From ac42f990b85ae4034f16acf9929ce28e18ec2088 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Tue, 7 Jan 2025 14:42:12 -0500 Subject: [PATCH v2.3 11/30] aio: Core AIO implementation At this point nothing can use AIO - this commit does not include any implementation of aio subjects / callbacks. That will come in later commits. Todo: - lots of cleanup --- src/include/storage/aio.h | 301 ++++++ src/include/storage/aio_internal.h | 295 ++++++ src/include/storage/aio_types.h | 115 +++ src/include/utils/resowner.h | 5 + src/backend/access/transam/xact.c | 9 + src/backend/storage/aio/Makefile | 4 + src/backend/storage/aio/aio.c | 904 ++++++++++++++++++ src/backend/storage/aio/aio_callback.c | 280 ++++++ src/backend/storage/aio/aio_init.c | 186 ++++ src/backend/storage/aio/aio_io.c | 175 ++++ src/backend/storage/aio/aio_target.c | 108 +++ src/backend/storage/aio/meson.build | 4 + src/backend/storage/aio/method_sync.c | 47 + .../utils/activity/wait_event_names.txt | 3 + src/backend/utils/resowner/resowner.c | 30 + src/tools/pgindent/typedefs.list | 21 + 16 files changed, 2487 insertions(+) create mode 100644 src/include/storage/aio_internal.h create mode 100644 src/include/storage/aio_types.h create mode 100644 src/backend/storage/aio/aio_callback.c create mode 100644 src/backend/storage/aio/aio_io.c create mode 100644 src/backend/storage/aio/aio_target.c create mode 100644 src/backend/storage/aio/method_sync.c diff --git a/src/include/storage/aio.h b/src/include/storage/aio.h index 0e3fadac543..ffd382593d0 100644 --- a/src/include/storage/aio.h +++ b/src/include/storage/aio.h @@ -14,6 +14,9 @@ #ifndef AIO_H #define AIO_H +#include "storage/aio_types.h" +#include "storage/procnumber.h" + /* Enum for io_method GUC. */ @@ -26,9 +29,307 @@ typedef enum IoMethod #define DEFAULT_IO_METHOD IOMETHOD_SYNC +/* + * Flags for an IO that can be set with pgaio_io_set_flag(). + */ +typedef enum PgAioHandleFlags +{ + /* + * The IO references backend local memory. + * + * This needs to be set on an IO whenever the IO references process-local + * memory. Some IO methods do not support executing IO that references + * process local memory and thus need to fall back to executing IO + * synchronously for IOs with this flag set. + * + * Required for correctness. + */ + PGAIO_HF_REFERENCES_LOCAL = 1 << 1, + + /* + * Hint that IO will be executed synchronously. + * + * This can make it a bit cheaper to execute synchronous IO via the AIO + * interface, to avoid needing an AIO and non-AIO version of code. + * + * Advantageous to set, if applicable, but not required for correctness. + */ + PGAIO_HF_SYNCHRONOUS = 1 << 0, + + /* + * IO is using buffered IO, used to control heuristic in some IO methods. + * + * Advantageous to set, if applicable, but not required for correctness. + */ + PGAIO_HF_BUFFERED = 1 << 2, +} PgAioHandleFlags; + +/* + * The IO operations supported by the AIO subsystem. + * + * This could be in aio_internal.h, as it is not publically referenced, but + * PgAioOpData currently *does* need to be public, therefore keeping this + * public seems to make sense. + */ +typedef enum PgAioOp +{ + /* intentionally the zero value, to help catch zeroed memory etc */ + PGAIO_OP_INVALID = 0, + + PGAIO_OP_READV, + PGAIO_OP_WRITEV, + + /** + * In the near term we'll need at least: + * - fsync / fdatasync + * - flush_range + * + * Eventually we'll additionally want at least: + * - send + * - recv + * - accept + **/ +} PgAioOp; + +#define PGAIO_OP_COUNT (PGAIO_OP_WRITEV + 1) + + +/* + * On what is IO being performed. + * + * PgAioTargetID specific behaviour should be implemented in + * aio_target.c. + */ +typedef enum PgAioTargetID +{ + /* intentionally the zero value, to help catch zeroed memory etc */ + PGAIO_TID_INVALID = 0, +} PgAioTargetID; + +#define PGAIO_TID_COUNT (PGAIO_TID_INVALID + 1) + + +/* + * Data necessary for support IO operations (see PgAioOp). + * + * NB: Note that the FDs in here may *not* be relied upon for re-issuing + * requests (e.g. for partial reads/writes) - the FD might be from another + * process, or closed since. That's not a problem for IOs waiting to be issued + * only because the queue is flushed when closing an FD. + */ +typedef union +{ + struct + { + int fd; + uint16 iov_length; + uint64 offset; + } read; + + struct + { + int fd; + uint16 iov_length; + uint64 offset; + } write; +} PgAioOpData; + + +/* + * Information the object that IO is executed on. Mostly callbacks that + * operate on PgAioTargetData. + */ +typedef struct PgAioTargetInfo +{ + void (*reopen) (PgAioHandle *ioh); + + char *(*describe_identity) (const PgAioTargetData *sd); + + const char *name; +} PgAioTargetInfo; + + +/* + * IDs for callbacks that can be registered on an IO. + * + * Callbacks are identified by an ID rather than a function pointer. There are + * two main reasons: + * + * 1) Memory within PgAioHandle is precious, due to the number of PgAioHandle + * structs in pre-allocated shared memory. + * + * 2) Due to EXEC_BACKEND function pointers are not necessarily stable between + * different backends, therefore function pointers cannot directly be in + * shared memory. + * + * Without 2), we could fairly easily allow to add new callbacks, by filling a + * ID->pointer mapping table on demand. In the presence of 2 that's still + * doable, but harder, because every process has to re-register the pointers + * so that a local ID->"backend local pointer" mapping can be maintained. + */ +typedef enum PgAioHandleCallbackID +{ + PGAIO_HCB_INVALID, +} PgAioHandleCallbackID; + + +typedef void (*PgAioHandleCallbackStage) (PgAioHandle *ioh); +typedef PgAioResult (*PgAioHandleCallbackComplete) (PgAioHandle *ioh, PgAioResult prior_result); +typedef void (*PgAioHandleCallbackReport) (PgAioResult result, const PgAioTargetData *target_data, int elevel); + +typedef struct PgAioHandleCallbacks +{ + /* + * Prepare resources affected by the IO for execution. This could e.g. + * include moving ownership of buffer pins to the AIO subsystem. + */ + PgAioHandleCallbackStage stage; + + /* + * Update the state of resources affected by the IO to reflect completion + * of the IO. This could e.g. include updating shared buffer state to + * signal the IO has finished. + * + * The _shared suffix indicates that this is executed by the backend that + * completed the IO, which may or may not be the backend that issued the + * IO. Obviously the callback thus can only modify resources in shared + * memory. + * + * The latest registered callback is called first. This allows + * higher-level code to register callbacks that can rely on callbacks + * registered by lower-level code to already have been executed. + * + * NB: This is called in a critical section. Errors can be signalled by + * the callback's return value, it's the responsibility of the IO's issuer + * to react appropriately. + */ + PgAioHandleCallbackComplete complete_shared; + + /* + * Like complete_shared, except called in the issuing backend. + * + * This variant of the completion callback is useful when backend-local + * state has to be updated to reflect the IO's completion. E.g. a + * temporary buffer's BufferDesc isn't accessible in complete_shared. + * + * Local callbacks are only called after complete_shared for all + * registered callbacks has been called. + */ + PgAioHandleCallbackComplete complete_local; + + /* + * Report the result of an IO operation. This is e.g. used to raise an + * error after an IO failed at the appropriate time (i.e. not when the IO + * failed, but under control of the code that issued the IO). + */ + PgAioHandleCallbackReport report; +} PgAioHandleCallbacks; + + + +/* + * How many callbacks can be registered for one IO handle. Currently we only + * need two, but it's not hard to imagine needing a few more. + */ +#define PGAIO_HANDLE_MAX_CALLBACKS 4 + + + +/* AIO API */ + + +/* -------------------------------------------------------------------------------- + * IO Handles + * -------------------------------------------------------------------------------- + */ + +/* functions in aio.c */ +struct ResourceOwnerData; +extern PgAioHandle *pgaio_io_acquire(struct ResourceOwnerData *resowner, PgAioReturn *ret); +extern PgAioHandle *pgaio_io_acquire_nb(struct ResourceOwnerData *resowner, PgAioReturn *ret); + +extern void pgaio_io_release(PgAioHandle *ioh); +struct dlist_node; +extern void pgaio_io_release_resowner(struct dlist_node *ioh_node, bool on_error); + +extern void pgaio_io_set_flag(PgAioHandle *ioh, PgAioHandleFlags flag); + +extern int pgaio_io_get_id(PgAioHandle *ioh); +extern ProcNumber pgaio_io_get_owner(PgAioHandle *ioh); + +extern void pgaio_io_get_wref(PgAioHandle *ioh, PgAioWaitRef *iow); + +/* functions in aio_io.c */ +struct iovec; +extern int pgaio_io_get_iovec(PgAioHandle *ioh, struct iovec **iov); + +extern PgAioOpData *pgaio_io_get_op_data(PgAioHandle *ioh); + +extern void pgaio_io_prep_readv(PgAioHandle *ioh, + int fd, int iovcnt, uint64 offset); +extern void pgaio_io_prep_writev(PgAioHandle *ioh, + int fd, int iovcnt, uint64 offset); + +/* functions in aio_target.c */ +extern void pgaio_io_set_target(PgAioHandle *ioh, PgAioTargetID targetid); +extern bool pgaio_io_has_target(PgAioHandle *ioh); +extern PgAioTargetData *pgaio_io_get_target_data(PgAioHandle *ioh); +extern char *pgaio_io_get_target_description(PgAioHandle *ioh); + +/* functions in aio_callback.c */ +extern void pgaio_io_register_callbacks(PgAioHandle *ioh, PgAioHandleCallbackID