// SPDX-License-Identifier: GPL-2.0 /* * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc. * All Rights Reserved. */ #ifndef __XFS_LOG_PRIV_H__ #define __XFS_LOG_PRIV_H__ #include "xfs_extent_busy.h" /* for struct xfs_busy_extents */ struct xfs_buf; struct xlog; struct xlog_ticket; struct xfs_mount; struct xfs_log_iovec { void *i_addr;/* beginning address of region */ int i_len; /* length in bytes of region */ uint i_type; /* type of region */ }; struct xfs_log_vec { struct list_head lv_list; /* CIL lv chain ptrs */ uint32_t lv_order_id; /* chain ordering info */ int lv_niovecs; /* number of iovecs in lv */ struct xfs_log_iovec *lv_iovecp; /* iovec array */ struct xfs_log_item *lv_item; /* owner */ char *lv_buf; /* formatted buffer */ int lv_bytes; /* accounted space in buffer */ int lv_buf_used; /* buffer space used so far */ int lv_alloc_size; /* size of allocated lv */ }; /* * get client id from packed copy. * * this hack is here because the xlog_pack code copies four bytes * of xlog_op_header containing the fields oh_clientid, oh_flags * and oh_res2 into the packed copy. * * later on this four byte chunk is treated as an int and the * client id is pulled out. * * this has endian issues, of course. */ static inline uint xlog_get_client_id(__be32 i) { return be32_to_cpu(i) >> 24; } /* * In core log state */ enum xlog_iclog_state { XLOG_STATE_ACTIVE, /* Current IC log being written to */ XLOG_STATE_WANT_SYNC, /* Want to sync this iclog; no more writes */ XLOG_STATE_SYNCING, /* This IC log is syncing */ XLOG_STATE_DONE_SYNC, /* Done syncing to disk */ XLOG_STATE_CALLBACK, /* Callback functions now */ XLOG_STATE_DIRTY, /* Dirty IC log, not ready for ACTIVE status */ }; #define XLOG_STATE_STRINGS \ { XLOG_STATE_ACTIVE, "XLOG_STATE_ACTIVE" }, \ { XLOG_STATE_WANT_SYNC, "XLOG_STATE_WANT_SYNC" }, \ { XLOG_STATE_SYNCING, "XLOG_STATE_SYNCING" }, \ { XLOG_STATE_DONE_SYNC, "XLOG_STATE_DONE_SYNC" }, \ { XLOG_STATE_CALLBACK, "XLOG_STATE_CALLBACK" }, \ { XLOG_STATE_DIRTY, "XLOG_STATE_DIRTY" } /* * In core log flags */ #define XLOG_ICL_NEED_FLUSH (1u << 0) /* iclog needs REQ_PREFLUSH */ #define XLOG_ICL_NEED_FUA (1u << 1) /* iclog needs REQ_FUA */ #define XLOG_ICL_STRINGS \ { XLOG_ICL_NEED_FLUSH, "XLOG_ICL_NEED_FLUSH" }, \ { XLOG_ICL_NEED_FUA, "XLOG_ICL_NEED_FUA" } /* * Log ticket flags */ #define XLOG_TIC_PERM_RESERV (1u << 0) /* permanent reservation */ #define XLOG_TIC_FLAGS \ { XLOG_TIC_PERM_RESERV, "XLOG_TIC_PERM_RESERV" } /* * Below are states for covering allocation transactions. * By covering, we mean changing the h_tail_lsn in the last on-disk * log write such that no allocation transactions will be re-done during * recovery after a system crash. Recovery starts at the last on-disk * log write. * * These states are used to insert dummy log entries to cover * space allocation transactions which can undo non-transactional changes * after a crash. Writes to a file with space * already allocated do not result in any transactions. Allocations * might include space beyond the EOF. So if we just push the EOF a * little, the last transaction for the file could contain the wrong * size. If there is no file system activity, after an allocation * transaction, and the system crashes, the allocation transaction * will get replayed and the file will be truncated. This could * be hours/days/... after the allocation occurred. * * The fix for this is to do two dummy transactions when the * system is idle. We need two dummy transaction because the h_tail_lsn * in the log record header needs to point beyond the last possible * non-dummy transaction. The first dummy changes the h_tail_lsn to * the first transaction before the dummy. The second dummy causes * h_tail_lsn to point to the first dummy. Recovery starts at h_tail_lsn. * * These dummy transactions get committed when everything * is idle (after