diff options
Diffstat (limited to 'fs/xfs/xfs_log_priv.h')
| -rw-r--r-- | fs/xfs/xfs_log_priv.h | 118 |
1 files changed, 114 insertions, 4 deletions
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h index 9cf695154451..8c072618965c 100644 --- a/fs/xfs/xfs_log_priv.h +++ b/fs/xfs/xfs_log_priv.h @@ -152,8 +152,6 @@ static inline uint xlog_get_client_id(__be32 i) #define XLOG_RECOVERY_NEEDED 0x4 /* log was recovered */ #define XLOG_IO_ERROR 0x8 /* log hit an I/O error, and being shutdown */ -typedef __uint32_t xlog_tid_t; - #ifdef __KERNEL__ /* @@ -379,6 +377,99 @@ typedef struct xlog_in_core { } xlog_in_core_t; /* + * The CIL context is used to aggregate per-transaction details as well be + * passed to the iclog for checkpoint post-commit processing. After being + * passed to the iclog, another context needs to be allocated for tracking the + * next set of transactions to be aggregated into a checkpoint. + */ +struct xfs_cil; + +struct xfs_cil_ctx { + struct xfs_cil *cil; + xfs_lsn_t sequence; /* chkpt sequence # */ + xfs_lsn_t start_lsn; /* first LSN of chkpt commit */ + xfs_lsn_t commit_lsn; /* chkpt commit record lsn */ + struct xlog_ticket *ticket; /* chkpt ticket */ + int nvecs; /* number of regions */ + int space_used; /* aggregate size of regions */ + struct list_head busy_extents; /* busy extents in chkpt */ + struct xfs_log_vec *lv_chain; /* logvecs being pushed */ + xfs_log_callback_t log_cb; /* completion callback hook. */ + struct list_head committing; /* ctx committing list */ +}; + +/* + * Committed Item List structure + * + * This structure is used to track log items that have been committed but not + * yet written into the log. It is used only when the delayed logging mount + * option is enabled. + * + * This structure tracks the list of committing checkpoint contexts so + * we can avoid the problem of having to hold out new transactions during a + * flush until we have a the commit record LSN of the checkpoint. We can + * traverse the list of committing contexts in xlog_cil_push_lsn() to find a + * sequence match and extract the commit LSN directly from there. If the + * checkpoint is still in the process of committing, we can block waiting for + * the commit LSN to be determined as well. This should make synchronous + * operations almost as efficient as the old logging methods. + */ +struct xfs_cil { + struct log *xc_log; + struct list_head xc_cil; + spinlock_t xc_cil_lock; + struct xfs_cil_ctx *xc_ctx; + struct rw_semaphore xc_ctx_lock; + struct list_head xc_committing; + sv_t xc_commit_wait; +}; + +/* + * The amount of log space we should the CIL to aggregate is difficult to size. + * Whatever we chose we have to make we can get a reservation for the log space + * effectively, that it is large enough to capture sufficient relogging to + * reduce log buffer IO significantly, but it is not too large for the log or + * induces too much latency when writing out through the iclogs. We track both + * space consumed and the number of vectors in the checkpoint context, so we + * need to decide which to use for limiting. + * + * Every log buffer we write out during a push needs a header reserved, which + * is at least one sector and more for v2 logs. Hence we need a reservation of + * at least 512 bytes per 32k of log space just for the LR headers. That means + * 16KB of reservation per megabyte of delayed logging space we will consume, + * plus various headers. The number of headers will vary based on the num of + * io vectors, so limiting on a specific number of vectors is going to result + * in transactions of varying size. IOWs, it is more consistent to track and + * limit space consumed in the log rather than by the number of objects being + * logged in order to prevent checkpoint ticket overruns. + * + * Further, use of static reservations through the log grant mechanism is + * problematic. It introduces a lot of complexity (e.g. reserve grant vs write + * grant) and a significant deadlock potential because regranting write space + * can block on log pushes. Hence if we have to regrant log space during a log + * push, we can deadlock. + * + * However, we can avoid this by use of a dynamic "reservation stealing" + * technique during transaction commit whereby unused reservation space in the + * transaction ticket is transferred to the CIL ctx commit ticket to cover the + * space needed by the checkpoint transaction. This means that we never need to + * specifically reserve space for the CIL checkpoint transaction, nor do we + * need to regrant space once the checkpoint completes. This also means the + * checkpoint transaction ticket is specific to the checkpoint context, rather + * than the CIL itself. + * + * With dynamic reservations, we can basically make up arbitrary limits for the + * checkpoint size so long as they don't violate any other size rules. Hence + * the initial maximum size for the checkpoint transaction will be set to a + * quarter of the log or 8MB, which ever is smaller. 8MB is an arbitrary limit + * right now based on the latency of writing out a large amount of data through + * the circular iclog buffers. + */ + +#define XLOG_CIL_SPACE_LIMIT(log) \ + (min((log->l_logsize >> 2), (8 * 1024 * 1024))) + +/* * The reservation head lsn is not made up of a cycle number and block number. * Instead, it uses a cycle number and byte number. Logs don't expect to * overflow 31 bits worth of byte offset, so using a byte number will mean @@ -388,6 +479,7 @@ typedef struct log { /* The following fields don't need locking */ struct xfs_mount *l_mp; /* mount point */ struct xfs_ail *l_ailp; /* AIL log is working with */ + struct xfs_cil *l_cilp; /* CIL log is working with */ struct xfs_buf *l_xbuf; /* extra buffer for log * wrapping */ struct xfs_buftarg *l_targ; /* buftarg of log */ @@ -438,14 +530,17 @@ typedef struct log { #define XLOG_FORCED_SHUTDOWN(log) ((log)->l_flags & XLOG_IO_ERROR) - /* common routines */ extern xfs_lsn_t xlog_assign_tail_lsn(struct xfs_mount *mp); extern int xlog_recover(xlog_t *log); extern int xlog_recover_finish(xlog_t *log); extern void xlog_pack_data(xlog_t *log, xlog_in_core_t *iclog, int); -extern kmem_zone_t *xfs_log_ticket_zone; +extern kmem_zone_t *xfs_log_ticket_zone; +struct xlog_ticket *xlog_ticket_alloc(struct log *log, int unit_bytes, + int count, char client, uint xflags, + int alloc_flags); + static inline void xlog_write_adv_cnt(void **ptr, int *len, int *off, size_t bytes) @@ -455,6 +550,21 @@ xlog_write_adv_cnt(void **ptr, int *len, int *off, size_t bytes) *off += bytes; } +void xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket); +int xlog_write(struct log *log, struct xfs_log_vec *log_vector, + struct xlog_ticket *tic, xfs_lsn_t *start_lsn, + xlog_in_core_t **commit_iclog, uint flags); + +/* + * Committed Item List interfaces + */ +int xlog_cil_init(struct log *log); +void xlog_cil_init_post_recovery(struct log *log); +void xlog_cil_destroy(struct log *log); + +int xlog_cil_push(struct log *log, int push_now); +xfs_lsn_t xlog_cil_push_lsn(struct log *log, xfs_lsn_t push_sequence); + /* * Unmount record type is used as a pseudo transaction type for the ticket. * It's value must be outside the range of XFS_TRANS_* values. |