cbid); +extern void pgaio_io_set_handle_data_64(PgAioHandle *ioh, uint64 *data, uint8 len); +extern void pgaio_io_set_handle_data_32(PgAioHandle *ioh, uint32 *data, uint8 len); +extern uint64 *pgaio_io_get_handle_data(PgAioHandle *ioh, uint8 *len); + + + +/* -------------------------------------------------------------------------------- + * IO Wait References + * -------------------------------------------------------------------------------- + */ + +extern void pgaio_wref_clear(PgAioWaitRef *iow); +extern bool pgaio_wref_valid(PgAioWaitRef *iow); +extern int pgaio_wref_get_id(PgAioWaitRef *iow); + +extern void pgaio_wref_wait(PgAioWaitRef *iow); +extern bool pgaio_wref_check_done(PgAioWaitRef *iow); + + + +/* -------------------------------------------------------------------------------- + * IO Result + * -------------------------------------------------------------------------------- + */ + +extern void pgaio_result_report(PgAioResult result, const PgAioTargetData *target_data, + int elevel); + + + +/* -------------------------------------------------------------------------------- + * Actions on multiple IOs. + * -------------------------------------------------------------------------------- + */ + +extern void pgaio_submit_staged(void); +extern bool pgaio_have_staged(void); + + + +/* -------------------------------------------------------------------------------- + * Other + * -------------------------------------------------------------------------------- + */ + +extern void pgaio_closing_fd(int fd); +extern void pgaio_at_xact_end(bool is_subxact, bool is_commit); +extern void pgaio_at_error(void); extern void assign_io_method(int newval, void *extra); + /* GUCs */ extern PGDLLIMPORT int io_method; extern PGDLLIMPORT int io_max_concurrency; diff --git a/src/include/storage/aio_internal.h b/src/include/storage/aio_internal.h new file mode 100644 index 00000000000..174d365f9c0 --- /dev/null +++ b/src/include/storage/aio_internal.h @@ -0,0 +1,295 @@ +/*------------------------------------------------------------------------- + * + * aio_internal.h + * AIO related declarations that shoul only be used by the AIO subsystem + * internally. + * + * + * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/storage/aio_internal.h + * + *------------------------------------------------------------------------- + */ +#ifndef AIO_INTERNAL_H +#define AIO_INTERNAL_H + + +#include "lib/ilist.h" +#include "port/pg_iovec.h" +#include "storage/aio.h" +#include "storage/condition_variable.h" + + +/* AFIXME */ +#define PGAIO_SUBMIT_BATCH_SIZE 32 + + + +typedef enum PgAioHandleState +{ + /* not in use */ + PGAIO_HS_IDLE = 0, + + /* returned by pgaio_io_acquire() */ + PGAIO_HS_HANDED_OUT, + + /* pgaio_io_prep_*() has been called, but IO hasn't been submitted yet */ + PGAIO_HS_DEFINED, + + /* target's stage() callback has been called, ready to be submitted */ + PGAIO_HS_STAGED, + + /* IO has been submitted and is being executed */ + PGAIO_HS_SUBMITTED, + + /* IO finished, but result has not yet been processed */ + PGAIO_HS_COMPLETED_IO, + + /* IO completed, shared completion has been called */ + PGAIO_HS_COMPLETED_SHARED, + + /* IO completed, local completion has been called */ + PGAIO_HS_COMPLETED_LOCAL, +} PgAioHandleState; + + +struct ResourceOwnerData; + +/* typedef is in public header */ +struct PgAioHandle +{ + /* all state updates should go through pgaio_io_update_state() */ + PgAioHandleState state:8; + + /* what are we operating on */ + PgAioTargetID target:8; + + /* which IO operation */ + PgAioOp op:8; + + /* bitfield of PgAioHandleFlags */ + uint8 flags; + + uint8 num_shared_callbacks; + + /* using the proper type here would use more space */ + uint8 shared_callbacks[PGAIO_HANDLE_MAX_CALLBACKS]; + + /* + * Length of data associated with handle using + * pgaio_io_set_handle_data_*(). + */ + uint8 handle_data_len; + + /* XXX: could be optimized out with some pointer math */ + int32 owner_procno; + + /* raw result of the IO operation */ + int32 result; + + /* + * Index into PgAioCtl->iovecs and PgAioCtl->handle_data. + * + * At the moment there's no need to differentiate between the two, but + * that won't necessarily stay that way. + */ + uint32 iovec_off; + + /** + * In which list the handle is registered, depends on the state: + * - IDLE, in per-backend list + * - HANDED_OUT - not in a list + * - DEFINED - in per-backend staged list + * - STAGED - in per-backend staged list + * - SUBMITTED - in issuer's in_flight list + * - COMPLETED_IO - in issuer's in_flight list + * - COMPLETED_SHARED - in issuer's in_flight list + **/ + dlist_node node; + + struct ResourceOwnerData *resowner; + dlist_node resowner_node; + + /* incremented every time the IO handle is reused */ + uint64 generation; + + ConditionVariable cv; + + /* result of shared callback, passed to issuer callback */ + PgAioResult distilled_result; + + PgAioReturn *report_return; + + PgAioOpData op_data; + + /* + * Data necessary to identify the object undergoing IO to higher-level + * code. Needs to be sufficient to allow another backend to reopen the + * file. + */ + PgAioTargetData target_data; +}; + + +typedef struct PgAioBackend +{ + /* index into PgAioCtl->io_handles */ + uint32 io_handle_off; + + /* IO Handles that currently are not used */ + dclist_head idle_ios; + + /* + * Only one IO may be returned by pgaio_io_acquire()/pgaio_io_acquire() + * without having been either defined (by actually associating it with IO) + * or by released (with pgaio_io_release()). This restriction is necessary + * to guarantee that we always can acquire an IO. ->handed_out_io is used + * to enforce that rule. + */ + PgAioHandle *handed_out_io; + + /* + * IOs that are defined, but not yet submitted. + */ + uint16 num_staged_ios; + PgAioHandle *staged_ios[PGAIO_SUBMIT_BATCH_SIZE]; + + /* + * List of in-flight IOs. Also contains IOs that aren't strict speaking + * in-flight anymore, but have been waited-for and completed by another + * backend. Once this backend sees such an IO it'll be reclaimed. + * + * The list is ordered by submission time, with more recently submitted + * IOs being appended at the end. + */ + dclist_head in_flight_ios; +} PgAioBackend; + + +typedef struct PgAioCtl +{ + int backend_state_count; + PgAioBackend *backend_state; + + /* + * Array of iovec structs. Each iovec is owned by a specific backend. The + * allocation is in PgAioCtl to allow the maximum number of iovecs for + * individual IOs to be configurable with PGC_POSTMASTER GUC. + */ + uint64 iovec_count; + struct iovec *iovecs; + + /* + * For, e.g., an IO covering multiple buffers in shared / temp buffers, we + * need to get Buffer IDs during completion to be able to change the + * BufferDesc state accordingly. This space can be used to store e.g. + * Buffer IDs. Note that the actual iovec might be shorter than this, + * because we combine neighboring pages into one larger iovec entry. + */ + uint64 *handle_data; + + uint64 io_handle_count; + PgAioHandle *io_handles; +} PgAioCtl; + + + +/* + * The set of callbacks that each IO method must implement. + * + * AFIXME: Document these. + */ +typedef struct IoMethodOps +{ + /* global initialization */ + size_t (*shmem_size) (void); + void (*shmem_init) (bool first_time); + + /* per-backend initialization */ + void (*init_backend) (void); + + /* handling of IOs */ + bool (*needs_synchronous_execution) (PgAioHandle *ioh); + int (*submit) (uint16 num_staged_ios, PgAioHandle **staged_ios); + + void (*wait_one) (PgAioHandle *ioh, + uint64 ref_generation); +} IoMethodOps; + + +/* aio.c */ +extern bool pgaio_io_was_recycled(PgAioHandle *ioh, uint64 ref_generation, PgAioHandleState *state); +extern void pgaio_io_stage(PgAioHandle *ioh, PgAioOp op); +extern void pgaio_io_process_completion(PgAioHandle *ioh, int result); +extern void pgaio_io_prepare_submit(PgAioHandle *ioh); +extern bool pgaio_io_needs_synchronous_execution(PgAioHandle *ioh); +extern const char *pgaio_io_get_state_name(PgAioHandle *ioh); +extern void pgaio_shutdown(int code, Datum arg); + +/* aio_callback.c */ +extern void pgaio_io_call_stage(PgAioHandle *ioh); +extern void pgaio_io_call_complete_shared(PgAioHandle *ioh); +extern void pgaio_io_call_complete_local(PgAioHandle *ioh); + +/* aio_io.c */ +extern void pgaio_io_perform_synchronously(PgAioHandle *ioh); +extern const char *pgaio_io_get_op_name(PgAioHandle *ioh); + +/* aio_target.c */ +extern bool pgaio_io_can_reopen(PgAioHandle *ioh); +extern void pgaio_io_reopen(PgAioHandle *ioh); +extern const char *pgaio_io_get_target_name(PgAioHandle *ioh); + + +/* + * The AIO subsystem has fairly verbose debug logging support. This can be + * enabled/disabled at buildtime. The reason for this is that + * a) the verbosity can make debugging things on higher levels hard + * b) even if logging can be skipped due to elevel checks, it still causes a + * measurable slowdown + */ +#define PGAIO_VERBOSE 1 + +/* + * Simple ereport() wrapper that only logs if PGAIO_VERBOSE is defined. + * + * This intentionally still compiles the code, guarded by a constant if (0), + * if verbose logging is disabled, to make it less likely that debug logging + * is silently broken. + * + * The current definition requires passing at least one argument. + */ +#define pgaio_debug(elevel, msg, ...) \ + do { \ + if (PGAIO_VERBOSE) \ + ereport(elevel, \ + errhidestmt(true), errhidecontext(true), \ + errmsg_internal(msg, \ + __VA_ARGS__)); \ + } while(0) + +/* + * Simple