there has been some activity). * * There are 5 states used to control this. * * IDLE -- no logging has been done on the file system or * we are done covering previous transactions. * NEED -- logging has occurred and we need a dummy transaction * when the log becomes idle. * DONE -- we were in the NEED state and have committed a dummy * transaction. * NEED2 -- we detected that a dummy transaction has gone to the * on disk log with no other transactions. * DONE2 -- we committed a dummy transaction when in the NEED2 state. * * There are two places where we switch states: * * 1.) In xfs_sync, when we detect an idle log and are in NEED or NEED2. * We commit the dummy transaction and switch to DONE or DONE2, * respectively. In all other states, we don't do anything. * * 2.) When we finish writing the on-disk log (xlog_state_clean_log). * * No matter what state we are in, if this isn't the dummy * transaction going out, the next state is NEED. * So, if we aren't in the DONE or DONE2 states, the next state * is NEED. We can't be finishing a write of the dummy record * unless it was committed and the state switched to DONE or DONE2. * * If we are in the DONE state and this was a write of the * dummy transaction, we move to NEED2. * * If we are in the DONE2 state and this was a write of the * dummy transaction, we move to IDLE. * * * Writing only one dummy transaction can get appended to * one file space allocation. When this happens, the log recovery * code replays the space allocation and a file could be truncated. * This is why we have the NEED2 and DONE2 states before going idle. */ #define XLOG_STATE_COVER_IDLE 0 #define XLOG_STATE_COVER_NEED 1 #define XLOG_STATE_COVER_DONE 2 #define XLOG_STATE_COVER_NEED2 3 #define XLOG_STATE_COVER_DONE2 4 #define XLOG_COVER_OPS 5 struct xlog_ticket { struct list_head t_queue; /* reserve/write queue */ struct task_struct *t_task; /* task that owns this ticket */ xlog_tid_t t_tid; /* transaction identifier */ atomic_t t_ref; /* ticket reference count */ int t_curr_res; /* current reservation */ int t_unit_res; /* unit reservation */ char t_ocnt; /* original unit count */ char t_cnt; /* current unit count */ uint8_t t_flags; /* properties of reservation */ int t_iclog_hdrs; /* iclog hdrs in t_curr_res */ }; /* * In-core log structure. * * - ic_forcewait is used to implement synchronous forcing of the iclog to disk. * - ic_next is the pointer to the next iclog in the ring. * - ic_log is a pointer back to the global log structure. * - ic_size is the full size of the log buffer, minus the cycle headers. * - ic_offset is the current number of bytes written to in this iclog. * - ic_refcnt is bumped when someone is writing to the log. * - ic_state is the state of the iclog. * * Because of cacheline contention on large machines, we need to separate * various resources onto different cachelines. To start with, make the * structure cacheline aligned. The following fields can be contended on * by independent processes: * * - ic_callbacks * - ic_refcnt * - fields protected by the global l_icloglock * * so we need to ensure that these fields are located in separate cachelines. * We'll put all the read-only and l_icloglock fields in the first cacheline, * and move everything else out to subsequent cachelines. */ struct xlog_in_core { wait_queue_head_t ic_force_wait; wait_queue_head_t ic_write_wait; struct xlog_in_core *ic_next; struct xlog_in_core *ic_prev; struct xlog *ic_log; u32 ic_size; u32 ic_offset; enum xlog_iclog_state ic_state; unsigned int ic_flags; void *ic_datap; /* pointer to iclog data */ struct list_head ic_callbacks; /* reference counts need their own cacheline */ atomic_t ic_refcnt ____cacheline_aligned_in_smp; struct xlog_rec_header *ic_header; #ifdef DEBUG bool ic_fail_crc : 1; #endif struct semaphore ic_sema; struct work_struct ic_end_io_work; struct