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Diffstat (limited to '')
| -rw-r--r-- | include/import/plock.h | 439 |
1 files changed, 439 insertions, 0 deletions
diff --git a/include/import/plock.h b/include/import/plock.h new file mode 100644 index 0000000..058cc18 --- /dev/null +++ b/include/import/plock.h @@ -0,0 +1,439 @@ +/* plock - progressive locks + * + * Copyright (C) 2012-2017 Willy Tarreau <w@1wt.eu> + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES + * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT + * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, + * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + */ + +#include "atomic-ops.h" + +/* 64 bit */ +#define PLOCK64_RL_1 0x0000000000000004ULL +#define PLOCK64_RL_ANY 0x00000000FFFFFFFCULL +#define PLOCK64_SL_1 0x0000000100000000ULL +#define PLOCK64_SL_ANY 0x0000000300000000ULL +#define PLOCK64_WL_1 0x0000000400000000ULL +#define PLOCK64_WL_ANY 0xFFFFFFFC00000000ULL + +/* 32 bit */ +#define PLOCK32_RL_1 0x00000004 +#define PLOCK32_RL_ANY 0x0000FFFC +#define PLOCK32_SL_1 0x00010000 +#define PLOCK32_SL_ANY 0x00030000 +#define PLOCK32_WL_1 0x00040000 +#define PLOCK32_WL_ANY 0xFFFC0000 + +/* dereferences <*p> as unsigned long without causing aliasing issues */ +#define pl_deref_long(p) ({ volatile unsigned long *__pl_l = (void *)(p); *__pl_l; }) + +/* dereferences <*p> as unsigned int without causing aliasing issues */ +#define pl_deref_int(p) ({ volatile unsigned int *__pl_i = (void *)(p); *__pl_i; }) + +/* request shared read access (R), return non-zero on success, otherwise 0 */ +#define pl_try_r(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + unsigned long __pl_r = pl_deref_long(lock) & PLOCK64_WL_ANY; \ + pl_barrier(); \ + if (!__builtin_expect(__pl_r, 0)) { \ + __pl_r = pl_xadd((lock), PLOCK64_RL_1) & PLOCK64_WL_ANY; \ + if (__builtin_expect(__pl_r, 0)) \ + pl_sub((lock), PLOCK64_RL_1); \ + } \ + !__pl_r; /* return value */ \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + unsigned int __pl_r = pl_deref_int(lock) & PLOCK32_WL_ANY; \ + pl_barrier(); \ + if (!__builtin_expect(__pl_r, 0)) { \ + __pl_r = pl_xadd((lock), PLOCK32_RL_1) & PLOCK32_WL_ANY; \ + if (__builtin_expect(__pl_r, 0)) \ + pl_sub((lock), PLOCK32_RL_1); \ + } \ + !__pl_r; /* return value */ \ + }) : ({ \ + void __unsupported_argument_size_for_pl_try_r__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_try_r__(__FILE__,__LINE__); \ + 0; \ + }) \ +) + +/* request shared read access (R) and wait for it */ +#define pl_take_r(lock) \ + do { \ + while (__builtin_expect(pl_try_r(lock), 1) == 0) \ + pl_cpu_relax(); \ + } while (0) + +/* release the read access (R) lock */ +#define pl_drop_r(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + pl_sub(lock, PLOCK64_RL_1); \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + pl_sub(lock, PLOCK32_RL_1); \ + }) : ({ \ + void __unsupported_argument_size_for_pl_drop_r__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_drop_r__(__FILE__,__LINE__); \ + }) \ +) + +/* request a seek access (S), return non-zero on success, otherwise 0 */ +#define pl_try_s(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + unsigned long __pl_r = pl_deref_long(lock); \ + pl_barrier(); \ + if (!__builtin_expect(__pl_r & (PLOCK64_WL_ANY | PLOCK64_SL_ANY), 0)) { \ + __pl_r = pl_xadd((lock), PLOCK64_SL_1 | PLOCK64_RL_1) & \ + (PLOCK64_WL_ANY | PLOCK64_SL_ANY); \ + if (__builtin_expect(__pl_r, 0)) \ + pl_sub((lock), PLOCK64_SL_1 | PLOCK64_RL_1); \ + } \ + !__pl_r; /* return value */ \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + unsigned int __pl_r = pl_deref_int(lock); \ + pl_barrier(); \ + if (!__builtin_expect(__pl_r & (PLOCK32_WL_ANY | PLOCK32_SL_ANY), 0)) { \ + __pl_r = pl_xadd((lock), PLOCK32_SL_1 | PLOCK32_RL_1) & \ + (PLOCK32_WL_ANY | PLOCK32_SL_ANY); \ + if (__builtin_expect(__pl_r, 0)) \ + pl_sub((lock), PLOCK32_SL_1 | PLOCK32_RL_1); \ + } \ + !