ereport() wrapper. Note that the definition requires passing at + * least one argument. + */ +#define pgaio_debug_io(elevel, ioh, msg, ...) \ + pgaio_debug(elevel, "io %-10d|op %-5s|target %-4s|state %-16s: " msg, \ + pgaio_io_get_id(ioh), \ + pgaio_io_get_op_name(ioh), \ + pgaio_io_get_target_name(ioh), \ + pgaio_io_get_state_name(ioh), \ + __VA_ARGS__) + + +/* Declarations for the tables of function pointers exposed by each IO method. */ +extern PGDLLIMPORT const IoMethodOps pgaio_sync_ops; + +extern PGDLLIMPORT const IoMethodOps *pgaio_method_ops; +extern PGDLLIMPORT PgAioCtl *pgaio_ctl; +extern PGDLLIMPORT PgAioBackend *pgaio_my_backend; + + + +#endif /* AIO_INTERNAL_H */ diff --git a/src/include/storage/aio_types.h b/src/include/storage/aio_types.h new file mode 100644 index 00000000000..d2617139a25 --- /dev/null +++ b/src/include/storage/aio_types.h @@ -0,0 +1,115 @@ +/*------------------------------------------------------------------------- + * + * aio_types.h + * AIO related types that are useful to include separately, to reduce the + * "include burden". + * + * + * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/storage/aio_types.h + * + *------------------------------------------------------------------------- + */ +#ifndef AIO_TYPES_H +#define AIO_TYPES_H + +#include "storage/block.h" +#include "storage/relfilelocator.h" + + +typedef struct PgAioHandle PgAioHandle; + +/* + * A reference to an IO that can be used to wait for the IO (using + * pgaio_wref_wait()) to complete. + * + * These can be passed across process boundaries. + */ +typedef struct PgAioWaitRef +{ + /* internal ID identifying the specific PgAioHandle */ + uint32 aio_index; + + /* + * IO handles are reused. To detect if a handle was reused, and thereby + * avoid unnecessarily waiting for a newer IO, each time the handle is + * reused a generation number is increased. + * + * To avoid requiring alignment sufficient for an int64, split the + * generation into two. + */ + uint32 generation_upper; + uint32 generation_lower; +} PgAioWaitRef; + + +/* + * Information identifying what the IO is being performed on. + * + * This needs sufficient information to + * + * a) Reopen the file for the IO if the IO is executed in a context that + * cannot use the FD provided initially (e.g. because the IO is executed in + * a worker process). + * + * b) Describe the object the IO is performed on in log / error messages. + */ +typedef union PgAioTargetData +{ + /* just as an example placeholder for later */ + struct + { + uint32 queue_id; + } wal; +} PgAioTargetData; + + +/* + * The status of an AIO operation. + */ +typedef enum PgAioResultStatus +{ + ARS_UNKNOWN, /* not yet completed / uninitialized */ + ARS_OK, + ARS_PARTIAL, /* did not fully succeed, but no error */ + ARS_ERROR, +} PgAioResultStatus; + + +/* + * Result of IO operation, visible only to the initiator of IO. + */ +typedef struct PgAioResult +{ + /* + * This is of type PgAioHandleCallbackID, but can't use a bitfield of an + * enum, because some compilers treat enums as signed. + */ + uint32 id:8; + + /* of type PgAioResultStatus, see above */ + uint32 status:2; + + /* meaning defined by callback->error */ + uint32 error_data:22; + + int32 result; +} PgAioResult; + + +/* + * Combination of PgAioResult with minimal metadata about the IO. + * + * Contains sufficient information to be able, in case the IO [partially] + * fails, to log/raise an error under control of the IO issuing code. + */ +typedef struct PgAioReturn +{ + PgAioResult result; + PgAioTargetData target_data; +} PgAioReturn; + + +#endif /* AIO_TYPES_H */ diff --git a/src/include/utils/resowner.h b/src/include/utils/resowner.h index e8d452ca7ee..aede4bfc820 100644 --- a/src/include/utils/resowner.h +++ b/src/include/utils/resowner.h @@ -164,4 +164,9 @@ struct LOCALLOCK; extern void ResourceOwnerRememberLock(ResourceOwner owner, struct LOCALLOCK *locallock); extern void ResourceOwnerForgetLock(ResourceOwner owner, struct LOCALLOCK *locallock); +/* special support for AIO */ +struct dlist_node; +extern void ResourceOwnerRememberAioHandle(ResourceOwner owner, struct dlist_node *ioh_node); +extern void ResourceOwnerForgetAioHandle(ResourceOwner owner, struct dlist_node *ioh_node); + #endif /* RESOWNER_H */ diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index d331ab90d78..a252c3a81b4 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -51,6 +51,7 @@ #include "replication/origin.h" #include "replication/snapbuild.h" #include "replication/syncrep.h" +#include "storage/aio.h" #include "storage/condition_variable.h" #include "storage/fd.h" #include "storage/lmgr.h" @@ -2475,6 +2476,8 @@ CommitTransaction(void) AtEOXact_LogicalRepWorkers(true); pgstat_report_xact_timestamp(0); + pgaio_at_xact_end( /* is_subxact = */ false, /* is_commit = */ true); + ResourceOwnerDelete(TopTransactionResourceOwner); s->curTransactionOwner = NULL; CurTransactionResourceOwner = NULL; @@ -2988,6 +2991,8 @@ AbortTransaction(void) pgstat_report_xact_timestamp(0); } + pgaio_at_xact_end( /* is_subxact = */ false, /* is_commit = */ false); + /* * State remains TRANS_ABORT until CleanupTransaction(). */ @@ -5185,6 +5190,8 @@ CommitSubTransaction(void) AtEOSubXact_PgStat(true, s->nestingLevel); AtSubCommit_Snapshot(s->nestingLevel); + pgaio_at_xact_end( /* is_subxact = */ true, /* is_commit = */ true); + /* * We need to restore the upper transaction's read-only state, in case the * upper is read-write while the child is read-only; GUC will incorrectly @@ -5351,6 +5358,8 @@ AbortSubTransaction(void) AtSubAbort_Snapshot(s->nestingLevel); } + pgaio_at_xact_end( /* is_subxact = */ true, /* is_commit = */ false); + /* * Restore the upper transaction's read-only state, too. This should be * redundant with GUC's cleanup but we may as well do it for consistency diff --git a/src/backend/storage/aio/Makefile b/src/backend/storage/aio/Makefile index eaeaeeee8e3..89f821ea7e1 100644 --- a/src/backend/storage/aio/Makefile +++ b/src/backend/storage/aio/Makefile @@ -10,7 +10,11 @@ include $(top_builddir)/src/Makefile.global OBJS = \ aio.o \ + aio_callback.o \ aio_init.o \ + aio_io.o \ + aio_target.o \ + method_sync.o \ read_stream.o include $(top_srcdir)/src/backend/common.mk diff --git a/src/backend/storage/aio/aio.c b/src/backend/storage/aio/aio.c index f68cbc2b3f4..cefa888884c 100644 --- a/src/backend/storage/aio/aio.c +++ b/src/backend/storage/aio/aio.c @@ -3,6 +3,28 @@ * aio.c * AIO - Core Logic * + * For documentation about how AIO works on a higher level, including a + * schematic example, see README.md. + * + * + * AIO is a complicated subsystem. To keep things navigable it is split across + * a number of files: + * + * - method_*.c - different ways of executing AIO (e.g. worker process) + * + * - aio_target.c - IO on different kinds of targets + * + * - aio_io.c - method-independent code for specific IO ops (e.g. readv) + * + * - aio_callback.c - callbacks at IO operation lifecycle events + * + * - aio_init.c - per-server and per-backend initialization + * + * - aio.c - all other topics + * + * - read_stream.c - helper for reading buffered relation data + * + * * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * @@ -14,8 +36,22 @@ #include "postgres.h" +#include "miscadmin.h" +#include "port/atomics.h" #include "storage/aio.h" +#include "storage/aio_internal.h" #include "utils/guc.h" +#include "utils/resowner.h" +#include "utils/wait_event_types.h" + + +static inline void pgaio_io_update_state(PgAioHandle *ioh, PgAioHandleState new_state); +static void pgaio_io_reclaim(PgAioHandle *ioh); +static void pgaio_io_resowner_register(PgAioHandle *ioh); +static void pgaio_io_wait_for_free(void); +static PgAioHandle *pgaio_io_from_wref(PgAioWaitRef *iow, uint64 *ref_generation); +static const char *pgaio_io_state_get_name(PgAioHandleState s); +static void pgaio_io_wait(PgAioHandle *ioh, uint64 ref_generation); /* Options for io_method. */ @@ -28,9 +64,877 @@ const struct config_enum_entry io_method_options[] = { int io_method = DEFAULT_IO_METHOD; int io_max_concurrency = -1; +/* global control for AIO */ +PgAioCtl *pgaio_ctl; +/* current backend's per-backend state */ +PgAioBackend *pgaio_my_backend; + + +static const IoMethodOps *const pgaio_method_ops_table[] = { + [IOMETHOD_SYNC] = &pgaio_sync_ops, +}; + +/* callbacks for the configured io_method, set by assign_io_method */ +const IoMethodOps *pgaio_method_ops; + + + +/* -------------------------------------------------------------------------------- + * Public Functions related to PgAioHandle + * -------------------------------------------------------------------------------- + */ + +/* + * Acquire an AioHandle, waiting for IO completion if necessary. + * + * Each backend can only have one AIO handle that that has been "handed out" + * to code, but not yet submitted or released. This restriction is necessary + * to ensure that it is possible for code to wait for an unused handle by + * waiting for in-flight IO to complete. There is a limited number of handles + * in each backend, if multiple handles could be handed out without being + * submitted, waiting for all in-flight IO to complete would not guarantee + * that handles free up. + * + * It is cheap to acquire an IO handle, unless all handles are in use. In that + * case this function waits for the oldest IO to complete. In case that is not + * desirable, see pgaio_io_acquire_nb(). + * + * If a handle was acquired but then does not turn out to be