HAMMER 53G/Many: Performance tuning.

[dragonfly.git] / sys / vfs / hammer / hammer_flusher.c

/*
 * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
 * 
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * $DragonFly: src/sys/vfs/hammer/hammer_flusher.c,v 1.23 2008/06/10 08:51:01 dillon Exp $
 */
/*
 * HAMMER dependancy flusher thread
 *
 * Meta data updates create buffer dependancies which are arranged as a
 * hierarchy of lists.
 */

#include "hammer.h"

static void hammer_flusher_master_thread(void *arg);
static void hammer_flusher_slave_thread(void *arg);
static void hammer_flusher_clean_loose_ios(hammer_mount_t hmp);
static void hammer_flusher_flush(hammer_mount_t hmp);
static void hammer_flusher_flush_inode(hammer_inode_t ip,
                                        hammer_transaction_t trans);
static int hammer_must_finalize_undo(hammer_mount_t hmp);
static void hammer_flusher_finalize(hammer_transaction_t trans, int final);

#define HAMMER_FLUSHER_IMMEDIATE        16

void
hammer_flusher_sync(hammer_mount_t hmp)
{
        int seq;

        if (hmp->flusher.td) {
                seq = hmp->flusher.next;
                if (hmp->flusher.signal++ == 0)
                        wakeup(&hmp->flusher.signal);
                while ((int)(seq - hmp->flusher.done) > 0)
                        tsleep(&hmp->flusher.done, 0, "hmrfls", 0);
        }
}

void
hammer_flusher_async(hammer_mount_t hmp)
{
        if (hmp->flusher.td) {
                if (hmp->flusher.signal++ == 0)
                        wakeup(&hmp->flusher.signal);
        }
}

void
hammer_flusher_create(hammer_mount_t hmp)
{
        hammer_flusher_info_t info;
        int i;

        hmp->flusher.signal = 0;
        hmp->flusher.act = 0;
        hmp->flusher.done = 0;
        hmp->flusher.next = 1;
        hmp->flusher.count = 0;
        hammer_ref(&hmp->flusher.finalize_lock);

        lwkt_create(hammer_flusher_master_thread, hmp,
                    &hmp->flusher.td, NULL, 0, -1, "hammer-M");
        for (i = 0; i < HAMMER_MAX_FLUSHERS; ++i) {
                info = kmalloc(sizeof(*info), M_HAMMER, M_WAITOK|M_ZERO);
                info->hmp = hmp;
                TAILQ_INIT(&info->work_list);
                ++hmp->flusher.count;
                hmp->flusher.info[i] = info;
                lwkt_create(hammer_flusher_slave_thread, info,
                            &info->td, NULL, 0, -1, "hammer-S%d", i);
        }
}

void
hammer_flusher_destroy(hammer_mount_t hmp)
{
        hammer_flusher_info_t info;
        int i;

        /*
         * Kill the master
         */
        hmp->flusher.exiting = 1;
        while (hmp->flusher.td) {
                ++hmp->flusher.signal;
                wakeup(&hmp->flusher.signal);
                tsleep(&hmp->flusher.exiting, 0, "hmrwex", hz);
        }

        /*
         * Kill the slaves
         */
        for (i = 0; i < HAMMER_MAX_FLUSHERS; ++i) {
                if ((info = hmp->flusher.info[i]) != NULL) {
                        KKASSERT(info->running == 0);
                        info->running = -1;
                        wakeup(&info->running);
                        while (info->td) {
                                tsleep(&info->td, 0, "hmrwwc", 0);
                        }
                        hmp->flusher.info[i] = NULL;
                        kfree(info, M_HAMMER);
                        --hmp->flusher.count;
                }
        }
        KKASSERT(hmp->flusher.count == 0);
}

static void
hammer_flusher_master_thread(void *arg)
{
        hammer_mount_t hmp = arg;

        for (;;) {
                while (hmp->flusher.group_lock)
                        tsleep(&hmp->flusher.group_lock, 0, "hmrhld", 0);
                kprintf("S");
                hmp->flusher.act = hmp->flusher.next;
                ++hmp->flusher.next;
                hammer_flusher_clean_loose_ios(hmp);
                hammer_flusher_flush(hmp);
                hammer_flusher_clean_loose_ios(hmp);
                hmp->flusher.done = hmp->flusher.act;
                wakeup(&hmp->flusher.done);

                /*
                 * Wait for activity.
                 */
                if (hmp->flusher.exiting && TAILQ_EMPTY(&hmp->flush_list))
                        break;

                /*
                 * This is a hack until we can dispose of frontend buffer
                 * cache buffers on the frontend.
                 */
                while (hmp->flusher.signal == 0)
                        tsleep(&hmp->flusher.signal, 0, "hmrwwa", 0);
                hmp->flusher.signal = 0;
        }