__pl_r; /* return value */ \ + }) : ({ \ + void __unsupported_argument_size_for_pl_try_s__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_try_s__(__FILE__,__LINE__); \ + 0; \ + }) \ +) + +/* request a seek access (S) and wait for it */ +#define pl_take_s(lock) \ + do { \ + while (__builtin_expect(pl_try_s(lock), 0) == 0) \ + pl_cpu_relax(); \ + } while (0) + +/* release the seek access (S) lock */ +#define pl_drop_s(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + pl_sub(lock, PLOCK64_SL_1 + PLOCK64_RL_1); \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + pl_sub(lock, PLOCK32_SL_1 + PLOCK32_RL_1); \ + }) : ({ \ + void __unsupported_argument_size_for_pl_drop_s__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_drop_s__(__FILE__,__LINE__); \ + }) \ +) + +/* drop the S lock and go back to the R lock */ +#define pl_stor(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + pl_sub(lock, PLOCK64_SL_1); \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + pl_sub(lock, PLOCK32_SL_1); \ + }) : ({ \ + void __unsupported_argument_size_for_pl_stor__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_stor__(__FILE__,__LINE__); \ + }) \ +) + +/* take the W lock under the S lock */ +#define pl_stow(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + unsigned long __pl_r = pl_xadd((lock), PLOCK64_WL_1); \ + pl_barrier(); \ + while ((__pl_r & PLOCK64_RL_ANY) != PLOCK64_RL_1) \ + __pl_r = pl_deref_long(lock); \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + unsigned int __pl_r = pl_xadd((lock), PLOCK32_WL_1); \ + pl_barrier(); \ + while ((__pl_r & PLOCK32_RL_ANY) != PLOCK32_RL_1) \ + __pl_r = pl_deref_int(lock); \ + }) : ({ \ + void __unsupported_argument_size_for_pl_stow__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_stow__(__FILE__,__LINE__); \ + }) \ +) + +/* drop the W lock and go back to the S lock */ +#define pl_wtos(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + pl_sub(lock, PLOCK64_WL_1); \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + pl_sub(lock, PLOCK32_WL_1); \ + }) : ({ \ + void __unsupported_argument_size_for_pl_wtos__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_wtos__(__FILE__,__LINE__); \ + }) \ +) + +/* drop the W lock and go back to the R lock */ +#define pl_wtor(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + pl_sub(lock, PLOCK64_WL_1 | PLOCK64_SL_1); \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + pl_sub(lock, PLOCK32_WL_1 | PLOCK32_SL_1); \ + }) : ({ \ + void __unsupported_argument_size_for_pl_wtor__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_wtor__(__FILE__,__LINE__); \ + }) \ +) + +/* request a write access (W), return non-zero on success, otherwise 0. + * + * Below there is something important : by taking both W and S, we will cause + * an overflow of W at 4/5 of the maximum value that can be stored into W due + * to the fact that S is 2 bits, so we're effectively adding 5 to the word + * composed by W:S. But for all words multiple of 4 bits, the maximum value is + * multiple of 15 thus of 5. So the largest value we can store with all bits + * set to one will be met by adding 5, and then adding 5 again will place value + * 1 in W and value 0 in S, so we never leave W with 0. Also, even upon such an + * overflow, there's no risk to confuse it with an atomic lock because R is not + * null since it will not have overflown. For 32-bit locks, this situation + * happens when exactly 13108 threads try to grab the lock at once, W=1, S=0 + * and R=13108. For 64-bit locks, it happens at 858993460 concurrent writers + * where W=1, S=0 and R=858993460. + */ +#define pl_try_w(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + unsigned long __pl_r = pl_deref_long(lock); \ + pl_barrier(); \ + if (!