needed, + * e.g. because pgaio_io_acquire() is called before starting an IO in a + * critical section, the handle needs to be released with pgaio_io_release(). + * + * + * To react to the completion of the IO as soon as it is known to have + * completed, callbacks can be registered with pgaio_io_register_callbacks(). + * + * To actually execute IO using the returned handle, the pgaio_io_prep_*() + * family of functions is used. In many cases the pgaio_io_prep_*() call will + * not be done directly by code that acquired the handle, but by lower level + * code that gets passed the handle. E.g. if code in bufmgr.c wants to perform + * AIO, it typically will pass the handle to smgr., which will pass it on to + * md.c, on to fd.c, which then finally calls pgaio_io_prep_*(). This + * forwarding allows the various layers to react to the IO's completion by + * registering callbacks. These callbacks in turn can translate a lower + * layer's result into a result understandable by a higher layer. + * + * Once pgaio_io_prep_*() is called, the IO may be in the process of being + * executed and might even complete before the functions return. That is, + * however, not guaranteed, to allow IO submission to be batched. To guarantee + * IO submission pgaio_submit_staged() needs to be called. + * + * After pgaio_io_prep_*() the AioHandle is "consumed" and may not be + * referenced by the IO issuing code. To e.g. wait for IO, references to the + * IO can be established with pgaio_io_get_wref() *before* pgaio_io_prep_*() + * is called. pgaio_wref_wait() can be used to wait for the IO to complete. + * + * + * To know if the IO [partially] succeeded or failed, a PgAioReturn * can be + * passed to pgaio_io_acquire(). Once the issuing backend has called + * pgaio_wref_wait(), the PgAioReturn contains information about whether the + * operation succeeded and details about the first failure, if any. The error + * can be raised / logged with pgaio_result_report(). + * + * The lifetime of the memory pointed to be *ret needs to be at least as long + * as the passed in resowner. If the resowner releases resources before the IO + * completes (typically due to an error), the reference to *ret will be + * cleared. In case of resowner cleanup *ret will not be updated with the + * results of the IO operation. + */ +PgAioHandle * +pgaio_io_acquire(struct ResourceOwnerData *resowner, PgAioReturn *ret) +{ + PgAioHandle *h; + + while (true) + { + h = pgaio_io_acquire_nb(resowner, ret); + + if (h != NULL) + return h; + + /* + * Evidently all handles by this backend are in use. Just wait for + * some to complete. + */ + pgaio_io_wait_for_free(); + } +} + +/* + * Acquire an AioHandle, returning NULL if no handles are free. + * + * See pgaio_io_acquire(). The only difference is that this function will return + * NULL if there are no idle handles, instead of blocking. + */ +PgAioHandle * +pgaio_io_acquire_nb(struct ResourceOwnerData *resowner, PgAioReturn *ret) +{ + if (pgaio_my_backend->num_staged_ios >= PGAIO_SUBMIT_BATCH_SIZE) + { + Assert(pgaio_my_backend->num_staged_ios == PGAIO_SUBMIT_BATCH_SIZE); + pgaio_submit_staged(); + } + + if (pgaio_my_backend->handed_out_io) + { + ereport(ERROR, + errmsg("API violation: Only one IO can be handed out")); + } + + if (!dclist_is_empty(&pgaio_my_backend->idle_ios)) + { + dlist_node *ion = dclist_pop_head_node(&pgaio_my_backend->idle_ios); + PgAioHandle *ioh = dclist_container(PgAioHandle, node, ion); + + Assert(ioh->state == PGAIO_HS_IDLE); + Assert(ioh->owner_procno == MyProcNumber); + + pgaio_io_update_state(ioh, PGAIO_HS_HANDED_OUT); + pgaio_my_backend->handed_out_io = ioh; + + if (resowner) + pgaio_io_resowner_register(ioh); + + if (ret) + { + ioh->report_return = ret; + ret->result.status = ARS_UNKNOWN; + } + + return ioh; + } + + return NULL; +} + +/* + * Release IO handle that turned out to not be required. + * + * See pgaio_io_acquire() for more details. + */ +void +pgaio_io_release(PgAioHandle *ioh) +{ + if (ioh == pgaio_my_backend->handed_out_io) + { + Assert(ioh->state == PGAIO_HS_HANDED_OUT); + Assert(ioh->resowner); + + pgaio_my_backend->handed_out_io = NULL; + pgaio_io_reclaim(ioh); + } + else + { + elog(ERROR, "release in unexpected state"); + } +} + +/* + * Release IO handle during resource owner cleanup. + */ +void +pgaio_io_release_resowner(dlist_node *ioh_node, bool on_error) +{ + PgAioHandle *ioh = dlist_container(PgAioHandle, resowner_node, ioh_node); + + Assert(ioh->resowner); + + ResourceOwnerForgetAioHandle(ioh->resowner, &ioh->resowner_node); + ioh->resowner = NULL; + + switch (ioh->state) + { + case PGAIO_HS_IDLE: + elog(ERROR, "unexpected"); + break; + case PGAIO_HS_HANDED_OUT: + Assert(ioh == pgaio_my_backend->handed_out_io || pgaio_my_backend->handed_out_io == NULL); + + if (ioh == pgaio_my_backend->handed_out_io) + { + pgaio_my_backend->handed_out_io = NULL; + if (!on_error) + elog(WARNING, "leaked AIO handle"); + } + + pgaio_io_reclaim(ioh); + break; + case PGAIO_HS_DEFINED: + case PGAIO_HS_STAGED: + /* XXX: Should we warn about this when is_commit? */ + pgaio_submit_staged(); + break; + case PGAIO_HS_SUBMITTED: + case PGAIO_HS_COMPLETED_IO: + case PGAIO_HS_COMPLETED_SHARED: + case PGAIO_HS_COMPLETED_LOCAL: + /* this is expected to happen */ + break; + } + + /* + * Need to unregister the reporting of the IO's result, the memory it's + * referencing likely has gone away. + */ + if (ioh->report_return) + ioh->report_return = NULL; +} + +/* + * Add a [set of] flags to the IO. + * + * Note that this combines flags with already set flags, rather than set flags + * to explicitly the passed in parameters. This is to allow multiple callsites + * to set flags. + */ +void +pgaio_io_set_flag(PgAioHandle *ioh, PgAioHandleFlags flag) +{ + Assert(ioh->state == PGAIO_HS_HANDED_OUT); + + ioh->flags |= flag; +} + +int +pgaio_io_get_id(PgAioHandle *ioh) +{ + Assert(ioh >= pgaio_ctl->io_handles && + ioh < (pgaio_ctl->io_handles + pgaio_ctl->io_handle_count)); + return ioh - pgaio_ctl->io_handles; +} + +ProcNumber +pgaio_io_get_owner(PgAioHandle *ioh) +{ + return ioh->owner_procno; +} + +void +pgaio_io_get_wref(PgAioHandle *ioh, PgAioWaitRef *iow) +{ + Assert(ioh->state == PGAIO_HS_HANDED_OUT || + ioh->state == PGAIO_HS_DEFINED || + ioh->state == PGAIO_HS_STAGED); + Assert(ioh->generation != 0); + + iow->aio_index = ioh - pgaio_ctl->io_handles; + iow->generation_upper = (uint32) (ioh->generation >> 32); + iow->generation_lower = (uint32) ioh->generation; +} + + + +/* -------------------------------------------------------------------------------- + * Internal Functions related to PgAioHandle + * -------------------------------------------------------------------------------- + */ + +static inline void +pgaio_io_update_state(PgAioHandle *ioh, PgAioHandleState new_state) +{ + pgaio_debug_io(DEBUG4, ioh, + "updating state to %s", + pgaio_io_state_get_name(new_state)); + + /* + * Ensure the changes signified by the new state are visible before the + * new state becomes visible. + */ + pg_write_barrier(); + + ioh->state = new_state; +} + +static void +pgaio_io_resowner_register(PgAioHandle *ioh) +{ + Assert(!ioh->resowner); + Assert(CurrentResourceOwner); + + ResourceOwnerRememberAioHandle(CurrentResourceOwner, &ioh->resowner_node); + ioh->resowner = CurrentResourceOwner; +} + +/* + * Should only be called from pgaio_io_prep_*(). + */ +void +pgaio_io_stage(PgAioHandle *ioh, PgAioOp op) +{ + bool needs_synchronous; + + Assert(ioh->state == PGAIO_HS_HANDED_OUT); + Assert(pgaio_io_has_target(ioh)); + + ioh->op = op; + ioh->result = 0; + + pgaio_io_update_state(ioh, PGAIO_HS_DEFINED); + + /* allow a new IO to be staged */ + pgaio_my_backend->handed_out_io = NULL; + + pgaio_io_call_stage(ioh); + + pgaio_io_update_state(ioh, PGAIO_HS_STAGED); + + needs_synchronous = pgaio_io_needs_synchronous_execution(ioh); + + pgaio_debug_io(DEBUG3, ioh, + "prepared, executing synchronously: %d", + needs_synchronous); + + if (!needs_synchronous) + { + pgaio_my_backend->staged_ios[pgaio_my_backend->num_staged_ios++] = ioh; + Assert(pgaio_my_backend->num_staged_ios <= PGAIO_SUBMIT_BATCH_SIZE); + } + else + { + pgaio_io_prepare_submit(ioh); + pgaio_io_perform_synchronously(ioh); + } +} + +bool +pgaio_io_needs_synchronous_execution(PgAioHandle *ioh) +{ + if (ioh->flags & PGAIO_HF_SYNCHRONOUS) + { + /* XXX: should we also check if there are other IOs staged? */ + return true; + } + + if (pgaio_method_ops->needs_synchronous_execution) + return pgaio_method_ops->needs_synchronous_execution(ioh); + return false; +} + +/* + * Handle IO being processed by IO method. + * + * Should be called by IO methods / synchronous IO execution, just before the + * IO is performed. + */ +void +pgaio_io_prepare_submit(PgAioHandle *ioh) +{ + pgaio_io_update_state(ioh, PGAIO_HS_SUBMITTED); + + dclist_push_tail(&pgaio_my_backend->in_flight_ios, &ioh->node); +} + +/* + * Handle IO getting completed by a method. + * + * Should be called by IO methods / synchronous IO execution + */ +void +pgaio_io_process_completion(PgAioHandle *ioh, int result) +{ + Assert(ioh->state == PGAIO_HS_SUBMITTED); + + ioh->result = result; + + pgaio_io_update_state(ioh, PGAIO_HS_COMPLETED_IO); + + pgaio_io_call_complete_shared(ioh); + + pgaio_io_update_state(ioh, PGAIO_HS_COMPLETED_SHARED); + + /* condition variable broadcast ensures state is visible before wakeup */ + ConditionVariableBroadcast(&ioh->cv); + + if (ioh->owner_procno == MyProcNumber) + pgaio_io_reclaim(ioh); +} + +bool +pgaio_io_was_recycled(PgAioHandle *ioh, uint64 ref_generation, PgAioHandleState *state) +{ + *state = ioh->state; + pg_read_barrier(); + + return ioh->generation != ref_generation; +} + +/* + * Wait for IO to complete. External code should never use this, outside of + * the AIO subsystem waits are only allowed via pgaio_wref_wait(). + */ +static void +pgaio_io_wait(PgAioHandle *ioh, uint64 ref_generation) +{ + PgAioHandleState state; + bool am_owner; + + am_owner = ioh->owner_procno == MyProcNumber; + + if (pgaio_io_was_recycled(ioh, ref_generation, &state)) + return; + + if (am_owner) + { + if (state == PGAIO_HS_STAGED) + { + /* XXX: Arguably this should be prevented by callers? */ + pgaio_submit_staged(); + } + else if (state != PGAIO_HS_SUBMITTED + && state != PGAIO_HS_COMPLETED_IO + && state != PGAIO_HS_COMPLETED_SHARED + && state != PGAIO_HS_COMPLETED_LOCAL) + { + elog(PANIC, "waiting for own IO in wrong state: %d", + state); + } + } + + while (true) + { + if (pgaio_io_was_recycled(ioh, ref_generation, &state)) + return; + + switch (state) + { + case PGAIO_HS_IDLE: + case PGAIO_HS_HANDED_OUT: + elog(ERROR, "IO in wrong state: %d", state); + break; + + case PGAIO_HS_SUBMITTED: + + /* + * If we need to wait via the IO method, do so now. Don't + * check via the IO method if the issuing backend is executing + * the IO synchronously. + */ + if (pgaio_method_ops->wait_one && !