ISAR/libmdbx
3
0
Fork 0
mirror of https://github.com/isar/libmdbx.git synced 2025-01-02 01:14:13 +08:00
Code Issues Packages Projects Releases Wiki Activity

mdbx: add yielding for lck-testing for Windows if NDEBUG undefined.

Browse Source
This commit is contained in:
Leo Yuriev 2017-04-26 14:17:52 +03:00
parent 9a2806c6a8
commit 99002d016f
1 changed files with 34 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

69
src/lck-windows.c
View File

@ -24,6 +24,19 @@
* LY
*/
static __inline void jitter4testing(void) {
#ifndef NDEBUG
for (;;) {
unsigned coin = ((unsigned)__rdtsc() * 277u) % 43u;
if (coin < 43 / 3)
break;
SwitchToThread();
if (coin > 43 * 2 / 3)
Sleep(1);
}
#endif
}
/*----------------------------------------------------------------------------*/
/* rthc */
@ -98,44 +111,18 @@ void mdbx_rthc_unlock(void) { LeaveCriticalSection(&rthc_critical_section); }
#define LCK_WAITFOR 0
#define LCK_DONTWAIT LOCKFILE_FAIL_IMMEDIATELY
static BOOL flock(mdbx_filehandle_t fd, DWORD flags, off_t offset,
size_t bytes) {
static __inline BOOL flock(mdbx_filehandle_t fd, DWORD flags, off_t offset,
size_t bytes) {
OVERLAPPED ov;
ov.hEvent = 0;
ov.Offset = (DWORD)offset;
ov.OffsetHigh = HIGH_DWORD(offset);
#ifdef MDBX_WINDOWS_UnlockFile_CRUTCH
if (LockFileEx(fd, flags, 0, (DWORD)bytes, HIGH_DWORD(bytes), &ov))
return true;
if ((flags & LOCKFILE_FAIL_IMMEDIATELY) == 0)
return false;
int rc = GetLastError();
if (rc != ERROR_SHARING_VIOLATION && rc != ERROR_LOCK_VIOLATION)
return false;
/* FIXME: Windows kernel is ugly and mad... */
SwitchToThread();
Sleep(42);
SwitchToThread();
#endif /* MDBX_WINDOWS_UnlockFile_CRUTCH */
return LockFileEx(fd, flags, 0, (DWORD)bytes, HIGH_DWORD(bytes), &ov);
}
static BOOL funlock(mdbx_filehandle_t fd, off_t offset, size_t bytes) {
if (!UnlockFile(fd, (DWORD)offset, HIGH_DWORD(offset), (DWORD)bytes,
HIGH_DWORD(bytes)))
return false;
#ifdef MDBX_WINDOWS_UnlockFile_CRUTCH
/* FIXME: Windows kernel is ugly and mad... */
SwitchToThread();
Sleep(42);
SwitchToThread();
#endif /* MDBX_WINDOWS_UnlockFile_CRUTCH */
return true;
static __inline BOOL funlock(mdbx_filehandle_t fd, off_t offset, size_t bytes) {
return UnlockFile(fd, (DWORD)offset, HIGH_DWORD(offset), (DWORD)bytes,
HIGH_DWORD(bytes));
}
/*----------------------------------------------------------------------------*/
@ -219,18 +206,22 @@ static int internal_seize_lck(HANDLE lfd) {
assert(lfd != INVALID_HANDLE_VALUE);
/* 1) now on ?-? (free), get ?-E (middle) */
jitter4testing();
if (!flock(lfd, LCK_EXCLUSIVE | LCK_WAITFOR, LCK_UPPER)) {
rc = GetLastError() /* 2) something went wrong, give up */;
mdbx_error("%s(%s) failed: errcode %u", mdbx_func_,
"?-?(free) >> ?-E(middle)", rc);
return rc;
}
/* 3) now on ?-E (middle), try E-E (exclusive) */
jitter4testing();
if (flock(lfd, LCK_EXCLUSIVE | LCK_DONTWAIT, LCK_LOWER))
return MDBX_RESULT_TRUE; /* 4) got E-E (exclusive), done */
/* 5) still on ?-E (middle) */
rc = GetLastError();
jitter4testing();
if (rc != ERROR_SHARING_VIOLATION && rc != ERROR_LOCK_VIOLATION) {
/* 6) something went wrong, give up */
if (!funlock(lfd, LCK_UPPER)) {
@ -242,9 +233,11 @@ static int internal_seize_lck(HANDLE lfd) {
}
/* 7) still on ?-E (middle), try S-E (locked) */
jitter4testing();
rc = flock(lfd, LCK_SHARED | LCK_DONTWAIT, LCK_LOWER) ? MDBX_RESULT_FALSE
: GetLastError();
jitter4testing();
if (rc != MDBX_RESULT_FALSE)
mdbx_error("%s(%s) failed: errcode %u", mdbx_func_,
"?-E(middle) >> S-E(locked)", rc);
@ -267,6 +260,7 @@ int mdbx_lck_seize(MDB_env *env) {
assert(env->me_fd != INVALID_HANDLE_VALUE);
if (env->me_lfd == INVALID_HANDLE_VALUE) {
/* LY: without-lck mode (e.g. on read-only filesystem) */
jitter4testing();
if (!flock(env->me_fd, LCK_SHARED | LCK_DONTWAIT, LCK_WHOLE)) {
rc = GetLastError();
mdbx_error("%s(%s) failed: errcode %u", mdbx_func_, "without-lck", rc);
@ -276,6 +270,7 @@ int mdbx_lck_seize(MDB_env *env) {
}
rc = internal_seize_lck(env->me_lfd);
jitter4testing();
if (rc == MDBX_RESULT_TRUE && (env->me_flags & MDB_RDONLY) == 0) {
/* Check that another process don't operates in without-lck mode.
* Doing such check by exclusive locking the body-part of db. Should be
@ -287,11 +282,15 @@ int mdbx_lck_seize(MDB_env *env) {
rc = GetLastError();
mdbx_error("%s(%s) failed: errcode %u", mdbx_func_,
"lock-against-without-lck", rc);
jitter4testing();
mdbx_lck_destroy(env);
} else if (!funlock(env->me_fd, LCK_BODY)) {
rc = GetLastError();
mdbx_panic("%s(%s) failed: errcode %u", mdbx_func_,
"unlock-against-without-lck", rc);
} else {
jitter4testing();
if (!funlock(env->me_fd, LCK_BODY)) {
rc = GetLastError();
mdbx_panic("%s(%s) failed: errcode %u", mdbx_func_,
"unlock-against-without-lck", rc);
}
}
}