__builtin_expect(__pl_r & (PLOCK64_WL_ANY | PLOCK64_SL_ANY), 0)) { \ + __pl_r = pl_xadd((lock), PLOCK64_WL_1 | PLOCK64_SL_1 | PLOCK64_RL_1); \ + if (__builtin_expect(__pl_r & (PLOCK64_WL_ANY | PLOCK64_SL_ANY), 0)) { \ + /* a writer, seeker or atomic is present, let's leave */ \ + pl_sub((lock), PLOCK64_WL_1 | PLOCK64_SL_1 | PLOCK64_RL_1); \ + __pl_r &= (PLOCK64_WL_ANY | PLOCK64_SL_ANY); /* return value */\ + } else { \ + /* wait for all other readers to leave */ \ + while (__pl_r) \ + __pl_r = pl_deref_long(lock) - \ + (PLOCK64_WL_1 | PLOCK64_SL_1 | PLOCK64_RL_1); \ + } \ + } \ + !__pl_r; /* return value */ \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + unsigned int __pl_r = pl_deref_int(lock); \ + pl_barrier(); \ + if (!__builtin_expect(__pl_r & (PLOCK32_WL_ANY | PLOCK32_SL_ANY), 0)) { \ + __pl_r = pl_xadd((lock), PLOCK32_WL_1 | PLOCK32_SL_1 | PLOCK32_RL_1); \ + if (__builtin_expect(__pl_r & (PLOCK32_WL_ANY | PLOCK32_SL_ANY), 0)) { \ + /* a writer, seeker or atomic is present, let's leave */ \ + pl_sub((lock), PLOCK32_WL_1 | PLOCK32_SL_1 | PLOCK32_RL_1); \ + __pl_r &= (PLOCK32_WL_ANY | PLOCK32_SL_ANY); /* return value */\ + } else { \ + /* wait for all other readers to leave */ \ + while (__pl_r) \ + __pl_r = pl_deref_int(lock) - \ + (PLOCK32_WL_1 | PLOCK32_SL_1 | PLOCK32_RL_1); \ + } \ + } \ + !__pl_r; /* return value */ \ + }) : ({ \ + void __unsupported_argument_size_for_pl_try_w__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_try_w__(__FILE__,__LINE__); \ + 0; \ + }) \ +) + +/* request a seek access (W) and wait for it */ +#define pl_take_w(lock) \ + do { \ + while (__builtin_expect(pl_try_w(lock), 0) == 0) \ + pl_cpu_relax(); \ + } while (0) + +/* drop the write (W) lock entirely */ +#define pl_drop_w(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + pl_sub(lock, PLOCK64_WL_1 | PLOCK64_SL_1 | PLOCK64_RL_1); \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + pl_sub(lock, PLOCK32_WL_1 | PLOCK32_SL_1 | PLOCK32_RL_1); \ + }) : ({ \ + void __unsupported_argument_size_for_pl_drop_w__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_drop_w__(__FILE__,__LINE__); \ + }) \ +) + +/* Try to upgrade from R to S, return non-zero on success, otherwise 0. + * This lock will fail if S or W are already held. In case of failure to grab + * the lock, it MUST NOT be retried without first dropping R, or it may never + * complete due to S waiting for R to leave before upgrading to W. + */ +#define pl_try_rtos(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + unsigned long __pl_r = pl_deref_long(lock); \ + pl_barrier(); \ + if (!__builtin_expect(__pl_r & (PLOCK64_WL_ANY | PLOCK64_SL_ANY), 0)) { \ + __pl_r = pl_xadd((lock), PLOCK64_SL_1) & \ + (PLOCK64_WL_ANY | PLOCK64_SL_ANY); \ + if (__builtin_expect(__pl_r, 0)) \ + pl_sub((lock), PLOCK64_SL_1); \ + } \ + !__pl_r; /* return value */ \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + unsigned int __pl_r = pl_deref_int(lock); \ + pl_barrier(); \ + if (!__builtin_expect(__pl_r & (PLOCK32_WL_ANY | PLOCK32_SL_ANY), 0)) { \ + __pl_r = pl_xadd((lock), PLOCK32_SL_1) & \ + (PLOCK32_WL_ANY | PLOCK32_SL_ANY); \ + if (__builtin_expect(__pl_r, 0)) \ + pl_sub((lock), PLOCK32_SL_1); \ + } \ + !__pl_r; /* return value */ \ + }) : ({ \ + void __unsupported_argument_size_for_pl_try_rtos__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_try_rtos__(__FILE__,__LINE__); \ + 0; \ + }) \ +) + + +/* request atomic write access (A), return non-zero on success, otherwise 0. + * It's a bit tricky as we only use the W bits for this and want to distinguish + * between other atomic users and regular lock users. We have to give up if an + * S lock appears. It's possible that such a lock stays hidden in the W bits + * after an overflow, but in this case R is still held, ensuring we stay in the + * loop until we discover the conflict. The lock only return successfully if all + * readers are gone (or converted to A). + */ +#define pl_try_a(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + unsigned long __pl_r = pl_deref_long(lock) & PLOCK64_SL_ANY; \ + pl_barrier(); \ + if (!