(ioh->flags & PGAIO_HF_SYNCHRONOUS)) + { + pgaio_method_ops->wait_one(ioh, ref_generation); + continue; + } + /* fallthrough */ + + /* waiting for owner to submit */ + case PGAIO_HS_DEFINED: + case PGAIO_HS_STAGED: + /* waiting for reaper to complete */ + /* fallthrough */ + case PGAIO_HS_COMPLETED_IO: + /* shouldn't be able to hit this otherwise */ + Assert(IsUnderPostmaster); + /* ensure we're going to get woken up */ + ConditionVariablePrepareToSleep(&ioh->cv); + + while (!pgaio_io_was_recycled(ioh, ref_generation, &state)) + { + if (state == PGAIO_HS_COMPLETED_SHARED || + state == PGAIO_HS_COMPLETED_LOCAL) + break; + ConditionVariableSleep(&ioh->cv, WAIT_EVENT_AIO_COMPLETION); + } + + ConditionVariableCancelSleep(); + break; + + case PGAIO_HS_COMPLETED_SHARED: + case PGAIO_HS_COMPLETED_LOCAL: + /* see above */ + if (am_owner) + pgaio_io_reclaim(ioh); + return; + } + } +} + +static void +pgaio_io_reclaim(PgAioHandle *ioh) +{ + /* This is only ok if it's our IO */ + Assert(ioh->owner_procno == MyProcNumber); + + pgaio_debug_io(DEBUG4, ioh, + "reclaiming, result: %d, distilled_result: AFIXME, report to: %p", + ioh->result, + ioh->report_return); + + if (ioh->state == PGAIO_HS_COMPLETED_SHARED) + { + pgaio_io_call_complete_local(ioh); + pgaio_io_update_state(ioh, PGAIO_HS_COMPLETED_LOCAL); + } + + /* if the IO has been defined, we might need to do more work */ + if (ioh->state != PGAIO_HS_HANDED_OUT) + { + dclist_delete_from(&pgaio_my_backend->in_flight_ios, &ioh->node); + + if (ioh->report_return) + { + ioh->report_return->result = ioh->distilled_result; + ioh->report_return->target_data = ioh->target_data; + } + } + + if (ioh->resowner) + { + ResourceOwnerForgetAioHandle(ioh->resowner, &ioh->resowner_node); + ioh->resowner = NULL; + } + + Assert(!ioh->resowner); + + ioh->op = PGAIO_OP_INVALID; + ioh->target = PGAIO_TID_INVALID; + ioh->flags = 0; + ioh->num_shared_callbacks = 0; + ioh->handle_data_len = 0; + ioh->report_return = NULL; + ioh->result = 0; + ioh->distilled_result.status = ARS_UNKNOWN; + + /* XXX: the barrier is probably superfluous */ + pg_write_barrier(); + ioh->generation++; + + pgaio_io_update_state(ioh, PGAIO_HS_IDLE); + + /* + * We push the IO to the head of the idle IO list, that seems more cache + * efficient in cases where only a few IOs are used. + */ + dclist_push_head(&pgaio_my_backend->idle_ios, &ioh->node); +} + +static void +pgaio_io_wait_for_free(void) +{ + int reclaimed = 0; + + pgaio_debug(DEBUG2, "waiting for self with %d pending", + pgaio_my_backend->num_staged_ios); + + /* + * First check if any of our IOs actually have completed - when using + * worker, that'll often be the case. We could do so as part of the loop + * below, but that'd potentially lead us to wait for some IO submitted + * before. + */ + for (int i = 0; i < io_max_concurrency; i++) + { + PgAioHandle *ioh = &pgaio_ctl->io_handles[pgaio_my_backend->io_handle_off + i]; + + if (ioh->state == PGAIO_HS_COMPLETED_SHARED) + { + pgaio_io_reclaim(ioh); + reclaimed++; + } + } + + if (reclaimed > 0) + return; + + /* + * If we have any unsubmitted IOs, submit them now. We'll start waiting in + * a second, so it's better they're in flight. This also addresses the + * edge-case that all IOs are unsubmitted. + */ + if (pgaio_my_backend->num_staged_ios > 0) + { + pgaio_submit_staged(); + } + + /* + * It's possible that we recognized there were free IOs while submitting. + */ + if (dclist_count(&pgaio_my_backend->in_flight_ios) == 0) + { + elog(ERROR, "no free IOs despite no in-flight IOs"); + } + + /* + * Wait for the oldest in-flight IO to complete. + * + * XXX: Reusing the general IO wait is suboptimal, we don't need to wait + * for that specific IO to complete, we just need *any* IO to complete. + */ + { + PgAioHandle *ioh = dclist_head_element(PgAioHandle, node, &pgaio_my_backend->in_flight_ios); + + switch (ioh->state) + { + /* should not be in in-flight list */ + case PGAIO_HS_IDLE: + case PGAIO_HS_DEFINED: + case PGAIO_HS_HANDED_OUT: + case PGAIO_HS_STAGED: + case PGAIO_HS_COMPLETED_LOCAL: + elog(ERROR, "shouldn't get here with io:%d in state %d", + pgaio_io_get_id(ioh), ioh->state); + break; + + case PGAIO_HS_COMPLETED_IO: + case PGAIO_HS_SUBMITTED: + pgaio_debug_io(DEBUG2, ioh, + "waiting for free io with %d in flight", + dclist_count(&pgaio_my_backend->in_flight_ios)); + + /* + * In a more general case this would be racy, because the + * generation could increase after we read ioh->state above. + * But we are only looking at IOs by the current backend and + * the IO can only be recycled by this backend. + */ + pgaio_io_wait(ioh, ioh->generation); + break; + + case PGAIO_HS_COMPLETED_SHARED: + /* it's possible that another backend just finished this IO */ + pgaio_io_reclaim(ioh); + break; + } + + if (dclist_count(&pgaio_my_backend->idle_ios) == 0) + elog(PANIC, "no idle IOs after waiting"); + return; + } +} + +/* + * Internal - code outside of AIO should never need this and it'd be hard for + * such code to be safe. + */ +static PgAioHandle * +pgaio_io_from_wref(PgAioWaitRef *iow, uint64 *ref_generation) +{ + PgAioHandle *ioh; + + Assert(iow->aio_index < pgaio_ctl->io_handle_count); + + ioh = &pgaio_ctl->io_handles[iow->aio_index]; + + *ref_generation = ((uint64) iow->generation_upper) << 32 | + iow->generation_lower; + + Assert(*ref_generation != 0); + + return ioh; +} + +static const char * +pgaio_io_state_get_name(PgAioHandleState s) +{ +#define PGAIO_HS_TOSTR_CASE(sym) case PGAIO_HS_##sym: return #sym + switch (s) + { + PGAIO_HS_TOSTR_CASE(IDLE); + PGAIO_HS_TOSTR_CASE(HANDED_OUT); + PGAIO_HS_TOSTR_CASE(DEFINED); + PGAIO_HS_TOSTR_CASE(STAGED); + PGAIO_HS_TOSTR_CASE(SUBMITTED); + PGAIO_HS_TOSTR_CASE(COMPLETED_IO); + PGAIO_HS_TOSTR_CASE(COMPLETED_SHARED); + PGAIO_HS_TOSTR_CASE(COMPLETED_LOCAL); + } +#undef PGAIO_HS_TOSTR_CASE + + return NULL; /* silence compiler */ +} + +const char * +pgaio_io_get_state_name(PgAioHandle *ioh) +{ + return pgaio_io_state_get_name(ioh->state); +} + + + +/* -------------------------------------------------------------------------------- + * Functions primarily related to IO Wait References + * -------------------------------------------------------------------------------- + */ + +void +pgaio_wref_clear(PgAioWaitRef *iow) +{ + iow->aio_index = PG_UINT32_MAX; +} + +bool +pgaio_wref_valid(PgAioWaitRef *iow) +{ + return iow->aio_index != PG_UINT32_MAX; +} + +int +pgaio_wref_get_id(PgAioWaitRef *iow) +{ + Assert(pgaio_wref_valid(iow)); + return iow->aio_index; +} + +/* + * Wait for the IO to have completed. + */ +void +pgaio_wref_wait(PgAioWaitRef *iow) +{ + uint64 ref_generation; + PgAioHandle *ioh; + + ioh = pgaio_io_from_wref(iow, &ref_generation); + + pgaio_io_wait(ioh, ref_generation); +} + +/* + * Check if the the referenced IO completed, without blocking. + */ +bool +pgaio_wref_check_done(PgAioWaitRef *iow) +{ + uint64 ref_generation; + PgAioHandleState state; + bool am_owner; + PgAioHandle *ioh; + + ioh = pgaio_io_from_wref(iow, &ref_generation); + + if (pgaio_io_was_recycled(ioh, ref_generation, &state)) + return true; + + if (state == PGAIO_HS_IDLE) + return true; + + am_owner = ioh->owner_procno == MyProcNumber; + + if (state == PGAIO_HS_COMPLETED_SHARED || + state == PGAIO_HS_COMPLETED_LOCAL) + { + if (am_owner) + pgaio_io_reclaim(ioh); + return true; + } + + return false; +} + + + +/* -------------------------------------------------------------------------------- + * Actions on multiple IOs. + * -------------------------------------------------------------------------------- + */ + +void +pgaio_submit_staged(void) +{ + int total_submitted = 0; + int did_submit; + + if (pgaio_my_backend->num_staged_ios == 0) + return; + + + START_CRIT_SECTION(); + + did_submit = pgaio_method_ops->submit(pgaio_my_backend->num_staged_ios, + pgaio_my_backend->staged_ios); + + END_CRIT_SECTION(); + + total_submitted += did_submit; + + Assert(total_submitted == did_submit); + + pgaio_my_backend->num_staged_ios = 0; + + pgaio_debug(DEBUG4, + "aio: submitted %d IOs", + total_submitted); +} + +bool +pgaio_have_staged(void) +{ + return pgaio_my_backend->num_staged_ios > 0; +} + + + +/* -------------------------------------------------------------------------------- + * Other + * -------------------------------------------------------------------------------- + */ + +/* + * Need to submit staged but not yet submitted IOs using the fd, otherwise + * the IO would end up targeting something bogus. + */ +void +pgaio_closing_fd(int fd) +{ + /* + * Might be called before AIO is initialized or in a subprocess that + * doesn't use AIO. + */ + if (!pgaio_my_backend) + return; + + /* + * For now just submit all staged IOs - we could be more selective, but + * it's probably not worth it. + */ + pgaio_submit_staged(); +} + +void +pgaio_at_xact_end(bool is_subxact, bool is_commit) +{ + Assert(!pgaio_my_backend->handed_out_io); +} + +/* + * Similar to pgaio_at_xact_end(..., is_commit = false), but for cases where + * errors happen outside of transactions. + */ +void +pgaio_at_error(void) +{ + Assert(!pgaio_my_backend->handed_out_io); +} + +void +pgaio_shutdown(int code, Datum arg) +{ + Assert(pgaio_my_backend); + Assert(!pgaio_my_backend->handed_out_io); + + /* + * Before exiting, make sure that all IOs are finished. That has two main + * purposes: - it's somewhat annoying to see partially finished IOs in + * stats views etc - it's rumored that some kernel-level AIO mechanisms + * don't deal well with the issuer of an AIO exiting + */ + + while (!dclist_is_empty(&pgaio_my_backend->in_flight_ios)) + { + PgAioHandle *ioh = dclist_head_element(PgAioHandle, node, &pgaio_my_backend->in_flight_ios); + + /* see comment in pgaio_io_wait_for_free() about raciness */ + pgaio_io_wait(ioh, ioh->generation); + } + + pgaio_my_backend = NULL; +} void assign_io_method(int newval, void *extra) { + Assert(pgaio_method_ops_table[newval] != NULL); + Assert(newval < lengthof(io_method_options)); + + pgaio_method_ops = pgaio_method_ops_table[newval]; } diff --git a/src/backend/storage/aio/aio_callback.c b/src/backend/storage/aio/aio_callback.c new file mode 100644 index 00000000000..93f71690169 --- /dev/null +++ b/src/backend/storage/aio/aio_callback.c @@ -0,0 +1,280 @@ +/*------------------------------------------------------------------------- + * + * aio_callback.c + * AIO - Functionality related to callbacks that can be registered on IO + * Handles + * + * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * IDENTIFICATION + * src/backend/storage/aio/aio_callback.c + * + *------------------------------------------------------------------------- + */ + +#include "postgres.h" + +#include "miscadmin.h" +#include "storage/aio.h" +#include "storage/aio_internal.h" +#include "utils/memutils.h" + + +/* just to have something to put into the aio_handle_cbs */ +static const struct PgAioHandleCallbacks aio_invalid_cb = {0}; + +typedef struct PgAioHandleCallbacksEntry +{ + const PgAioHandleCallbacks *const cb; + const char *const name; +} PgAioHandleCallbacksEntry; + +/* + * Callback definition for the callbacks that can be registered on an IO + * handle. See PgAioHandleCallbackID's definition for an explanation for why + * callbacks are not identified by a pointer. + */ +static const PgAioHandleCallbacksEntry aio_handle_cbs[] = { +#define CALLBACK_ENTRY(id, callback) [id] = {.cb = &callback, .name = #callback} + CALLBACK_ENTRY(PGAIO_HCB_INVALID, aio_invalid_cb), +#undef CALLBACK_ENTRY +}; + + + +/* + * Register callback for the IO handle. + * + * Only a limited number (PGAIO_HANDLE_MAX_CALLBACKS) of callbacks can be + * registered for each IO. + * + * Callbacks need to be registered before [indirectly] calling + * pgaio_io_prep_*(), as the IO may be executed immediately. + * + * + * Note that callbacks are executed in critical sections. This is necessary + * to be able to execute IO in critical sections (consider e.g. WAL + * logging). To perform AIO we first need to acquire a handle, which, if there + * are no free handles, requires waiting for IOs to complete and to execute + * their completion callbacks. + * + * Callbacks may be executed in the issuing backend but also in another + * backend (because that backend is waiting for the IO) or in IO workers (if + * io_method=worker is used). + * + * + * See PgAioHandleCallbackID's definition for an explanation for why + * callbacks are not identified by a pointer. + */ +void +pgaio_io_register_callbacks(PgAioHandle *ioh, PgAioHandleCallbackID cbid) +{ + const PgAioHandleCallbacksEntry *ce = &aio_handle_cbs[cbid]; + + if (cbid >= lengthof(aio_handle_cbs)) + elog(ERROR, "callback %d is out of range", cbid); + if (aio_handle_cbs[cbid].cb->complete_shared == NULL && + aio_handle_cbs[cbid].cb->complete_local == NULL) + elog(ERROR, "callback %d does not have completion callback", cbid); + if (ioh->num_shared_callbacks >= PGAIO_HANDLE_MAX_CALLBACKS) + elog(PANIC, "too many callbacks, the max is %d", PGAIO_HANDLE_MAX_CALLBACKS); + ioh->shared_callbacks[ioh->num_shared_callbacks] = cbid; + + pgaio_debug_io(DEBUG3, ioh, + "adding cb #%d, id %d/%s", + ioh->num_shared_callbacks + 1, + cbid, ce->name); + + ioh->num_shared_callbacks++; +} + +/* + * Associate an array of data with the Handle. This is e.g. useful to the + * transport knowledge about which buffers a multi-block IO affects to + * completion callbacks. + * + * Right now this can be done only once for each IO, even though multiple + * callbacks can be registered. There aren't any known usecases requiring more + * and the required amount of shared memory does add up, so it doesn't seem + * worth multiplying memory usage by PGAIO_HANDLE_MAX_CALLBACKS. + */ +void +pgaio_io_set_handle_data_64(PgAioHandle *ioh, uint64 *data, uint8 len) +{ + Assert(ioh->state == PGAIO_HS_HANDED_OUT); + Assert(ioh->handle_data_len == 0); + Assert(len <= PG_IOV_MAX); + + for (int i = 0; i < len; i++) + pgaio_ctl->handle_data[ioh->iovec_off + i] = data[i]; + ioh->handle_data_len = len; +} + +/* + * Convenience version of pgaio_io_set_handle_data_64() that converts a 32bit + * array to a 64bit array. Without it callers would end up needing to + * open-code equivalent code. + */ +void +pgaio_io_set_handle_data_32(PgAioHandle *ioh, uint32 *data, uint8 len) +{ + Assert(ioh->state == PGAIO_HS_HANDED_OUT); + Assert(ioh->handle_data_len == 0); + Assert(len <= PG_IOV_MAX); + + for (int i = 0; i < len; i++) + pgaio_ctl->handle_data[ioh->iovec_off + i] = data[i]; + ioh->handle_data_len = len; +} + +/* + * Return data set with pgaio_io_set_handle_data_*(). + */ +uint64 * +pgaio_io_get_handle_data(PgAioHandle *ioh, uint8 *len) +{ + Assert(ioh->handle_data_len > 0); + + *len = ioh->handle_data_len; + + return &pgaio_ctl->handle_data[ioh->iovec_off]; +} + +/* + * Internal function which invokes ->stage for all the registered callbacks. + */ +void +pgaio_io_call_stage(PgAioHandle *ioh) +{ + Assert(ioh->target > PGAIO_TID_INVALID && ioh->target < PGAIO_TID_COUNT); + Assert(ioh->op > PGAIO_OP_INVALID && ioh->op < PGAIO_OP_COUNT); + + for (int i = ioh->num_shared_callbacks; i > 0; i--) + { + PgAioHandleCallbackID cbid = ioh->shared_callbacks[i - 1]; + const PgAioHandleCallbacksEntry *ce = &aio_handle_cbs[cbid]; + + if (!ce->cb->stage) + continue; + + pgaio_debug_io(DEBUG3, ioh, + "calling cb #%d %d/%s->stage", + i, cbid, ce->name); + ce->cb->stage(ioh); + } +} + +/* + * Internal function which invokes ->complete_shared for all the registered + * callbacks. + */ +void +pgaio_io_call_complete_shared(PgAioHandle *ioh) +{ + PgAioResult result; + + START_CRIT_SECTION(); + + Assert(ioh->target > PGAIO_TID_INVALID && ioh->target < PGAIO_TID_COUNT); + Assert(ioh->op > PGAIO_OP_INVALID && ioh->op < PGAIO_OP_COUNT); + + result.status = ARS_OK; /* low level IO is always considered OK */ + result.result = ioh->result; + result.id = PGAIO_HCB_INVALID; + result.error_data = 0; + + for (int i = ioh->num_shared_callbacks; i > 0; i--) + { + PgAioHandleCallbackID cbid = ioh->shared_callbacks[i - 1]; + const PgAioHandleCallbacksEntry *ce = &aio_handle_cbs[cbid]; + + if (!ce->cb->complete_shared) + continue; + + pgaio_debug_io(DEBUG3, ioh, + "calling cb #%d, id %d/%s->complete_shared with distilled result status %d, id %u, error_data: %d, result: %d", + i, cbid, ce->name, + result.status, result.id, result.error_data, result.result); + result = ce->cb->complete_shared(ioh, result); + } + + ioh->distilled_result = result; + + pgaio_debug_io(DEBUG3, ioh, + "distilled result status %d, id %u, error_data: %d, result: %d, raw_result %d", + result.status, result.id, result.error_data, result.result, + ioh->result); + + END_CRIT_SECTION(); +} + + +/* + * Internal function which invokes ->complete_local for all the registered + * callbacks. + * + * XXX: It'd be nice to deduplicate with pgaio_io_call_complete_shared(). + */ +void +pgaio_io_call_complete_local(PgAioHandle *ioh) +{ + PgAioResult result; + + START_CRIT_SECTION(); + + Assert(ioh->target > PGAIO_TID_INVALID && ioh->target < PGAIO_TID_COUNT); + Assert(ioh->op > PGAIO_OP_INVALID && ioh->op < PGAIO_OP_COUNT); + + /* start with distilled result from shared callback */ + result = ioh->distilled_result; + + for (int i = ioh->num_shared_callbacks; i > 0; i--) + { + PgAioHandleCallbackID cbid = ioh->shared_callbacks[i - 1]; + const PgAioHandleCallbacksEntry *ce = &aio_handle_cbs[cbid]; + + if (!ce->cb->complete_local) + continue; + + pgaio_debug_io(DEBUG3, ioh, + "calling cb #%d, id %d/%s->complete_local with distilled result status %d, id %u, error_data: %d, result: %d", + i, cbid, ce->name, + result.status, result.id, result.error_data, result.result); + result = ce->cb->complete_local(ioh, result); + } + + /* + * Note that we don't save the result in ioh->distilled_result, the local + * callback's result should not ever matter to other waiters. + */ + pgaio_debug_io(DEBUG3, ioh, + "distilled result status %d, id %u, error_data: %d, result: %d, raw_result %d", + result.status, result.id, result.error_data, result.result, + ioh->result); + + END_CRIT_SECTION(); +} + + + +/* -------------------------------------------------------------------------------- + * IO Result + * -------------------------------------------------------------------------------- + */ + +void +pgaio_result_report(PgAioResult result, const PgAioTargetData *target_data, int elevel) +{ + PgAioHandleCallbackID cbid = result.id; + const PgAioHandleCallbacksEntry *ce = &aio_handle_cbs[cbid]; + + Assert(result.status != ARS_UNKNOWN); + Assert(result.status != ARS_OK); + + if (ce->cb->report == NULL) + elog(ERROR, "callback %d/%s does not have report callback", + result.id, ce->name); + + ce->cb->report(result, target_data, elevel); +} diff --git a/src/backend/storage/aio/aio_init.c b/src/backend/storage/aio/aio_init.c index f7ee8270756..0e98cc0c8fb 100644 --- a/src/backend/storage/aio/aio_init.c +++ b/src/backend/storage/aio/aio_init.c @@ -14,24 +14,210 @@ #include "postgres.h" +#include "miscadmin.h" +#include "storage/aio.h" #include "storage/aio_init.h" +#include "storage/aio_internal.h" +#include "storage/ipc.h" +#include "storage/proc.h" +#include "storage/shmem.h" +#include "utils/guc.h" +static Size +AioCtlShmemSize(void) +{ + Size sz; + + /* pgaio_ctl itself */ + sz = offsetof(PgAioCtl, io_handles); + + return sz; +} + +static uint32 +AioProcs(void) +{ + return MaxBackends + NUM_AUXILIARY_PROCS; +} + +static Size +AioBackendShmemSize(void) +{ + return mul_size(AioProcs(), sizeof(PgAioBackend)); +} + +static Size +AioHandleShmemSize(void) +{ + Size sz; + + /* ios */ + sz = mul_size(AioProcs(), + mul_size(io_max_concurrency, sizeof(PgAioHandle))); + + return sz; +} + +static Size +AioHandleIOVShmemSize(void) +{ + return mul_size(sizeof(struct iovec), + mul_size(mul_size(PG_IOV_MAX, AioProcs()), + io_max_concurrency)); +} + +static Size +AioHandleDataShmemSize(void) +{ + return mul_size(sizeof(uint64), + mul_size(mul_size(PG_IOV_MAX, AioProcs()), + io_max_concurrency)); +} + +/* + * Choose a suitable value for io_max_concurrency. + * + * It's unlikely that we could have more IOs in flight than buffers that we + * would be allowed to pin. + * + * On the upper end, apply a cap too - just because shared_buffers is large, + * it doesn't make sense have millions of buffers undergo IO concurrently. + */ +static int +AioChooseMaxConccurrency(void) +{ + uint32 max_backends; + int max_proportional_pins; + + /* Similar logic to LimitAdditionalPins() */ + max_backends = MaxBackends + NUM_AUXILIARY_PROCS; + max_proportional_pins = NBuffers / max_backends; + + max_proportional_pins = Max(max_proportional_pins, 1); + + /* apply upper limit */ + return Min(max_proportional_pins, 64); +} + Size AioShmemSize(void) { Size sz = 0; + /* + * We prefer to report this value's source as PGC_S_DYNAMIC_DEFAULT. + * However, if the DBA explicitly set wal_buffers = -1 in the config file, + * then PGC_S_DYNAMIC_DEFAULT will fail to override that and we must force + * + */ + if (io_max_concurrency == -1) + { + char buf[32]; + + snprintf(buf, sizeof(buf), "%d", AioChooseMaxConccurrency()); + SetConfigOption("io_max_concurrency", buf, PGC_POSTMASTER, + PGC_S_DYNAMIC_DEFAULT); + if (io_max_concurrency == -1) /* failed to apply it? */ + SetConfigOption("io_max_concurrency", buf, PGC_POSTMASTER, + PGC_S_OVERRIDE); + } + + sz = add_size(sz, AioCtlShmemSize()); + sz = add_size(sz, AioBackendShmemSize()); + sz = add_size(sz, AioHandleShmemSize()); + sz = add_size(sz, AioHandleIOVShmemSize()); + sz = add_size(sz, AioHandleDataShmemSize()); + + if (pgaio_method_ops->shmem_size) + sz = add_size(sz, pgaio_method_ops->shmem_size()); + return sz; } void AioShmemInit(void) { + bool found; + uint32 io_handle_off = 0; + uint32 iovec_off = 0; + uint32 per_backend_iovecs = io_max_concurrency * PG_IOV_MAX; + + pgaio_ctl = (PgAioCtl *) + ShmemInitStruct("AioCtl", AioCtlShmemSize(), &found); + + if (found) + goto out; + + memset(pgaio_ctl, 0, AioCtlShmemSize()); + + pgaio_ctl->io_handle_count = AioProcs() * io_max_concurrency; + pgaio_ctl->iovec_count = AioProcs() * per_backend_iovecs; + + pgaio_ctl->backend_state = (PgAioBackend *) + ShmemInitStruct("AioBackend", AioBackendShmemSize(), &found); + + pgaio_ctl->io_handles = (PgAioHandle *) + ShmemInitStruct("AioHandle", AioHandleShmemSize(), &found); + + pgaio_ctl->iovecs = (struct iovec *) + ShmemInitStruct("AioHandleIOV", AioHandleIOVShmemSize(), &found); + pgaio_ctl->handle_data = (uint64 *) + ShmemInitStruct("AioHandleData", AioHandleDataShmemSize(), &found); + + for (int procno = 0; procno < AioProcs(); procno++) + { + PgAioBackend *bs = &pgaio_ctl->backend_state[procno]; + + bs->io_handle_off = io_handle_off; + io_handle_off += io_max_concurrency; + + dclist_init(&bs->idle_ios); + memset(bs->staged_ios, 0, sizeof(PgAioHandle *) * PGAIO_SUBMIT_BATCH_SIZE); + dclist_init(&bs->in_flight_ios); + + /* initialize per-backend IOs */ + for (int i = 0; i < io_max_concurrency; i++) + { + PgAioHandle *ioh = &pgaio_ctl->io_handles[bs->io_handle_off + i]; + + ioh->generation = 1; + ioh->owner_procno = procno; + ioh->iovec_off = iovec_off; + ioh->handle_data_len = 0; + ioh->report_return = NULL; + ioh->resowner = NULL; + ioh->num_shared_callbacks = 0; + ioh->distilled_result.status = ARS_UNKNOWN; + ioh->flags = 0; + + ConditionVariableInit(&ioh->cv); + + dclist_push_tail(&bs->idle_ios, &ioh->node); + iovec_off += PG_IOV_MAX; + } + } + +out: + /* Initialize IO method specific resources. */ + if (pgaio_method_ops->shmem_init) + pgaio_method_ops->shmem_init(!found); } void pgaio_init_backend(void) { + /* shouldn't be initialized twice */ + Assert(!pgaio_my_backend); + + if (MyProc == NULL || MyProcNumber >= AioProcs()) + elog(ERROR, "aio requires a normal PGPROC"); + + pgaio_my_backend = &pgaio_ctl->backend_state[MyProcNumber]; + + if (pgaio_method_ops->init_backend) + pgaio_method_ops->init_backend(); + + before_shmem_exit(pgaio_shutdown, 0); } diff --git a/src/backend/storage/aio/aio_io.c b/src/backend/storage/aio/aio_io.c new file mode 100644 index 00000000000..bb010d6152c --- /dev/null +++ b/src/backend/storage/aio/aio_io.c @@ -0,0 +1,175 @@ +/*------------------------------------------------------------------------- + * + * aio_io.c + * AIO - Low Level IO Handling + * + * Functions related to associating IO operations to IO Handles and IO-method + * independent support functions for actually performing IO. + * + * + * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * IDENTIFICATION + * src/backend/storage/aio/aio_io.c + * + *------------------------------------------------------------------------- + */ + +#include "postgres.h" + +#include "storage/aio.h" +#include "storage/aio_internal.h" +#include "storage/fd.h" +#include "utils/wait_event.h" + + +static void pgaio_io_before_prep(PgAioHandle *ioh); + + + +/* -------------------------------------------------------------------------------- + * Public IO related functions operating on IO Handles + * -------------------------------------------------------------------------------- + */ + +/* + * Scatter/gather IO needs to associate an iovec with the Handle. To support + * worker mode this data needs to be in shared memory. + * + * XXX: Right now the amount of space available for each IO is + * PG_IOV_MAX. While it's tempting to use the io_combine_limit GUC, that's + * PGC_USERSET, so we can't allocate shared memory based on that. + */ +int +pgaio_io_get_iovec(PgAioHandle *ioh, struct iovec **iov) +{ + Assert(ioh->state == PGAIO_HS_HANDED_OUT); + + *iov = &pgaio_ctl->iovecs[ioh->iovec_off]; + + return PG_IOV_MAX; +} + +PgAioOpData * +pgaio_io_get_op_data(PgAioHandle *ioh) +{ + return &ioh->op_data; +} + + + +/* -------------------------------------------------------------------------------- + * "Preparation" routines for individual IO operations + * + * These are called by the code actually initiating an IO, to associate the IO + * specific data with an AIO handle. + * + * Each of the preparation routines first needs to call + * pgaio_io_before_prep(), then fill IO specific fields in the handle and then + * finally call pgaio_io_stage(). + * -------------------------------------------------------------------------------- + */ + +void +pgaio_io_prep_readv(PgAioHandle *ioh, + int fd, int iovcnt, uint64 offset) +{ + pgaio_io_before_prep(ioh); + + ioh->op_data.read.fd = fd; + ioh->op_data.read.offset = offset; + ioh->op_data.read.iov_length = iovcnt; + + pgaio_io_stage(ioh, PGAIO_OP_READV); +} + +void +pgaio_io_prep_writev(PgAioHandle *ioh, + int fd, int iovcnt, uint64 offset) +{ + pgaio_io_before_prep(ioh); + + ioh->op_data.write.fd = fd; + ioh->op_data.write.offset = offset; + ioh->op_data.write.iov_length = iovcnt; + + pgaio_io_stage(ioh, PGAIO_OP_WRITEV); +} + + + +/* -------------------------------------------------------------------------------- + * Internal IO related functions operating on IO Handles + * -------------------------------------------------------------------------------- + */ + +/* + * Execute IO operation synchronously. This is implemented