bio ic_bio; struct bio_vec ic_bvec[]; }; /* * 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_csn_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_in_core *commit_iclog; struct xlog_ticket *ticket; /* chkpt ticket */ atomic_t space_used; /* aggregate size of regions */ struct xfs_busy_extents busy_extents; struct list_head log_items; /* log items in chkpt */ struct list_head lv_chain; /* logvecs being pushed */ struct list_head iclog_entry; struct list_head committing; /* ctx committing list */ struct work_struct push_work; atomic_t order_id; /* * CPUs that could have added items to the percpu CIL data. Access is * coordinated with xc_ctx_lock. */ struct cpumask cil_pcpmask; }; /* * Per-cpu CIL tracking items */ struct xlog_cil_pcp { int32_t space_used; uint32_t space_reserved; struct list_head busy_extents; struct list_head log_items; }; /* * 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 xlog *xc_log; unsigned long xc_flags; atomic_t xc_iclog_hdrs; struct workqueue_struct *xc_push_wq; struct rw_semaphore xc_ctx_lock ____cacheline_aligned_in_smp; struct xfs_cil_ctx *xc_ctx; spinlock_t xc_push_lock ____cacheline_aligned_in_smp; xfs_csn_t xc_push_seq; bool xc_push_commit_stable; struct list_head xc_committing; wait_queue_head_t xc_commit_wait; wait_queue_head_t xc_start_wait; xfs_csn_t xc_current_sequence; wait_queue_head_t xc_push_wait; /* background push throttle */ void __percpu *xc_pcp; /* percpu CIL structures */ } ____cacheline_aligned_in_smp; /* xc_flags bit values */ #define XLOG_CIL_EMPTY 1 #define XLOG_CIL_PCP_SPACE 2 /* * The amount of log space we allow the CIL to aggregate is difficult to size. * Whatever we choose, we have to make sure 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 effectively make up arbitrary limits for * the checkpoint size so long as they don't violate any other size rules. * Recovery imposes a rule that no transaction exceed half the log, so we are * limited by that. Furthermore, the log transaction reservation subsystem * tries to keep 25% of the log free, so we need to keep below that limit or we * risk running out of free log space to start any new transactions. * * In order to keep background CIL push efficient, we only need to ensure the * CIL is large enough to maintain sufficient in-memory relogging to avoid * repeated physical writes of frequently modified metadata. If we allow the CIL * to grow to a substantial fraction of the log, then we may be pinning hundreds * of megabytes of metadata in memory until the CIL flushes. This can cause * issues when we are running low on memory - pinned memory cannot be reclaimed, * and the CIL consumes a lot of memory. Hence we need to set an upper physical * size limit for the CIL that limits the maximum amount of memory pinned by the * CIL but does not limit performance by reducing relogging efficiency * significantly. * * As such, the CIL push threshold ends up being the smaller of two thresholds: * - a threshold large enough that it allows CIL to be pushed and progress to be * made without excessive blocking of incoming transaction commits. This is * defined to be 12.5% of the log space - half the 25% push threshold of the * AIL. * - small enough that it doesn't pin excessive amounts of memory but maintains * close to peak relogging efficiency. This is defined to be 16x the iclog * buffer window (32MB) as measurements have shown this to be roughly the * point of diminishing performance increases under highly concurrent * modification workloads. * * To prevent the CIL from overflowing upper commit size bounds, we introduce a * new threshold at which we block committing transactions until the background * CIL commit commences and switches to a new context. While this is not a hard * limit, it forces the process committing a transaction to the CIL to block and * yeild