version of the process and thread IDs. */ -void +int __wt_thread_id(char *buf, size_t buflen) { - (void)snprintf(buf, buflen, + return (__wt_snprintf(buf, buflen, "%" PRIu64 ":%" PRIu64, - (uint64_t)GetCurrentProcessId(), (uint64_t)GetCurrentThreadId); + (uint64_t)GetCurrentProcessId(), (uint64_t)GetCurrentThreadId)); } diff --git a/src/os_win/os_vsnprintf.c b/src/os_win/os_vsnprintf.c deleted file mode 100644 index 63f96e79d5b..00000000000 --- a/src/os_win/os_vsnprintf.c +++ /dev/null @@ -1,41 +0,0 @@ -/*- - * Copyright (c) 2014-2016 MongoDB, Inc. - * Copyright (c) 2008-2014 WiredTiger, Inc. - * All rights reserved. - * - * See the file LICENSE for redistribution information. - */ - -#include "wt_internal.h" - -_Check_return_opt_ int __cdecl _wt_vsnprintf( - _Out_writes_(_MaxCount) char * _DstBuf, - _In_ size_t _MaxCount, - _In_z_ _Printf_format_string_ const char * _Format, - va_list _ArgList) -{ - int len; - - /* - * WiredTiger will call with length 0 to get the needed buffer size - * We call the count only version in this case since vsnprintf_s assumes - * length is greater than zero or else it triggers the invalid_parameter - * handler. - */ - if (_MaxCount == 0) { - return _vscprintf(_Format, _ArgList); - } - - len = (size_t)_vsnprintf_s( - _DstBuf, _MaxCount, _TRUNCATE, _Format, _ArgList); - - /* - * The MSVC implementation returns -1 on truncation instead of what - * it would have written. We could let callers iteratively grow the - * buffer, or just ask us how big a buffer they would like. - */ - if (len == -1) - len = _vscprintf(_Format, _ArgList) + 1; - - return (len); -} diff --git a/src/os_win/os_yield.c b/src/os_win/os_yield.c index aab1559e072..038f2efe162 100644 --- a/src/os_win/os_yield.c +++ b/src/os_win/os_yield.c @@ -15,5 +15,13 @@ void __wt_yield(void) { + /* + * Yielding the processor isn't documented as a memory barrier, and it's + * a reasonable expectation to have. There's no reason not to explicitly + * include a barrier since we're giving up the CPU, and ensures callers + * aren't ever surprised. + */ + WT_FULL_BARRIER(); + SwitchToThread(); } |