here, not in + * method_sync.c, because other IO methods lso might use it / fall back to it. + */ +void +pgaio_io_perform_synchronously(PgAioHandle *ioh) +{ + ssize_t result = 0; + struct iovec *iov = &pgaio_ctl->iovecs[ioh->iovec_off]; + + /* Perform IO. */ + switch (ioh->op) + { + case PGAIO_OP_READV: + pgstat_report_wait_start(WAIT_EVENT_DATA_FILE_READ); + result = pg_preadv(ioh->op_data.read.fd, iov, + ioh->op_data.read.iov_length, + ioh->op_data.read.offset); + pgstat_report_wait_end(); + break; + case PGAIO_OP_WRITEV: + pgstat_report_wait_start(WAIT_EVENT_DATA_FILE_WRITE); + result = pg_pwritev(ioh->op_data.write.fd, iov, + ioh->op_data.write.iov_length, + ioh->op_data.write.offset); + pgstat_report_wait_end(); + break; + case PGAIO_OP_INVALID: + elog(ERROR, "trying to execute invalid IO operation"); + } + + ioh->result = result < 0 ? -errno : result; + + pgaio_io_process_completion(ioh, ioh->result); +} + +/* + * Helper function to be called by IO operation preparation functions, before + * any data in the handle is set. Mostly to centralize assertions. + */ +static void +pgaio_io_before_prep(PgAioHandle *ioh) +{ + Assert(ioh->state == PGAIO_HS_HANDED_OUT); + Assert(pgaio_io_has_target(ioh)); + Assert(ioh->op == PGAIO_OP_INVALID); +} + +/* + * Could be made part of the public interface, but it's not clear there's + * really a use case for that. + */ +const char * +pgaio_io_get_op_name(PgAioHandle *ioh) +{ + Assert(ioh->op >= 0 && ioh->op < PGAIO_OP_COUNT); + + switch (ioh->op) + { + case PGAIO_OP_INVALID: + return "invalid"; + case PGAIO_OP_READV: + return "read"; + case PGAIO_OP_WRITEV: + return "write"; + } + + return NULL; /* silence compiler */ +} diff --git a/src/backend/storage/aio/aio_target.c b/src/backend/storage/aio/aio_target.c new file mode 100644 index 00000000000..15428968e58 --- /dev/null +++ b/src/backend/storage/aio/aio_target.c @@ -0,0 +1,108 @@ +/*------------------------------------------------------------------------- + * + * aio_target.c + * AIO - Functionality related to executing IO for different targets + * + * XXX Write me + * + * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * IDENTIFICATION + * src/backend/storage/aio/aio_target.c + * + *------------------------------------------------------------------------- + */ + +#include "postgres.h" + +#include "storage/aio.h" +#include "storage/aio_internal.h" + + +/* + * Registry for entities that can be the target of AIO. + * + * To support executing using worker processes, the file descriptor for an IO + * may need to be be reopened in a different process. This is done via the + * PgAioTargetInfo.reopen callback. + */ +static const PgAioTargetInfo *pgaio_target_info[] = { + [PGAIO_TID_INVALID] = &(PgAioTargetInfo) { + .name = "invalid", + }, +}; + + + +bool +pgaio_io_has_target(PgAioHandle *ioh) +{ + return ioh->target != PGAIO_TID_INVALID; +} + +/* + * Return the name for the target associated with the IO. Mostly useful for + * debugging/logging. + */ +const char * +pgaio_io_get_target_name(PgAioHandle *ioh) +{ + Assert(ioh->target >= 0 && ioh->target < PGAIO_TID_COUNT); + + return pgaio_target_info[ioh->target]->name; +} + +/* + * Assign a target to the IO. + * + * This has to be called exactly once before pgaio_io_prep_*() is called. + */ +void +pgaio_io_set_target(PgAioHandle *ioh, PgAioTargetID targetid) +{ + Assert(ioh->state == PGAIO_HS_HANDED_OUT); + Assert(ioh->target == PGAIO_TID_INVALID); + + ioh->target = targetid; +} + +PgAioTargetData * +pgaio_io_get_target_data(PgAioHandle *ioh) +{ + return &ioh->target_data; +} + +/* + * Return a stringified description of the IO's target. + * + * The string is localized and allocated in the current memory context. + */ +char * +pgaio_io_get_target_description(PgAioHandle *ioh) +{ + return pgaio_target_info[ioh->target]->describe_identity(&ioh->target_data); +} + +/* + * Internal: Check if pgaio_io_reopen() is available for the IO. + */ +bool +pgaio_io_can_reopen(PgAioHandle *ioh) +{ + return pgaio_target_info[ioh->target]->reopen != NULL; +} + +/* + * Internal: Before executing an IO outside of the context of the process the + * IO has been prepared in, the file descriptor has to be reopened - any FD + * referenced in the IO itself, won't be valid in the separate process. + */ +void +pgaio_io_reopen(PgAioHandle *ioh) +{ + Assert(ioh->target >= 0 && ioh->target < PGAIO_TID_COUNT); + Assert(ioh->op >= 0 && ioh->op < PGAIO_OP_COUNT); + + pgaio_target_info[ioh->target]->reopen(ioh); +} diff --git a/src/backend/storage/aio/meson.build b/src/backend/storage/aio/meson.build index c822fd4ddf7..2c26089d52e 100644 --- a/src/backend/storage/aio/meson.build +++ b/src/backend/storage/aio/meson.build @@ -2,6 +2,10 @@ backend_sources += files( 'aio.c', + 'aio_callback.c', 'aio_init.c', + 'aio_io.c', + 'aio_target.c', + 'method_sync.c', 'read_stream.c', ) diff --git a/src/backend/storage/aio/method_sync.c b/src/backend/storage/aio/method_sync.c new file mode 100644 index 00000000000..43f9c8bd0b3 --- /dev/null +++ b/src/backend/storage/aio/method_sync.c @@ -0,0 +1,47 @@ +/*------------------------------------------------------------------------- + * + * method_sync.c + * AIO - perform "AIO" by executing it synchronously + * + * This method is mainly to check if AIO use causes regressions. Other IO + * methods might also fall back to the synchronous method for functionality + * they cannot provide. + * + * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * IDENTIFICATION + * src/backend/storage/aio/method_sync.c + * + *------------------------------------------------------------------------- + */ + +#include "postgres.h" + +#include "storage/aio.h" +#include "storage/aio_internal.h" + +static bool pgaio_sync_needs_synchronous_execution(PgAioHandle *ioh); +static int pgaio_sync_submit(uint16 num_staged_ios, PgAioHandle **staged_ios); + + +const IoMethodOps pgaio_sync_ops = { + .needs_synchronous_execution = pgaio_sync_needs_synchronous_execution, + .submit = pgaio_sync_submit, +}; + + + +static bool +pgaio_sync_needs_synchronous_execution(PgAioHandle *ioh) +{ + return true; +} + +static int +pgaio_sync_submit(uint16 num_staged_ios, PgAioHandle **staged_ios) +{ + elog(ERROR, "should be unreachable"); + + return 0; +} diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt index e199f071628..b5d3dcbf1e9 100644 --- a/src/backend/utils/activity/wait_event_names.txt +++ b/src/backend/utils/activity/wait_event_names.txt @@ -191,6 +191,9 @@ ABI_compatibility: Section: ClassName - WaitEventIO +AIO_SUBMIT "Waiting for AIO submission." +AIO_DRAIN "Waiting for IOs to finish." +AIO_COMPLETION "Waiting for completion callback." BASEBACKUP_READ "Waiting for base backup to read from a file." BASEBACKUP_SYNC "Waiting for data written by a base backup to reach durable storage." BASEBACKUP_WRITE "Waiting for base backup to write to a file." diff --git a/src/backend/utils/resowner/resowner.c b/src/backend/utils/resowner/resowner.c index ac5ca4a765e..e5d852b5ee6 100644 --- a/src/backend/utils/resowner/resowner.c +++ b/src/backend/utils/resowner/resowner.c @@ -47,6 +47,8 @@ #include "common/hashfn.h" #include "common/int.h" +#include "lib/ilist.h" +#include "storage/aio.h" #include "storage/ipc.h" #include "storage/predicate.h" #include "storage/proc.h" @@ -155,6 +157,12 @@ struct ResourceOwnerData /* The local locks cache. */ LOCALLOCK *locks[MAX_RESOWNER_LOCKS]; /* list of owned locks */ + + /* + * AIO handles need be registered in critical sections and therefore + * cannot use the normal ResoureElem mechanism. + */ + dlist_head aio_handles; }; @@ -425,6 +433,8 @@ ResourceOwnerCreate(ResourceOwner parent, const char *name) parent->firstchild = owner; } + dlist_init(&owner->aio_handles); + return owner; } @@ -725,6 +735,14 @@ ResourceOwnerReleaseInternal(ResourceOwner owner, * so issue warnings. In the abort case, just clean up quietly. */ ResourceOwnerReleaseAll(owner, phase, isCommit); + + /* XXX: Could probably be a later phase? */ + while (!dlist_is_empty(&owner->aio_handles)) + { + dlist_node *node = dlist_head_node(&owner->aio_handles); + + pgaio_io_release_resowner(node, !isCommit); + } } else if (phase == RESOURCE_RELEASE_LOCKS) { @@ -1082,3 +1100,15 @@ ResourceOwnerForgetLock(ResourceOwner owner, LOCALLOCK *locallock) elog(ERROR, "lock reference %p is not owned by resource owner %s", locallock, owner->name); } + +void +ResourceOwnerRememberAioHandle(ResourceOwner owner, struct dlist_node *ioh_node) +{ + dlist_push_tail(&owner->aio_handles, ioh_node); +} + +void +ResourceOwnerForgetAioHandle(ResourceOwner owner, struct dlist_node *ioh_node) +{ + dlist_delete_from(&owner->aio_handles, ioh_node); +} diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 3bec090428d..c7f34559b1b 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -1267,6 +1267,7 @@ InvalMessageArray InvalidationInfo InvalidationMsgsGroup IoMethod +IoMethodOps IpcMemoryId IpcMemoryKey IpcMemoryState @@ -2105,6 +2106,26 @@ Permutation PermutationStep PermutationStepBlocker PermutationStepBlockerType +PgAioBackend +PgAioCtl +PgAioHandle +PgAioHandleCallbackID +PgAioHandleCallbackStage +PgAioHandleCallbackComplete +PgAioHandleCallbackReport +PgAioHandleCallbacks +PgAioHandleCallbacksEntry +PgAioHandleFlags +PgAioHandleState +PgAioOp +PgAioOpData +PgAioResult +PgAioResultStatus +PgAioReturn +PgAioTargetData +PgAioTargetID +PgAioTargetInfo +PgAioWaitRef PgArchData PgBackendGSSStatus PgBackendSSLStatus -- 2.48.1.76.g4e746b1a31.dirty