__builtin_expect(__pl_r, 0)) { \ + __pl_r = pl_xadd((lock), PLOCK64_WL_1); \ + while (1) { \ + if (__builtin_expect(__pl_r & PLOCK64_SL_ANY, 0)) { \ + pl_sub((lock), PLOCK64_WL_1); \ + break; /* return !__pl_r */ \ + } \ + __pl_r &= PLOCK64_RL_ANY; \ + if (!__builtin_expect(__pl_r, 0)) \ + break; /* return !__pl_r */ \ + __pl_r = pl_deref_long(lock); \ + } \ + } \ + !__pl_r; /* return value */ \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + unsigned int __pl_r = pl_deref_int(lock) & PLOCK32_SL_ANY; \ + pl_barrier(); \ + if (!__builtin_expect(__pl_r, 0)) { \ + __pl_r = pl_xadd((lock), PLOCK32_WL_1); \ + while (1) { \ + if (__builtin_expect(__pl_r & PLOCK32_SL_ANY, 0)) { \ + pl_sub((lock), PLOCK32_WL_1); \ + break; /* return !__pl_r */ \ + } \ + __pl_r &= PLOCK32_RL_ANY; \ + if (!__builtin_expect(__pl_r, 0)) \ + break; /* return !__pl_r */ \ + __pl_r = pl_deref_int(lock); \ + } \ + } \ + !__pl_r; /* return value */ \ + }) : ({ \ + void __unsupported_argument_size_for_pl_try_a__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_try_a__(__FILE__,__LINE__); \ + 0; \ + }) \ +) + +/* request atomic write access (A) and wait for it */ +#define pl_take_a(lock) \ + do { \ + while (__builtin_expect(pl_try_a(lock), 1) == 0) \ + pl_cpu_relax(); \ + } while (0) + +/* release atomic write access (A) lock */ +#define pl_drop_a(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + pl_sub(lock, PLOCK64_WL_1); \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + pl_sub(lock, PLOCK32_WL_1); \ + }) : ({ \ + void __unsupported_argument_size_for_pl_drop_a__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_drop_a__(__FILE__,__LINE__); \ + }) \ +) + +/* Try to upgrade from R to A, return non-zero on success, otherwise 0. + * This lock will fail if S is held or appears while waiting (typically due to + * a previous grab that was disguised as a W due to an overflow). In case of + * failure to grab the lock, it MUST NOT be retried without first dropping R, + * or it may never complete due to S waiting for R to leave before upgrading + * to W. The lock succeeds once there's no more R (ie all of them have either + * completed or were turned to A). + */ +#define pl_try_rtoa(lock) ( \ + (sizeof(long) == 8 && sizeof(*(lock)) == 8) ? ({ \ + unsigned long __pl_r = pl_deref_long(lock) & PLOCK64_SL_ANY; \ + pl_barrier(); \ + if (!__builtin_expect(__pl_r, 0)) { \ + __pl_r = pl_xadd((lock), PLOCK64_WL_1 - PLOCK64_RL_1); \ + while (1) { \ + if (__builtin_expect(__pl_r & PLOCK64_SL_ANY, 0)) { \ + pl_sub((lock), PLOCK64_WL_1 - PLOCK64_RL_1); \ + break; /* return !__pl_r */ \ + } \ + __pl_r &= PLOCK64_RL_ANY; \ + if (!__builtin_expect(__pl_r, 0)) \ + break; /* return !__pl_r */ \ + __pl_r = pl_deref_long(lock); \ + } \ + } \ + !__pl_r; /* return value */ \ + }) : (sizeof(*(lock)) == 4) ? ({ \ + unsigned int __pl_r = pl_deref_int(lock) & PLOCK32_SL_ANY; \ + pl_barrier(); \ + if (!__builtin_expect(__pl_r, 0)) { \ + __pl_r = pl_xadd((lock), PLOCK32_WL_1 - PLOCK32_RL_1); \ + while (1) { \ + if (__builtin_expect(__pl_r & PLOCK32_SL_ANY, 0)) { \ + pl_sub((lock), PLOCK32_WL_1 - PLOCK32_RL_1); \ + break; /* return !__pl_r */ \ + } \ + __pl_r &= PLOCK32_RL_ANY; \ + if (!__builtin_expect(__pl_r, 0)) \ + break; /* return !__pl_r */ \ + __pl_r = pl_deref_int(lock); \ + } \ + } \ + !__pl_r; /* return value */ \ + }) : ({ \ + void __unsupported_argument_size_for_pl_try_rtoa__(char *,int); \ + if (sizeof(*(lock)) != 4 && (sizeof(long) != 8 || sizeof(*(lock)) != 8)) \ + __unsupported_argument_size_for_pl_try_rtoa__(__FILE__,__LINE__); \ + 0; \ + }) \ +) |