the CPU, giving the CIL push work a chance to be scheduled and start * work. This prevents a process running lots of transactions from overfilling * the CIL because it is not yielding the CPU. We set the blocking limit at * twice the background push space threshold so we keep in line with the AIL * push thresholds. * * Note: this is not a -hard- limit as blocking is applied after the transaction * is inserted into the CIL and the push has been triggered. It is largely a * throttling mechanism that allows the CIL push to be scheduled and run. A hard * limit will be difficult to implement without introducing global serialisation * in the CIL commit fast path, and it's not at all clear that we actually need * such hard limits given the ~7 years we've run without a hard limit before * finding the first situation where a checkpoint size overflow actually * occurred. Hence the simple throttle, and an ASSERT check to tell us that * we've overrun the max size. */ #define XLOG_CIL_SPACE_LIMIT(log) \ min_t(int, (log)->l_logsize >> 3, BBTOB(XLOG_TOTAL_REC_SHIFT(log)) << 4) #define XLOG_CIL_BLOCKING_SPACE_LIMIT(log) \ (XLOG_CIL_SPACE_LIMIT(log) * 2) /* * ticket grant locks, queues and accounting have their own cachlines * as these are quite hot and can be operated on concurrently. */ struct xlog_grant_head { spinlock_t lock ____cacheline_aligned_in_smp; struct list_head waiters; atomic64_t grant; }; /* * 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 * that round off problems won't occur when releasing partial reservations. */ struct xlog { /* 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_buftarg *l_targ; /* buftarg of log */ struct workqueue_struct *l_ioend_workqueue; /* for I/O completions */ struct delayed_work l_work; /* background flush work */ long l_opstate; /* operational state */ uint l_quotaoffs_flag; /* XFS_DQ_*, for QUOTAOFFs */ struct list_head *l_buf_cancel_table; struct list_head r_dfops; /* recovered log intent items */ int l_iclog_hsize; /* size of iclog header */ uint l_sectBBsize; /* sector size in BBs (2^n) */ int l_iclog_size; /* size of log in bytes */ int l_iclog_bufs; /* number of iclog buffers */ xfs_daddr_t l_logBBstart; /* start block of log */ int l_logsize; /* size of log in bytes */ int l_logBBsize; /* size of log in BB chunks */ /* The following block of fields are changed while holding icloglock */ wait_queue_head_t l_flush_wait ____cacheline_aligned_in_smp; /* waiting for iclog flush */ int l_covered_state;/* state of "covering disk * log entries" */ struct xlog_in_core *l_iclog; /* head log queue */ spinlock_t l_icloglock; /* grab to change iclog state */ int l_curr_cycle; /* Cycle number of log writes */ int l_prev_cycle; /* Cycle number before last * block increment */ int l_curr_block; /* current logical log block */ int l_prev_block; /* previous logical log block */ /* * l_tail_lsn is atomic so it can be set and read without needing to * hold specific locks. To avoid operations contending with other hot * objects, it on a separate cacheline. */ /* lsn of 1st LR with unflushed * buffers */ atomic64_t l_tail_lsn ____cacheline_aligned_in_smp; struct xlog_grant_head l_reserve_head; struct xlog_grant_head l_write_head; uint64_t l_tail_space; struct xfs_kobj l_kobj; /* log recovery lsn tracking (for buffer submission */ xfs_lsn_t l_recovery_lsn; uint32_t l_iclog_roundoff;/* padding roundoff */ }; /* * Bits for operational state */ #define XLOG_ACTIVE_RECOVERY 0 /* in the middle of recovery */ #define XLOG_RECOVERY_NEEDED 1 /* log was recovered */ #define XLOG_IO_ERROR 2 /* log hit an I/O error, and being shutdown */ #define XLOG_TAIL_WARN 3 /* log tail verify warning issued */ #define XLOG_SHUTDOWN_STARTED 4 /* xlog_force_shutdown() exclusion */ static inline bool xlog_recovery_needed(struct xlog *log) { return test_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate); } static inline bool xlog_in_recovery(struct xlog *log) { return test_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate); } static inline bool xlog_is_shutdown(struct xlog *log) { return test_bit(XLOG_IO_ERROR, &log->l_opstate); } /* * Wait until the xlog_force_shutdown() has marked the log as shut down * so xlog_is_shutdown() will always return true. */ static inline void xlog_shutdown_wait( struct xlog *log) { wait_var_event(&log->l_opstate, xlog_is_shutdown(log)); } /* common routines */ extern int xlog_recover( struct xlog *log); extern int xlog_recover_finish( struct xlog *log); extern void xlog_recover_cancel(struct xlog *); __le32 xlog_cksum(struct xlog *log, struct xlog_rec_header *rhead, char *dp, unsigned int hdrsize, unsigned int size); extern struct kmem_cache *xfs_log_ticket_cache; struct xlog_ticket *xlog_ticket_alloc(struct xlog *log, int unit_bytes, int count, bool permanent); void xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket); void xlog_print_trans(struct xfs_trans *); int xlog_write(struct xlog *log, struct xfs_cil_ctx *ctx, struct list_head *lv_chain, struct xlog_ticket *tic, uint32_t len); int xlog_write_one_vec(struct xlog *log, struct xfs_cil_ctx *ctx, struct xfs_log_iovec *reg, struct xlog_ticket *ticket); void xfs_log_ticket_ungrant(struct xlog *log, struct xlog_ticket *ticket); void xfs_log_ticket_regrant(struct xlog *log, struct xlog_ticket *ticket); void xlog_state_switch_iclogs(struct xlog *log, struct xlog_in_core *iclog, int eventual_size); int xlog_state_release_iclog(struct xlog *log, struct xlog_in_core *iclog, struct xlog_ticket *ticket); /* * When we crack an atomic LSN, we sample it first so that the value will not * change while we are cracking it into the component values. This means we * will always get consistent component values to work from. This should always * be used to sample and crack LSNs that are stored and updated in atomic * variables. */ static inline void xlog_crack_atomic_lsn(atomic64_t *lsn, uint *cycle, uint *block) { xfs_lsn_t val = atomic64_read(lsn); *cycle = CYCLE_LSN(val); *block = BLOCK_LSN(val); } /* * Calculate and assign a value to an atomic LSN variable from component pieces. */ static inline void xlog_assign_atomic_lsn(atomic64_t *lsn, uint cycle, uint block) { atomic64_set(lsn, xlog_assign_lsn(cycle, block)); } /* * Committed Item List interfaces */ int xlog_cil_init(struct xlog *log); void xlog_cil_init_post_recovery(struct xlog *log); void xlog_cil_destroy(struct xlog *log); bool xlog_cil_empty(struct xlog *log); void xlog_cil_commit(struct xlog *log, struct xfs_trans *tp, xfs_csn_t *commit_seq, bool regrant); void xlog_cil_set_ctx_write_state(struct xfs_cil_ctx *ctx, struct xlog_in_core *iclog); /* * CIL force routines */ void xlog_cil_flush(struct xlog *log); xfs_lsn_t xlog_cil_force_seq(struct xlog *log, xfs_csn_t sequence); static inline void xlog_cil_force(struct xlog *log) { xlog_cil_force_seq(log, log->l_cilp->xc_current_sequence); } /* * Wrapper function for waiting on a wait queue serialised against wakeups * by a spinlock. This matches the semantics of all the wait queues used in the * log code. */ static inline void xlog_wait( struct wait_queue_head *wq, struct spinlock *lock) __releases(lock) { DECLARE_WAITQUEUE(wait, current); add_wait_queue_exclusive(wq, &wait); __set_current_state(TASK_UNINTERRUPTIBLE); spin_unlock(lock); schedule(); remove_wait_queue(wq, &wait); } int xlog_wait_on_iclog(struct xlog_in_core *iclog) __releases(iclog->ic_log->l_icloglock); /* Calculate the distance between two LSNs in bytes */ static inline uint64_t xlog_lsn_sub( struct xlog *log, xfs_lsn_t high, xfs_lsn_t low) { uint32_t hi_cycle = CYCLE_LSN(high); uint32_t hi_block = BLOCK_LSN(high); uint32_t lo_cycle = CYCLE_LSN(low); uint32_t lo_block = BLOCK_LSN(low); if (hi_cycle == lo_cycle) return BBTOB(hi_block - lo_block); ASSERT((hi_cycle == lo_cycle + 1) || xlog_is_shutdown(log)); return (uint64_t)log->l_logsize - BBTOB(lo_block - hi_block); } void xlog_grant_return_space(struct xlog *log, xfs_lsn_t old_head, xfs_lsn_t new_head); /* * The LSN is valid so long as it is behind the current LSN. If it isn't, this * means that the next log record that includes this metadata could have a * smaller LSN. In turn, this means that the modification in the log would not * replay. */ static inline bool xlog_valid_lsn( struct xlog *log, xfs_lsn_t lsn) { int cur_cycle; int cur_block; bool valid = true; /* * First, sample the current lsn without locking to avoid added * contention from metadata I/O. The current cycle and block are updated * (in xlog_state_switch_iclogs()) and read here in a particular order * to avoid false negatives (e.g., thinking the metadata LSN is valid * when it is not). * * The current block is always rewound before the cycle is bumped in * xlog_state_switch_iclogs() to ensure the current LSN is never seen in * a transiently forward state. Instead, we can see the LSN in a * transiently behind state if we happen to race with a cycle wrap. */ cur_cycle = READ_ONCE(log->l_curr_cycle); smp_rmb(); cur_block = READ_ONCE(log->l_curr_block); if ((CYCLE_LSN(lsn) > cur_cycle) || (CYCLE_LSN(lsn) == cur_cycle && BLOCK_LSN(lsn) > cur_block)) { /* * If the metadata LSN appears invalid, it's possible the check * above raced with a wrap to the next log cycle. Grab the lock * to check for sure. */ spin_lock(&log->l_icloglock); cur_cycle = log->l_curr_cycle; cur_block = log->l_curr_block; spin_unlock(&log->l_icloglock); if ((CYCLE_LSN(lsn) > cur_cycle) || (CYCLE_LSN(lsn) == cur_cycle && BLOCK_LSN(lsn) > cur_block)) valid = false; } return valid; } /* * Log vector and shadow buffers can be large, so we need to use kvmalloc() here * to ensure success. Unfortunately, kvmalloc() only allows GFP_KERNEL contexts * to fall back to vmalloc, so we can't actually do anything useful with gfp * flags to control the kmalloc() behaviour within kvmalloc(). Hence kmalloc() * will do direct reclaim and compaction in the slow path, both of which are * horrendously expensive. We just want kmalloc to fail fast and fall back to * vmalloc if it can't get something straight away from the free lists or * buddy allocator. Hence we have to open code kvmalloc outselves here. * * This assumes that the caller uses memalloc_nofs_save task context here, so * despite the use of GFP_KERNEL here, we are going to be doing GFP_NOFS * allocations. This is actually the only way to make vmalloc() do GFP_NOFS * allocations, so lets just all pretend this is a GFP_KERNEL context * operation.... */ static inline void * xlog_kvmalloc( size_t buf_size) { gfp_t flags = GFP_KERNEL; void *p; flags &= ~__GFP_DIRECT_RECLAIM; flags |= __GFP_NOWARN | __GFP_NORETRY; do { p = kmalloc(buf_size, flags); if (!p) p = vmalloc(buf_size); } while (!p); return p; } /* * Given a count of iovecs and space for a log item, compute the space we need * in the log to store that data plus the log headers. */ static inline unsigned int xlog_item_space( unsigned int niovecs, unsigned int nbytes) { nbytes += niovecs * (sizeof(uint64_t) + sizeof(struct xlog_op_header)); return round_up(nbytes, sizeof(uint64_t)); } /* * Cycles over XLOG_CYCLE_DATA_SIZE overflow into the extended header that was * added for v2 logs. Addressing for the cycles array there is off by one, * because the first batch of cycles is in the original header. */ static inline __be32 *xlog_cycle_data(struct xlog_rec_header *rhead, unsigned i) { if (i >= XLOG_CYCLE_DATA_SIZE) { unsigned j = i / XLOG_CYCLE_DATA_SIZE; unsigned k = i % XLOG_CYCLE_DATA_SIZE; return &rhead->h_ext[j - 1].xh_cycle_data[k]; } return &rhead->h_cycle_data[i]; } #endif /* __XFS_LOG_PRIV_H__ */