        /*
         * And we are done.
         */
        hmp->flusher.td = NULL;
        wakeup(&hmp->flusher.exiting);
        lwkt_exit();
}

static void
hammer_flusher_slave_thread(void *arg)
{
        hammer_flusher_info_t info;
        hammer_mount_t hmp;
        hammer_inode_t ip;

        info = arg;
        hmp = info->hmp;

        for (;;) {
                while (info->running == 0)
                        tsleep(&info->running, 0, "hmrssw", 0);
                if (info->running < 0)
                        break;
                while ((ip = TAILQ_FIRST(&info->work_list)) != NULL) {
                        TAILQ_REMOVE(&info->work_list, ip, flush_entry);
                        hammer_flusher_flush_inode(ip, &hmp->flusher.trans);
                }
                info->running = 0;
                if (--hmp->flusher.running == 0)
                        wakeup(&hmp->flusher.running);
        }
        info->td = NULL;
        wakeup(&info->td);
        lwkt_exit();
}

static void
hammer_flusher_clean_loose_ios(hammer_mount_t hmp)
{
        hammer_buffer_t buffer;
        hammer_io_t io;

        /*
         * loose ends - buffers without bp's aren't tracked by the kernel
         * and can build up, so clean them out.  This can occur when an
         * IO completes on a buffer with no references left.
         */
        while ((io = TAILQ_FIRST(&hmp->lose_list)) != NULL) {
                KKASSERT(io->mod_list == &hmp->lose_list);
                TAILQ_REMOVE(io->mod_list, io, mod_entry);
                io->mod_list = NULL;
                hammer_ref(&io->lock);
                buffer = (void *)io;
                hammer_rel_buffer(buffer, 0);
        }
}

/*
 * Flush all inodes in the current flush group.
 */
static void
hammer_flusher_flush(hammer_mount_t hmp)
{
        hammer_flusher_info_t info;
        hammer_inode_t ip;
        hammer_reserve_t resv;
        int i;

        /*
         * Flush the inodes
         */
        hammer_start_transaction_fls(&hmp->flusher.trans, hmp);
        i = 0;
        while ((ip = TAILQ_FIRST(&hmp->flush_list)) != NULL) {
                if (ip->flush_group != hmp->flusher.act)
                        break;
                TAILQ_REMOVE(&hmp->flush_list, ip, flush_entry);
                info = hmp->flusher.info[i];
                TAILQ_INSERT_TAIL(&info->work_list, ip, flush_entry);
                if (info->running == 0) {
                        ++hmp->flusher.running;
                        info->running = 1;
                        wakeup(&info->running);
                }
                /*hammer_flusher_flush_inode(ip, &trans);*/
                ++i;
                if (i == HAMMER_MAX_FLUSHERS || hmp->flusher.info[i] == NULL)
                        i = 0;
        }
        while (hmp->flusher.running)
                tsleep(&hmp->flusher.running, 0, "hmrfcc", 0);

        hammer_flusher_finalize(&hmp->flusher.trans, 1);
        hmp->flusher.tid = hmp->flusher.trans.tid;

        /*
         * Clean up any freed big-blocks (typically zone-2). 
         * resv->flush_group is typically set several flush groups ahead
         * of the free to ensure that the freed block is not reused until
         * it can no longer be reused.
         */
        while ((resv = TAILQ_FIRST(&hmp->delay_list)) != NULL) {
                if (resv->flush_group != hmp->flusher.act)
                        break;
                TAILQ_REMOVE(&hmp->delay_list, resv, delay_entry);
                hammer_blockmap_reserve_complete(hmp, resv);
        }
        hammer_done_transaction(&hmp->flusher.trans);
}

/*
 * Flush a single inode that is part of a flush group.
 */
static
void
hammer_flusher_flush_inode(hammer_inode_t ip, hammer_transaction_t trans)
{
        hammer_mount_t hmp = ip->hmp;

        hammer_lock_sh(&hmp->flusher.finalize_lock);
        ip->error = hammer_sync_inode(ip);
        hammer_flush_inode_done(ip);
        hammer_unlock(&hmp->flusher.finalize_lock);
        while (hmp->flusher.finalize_want)
                tsleep(&hmp->flusher.finalize_want, 0, "hmrsxx", 0);
        if (hammer_must_finalize_undo(hmp)) {
                hmp->flusher.finalize_want = 1;
                hammer_lock_ex(&hmp->flusher.finalize_lock);
                kprintf("HAMMER: Warning: UNDO area too small!");
                hammer_flusher_finalize(trans, 1);
                hammer_unlock(&hmp->flusher.finalize_lock);
                hmp->flusher.finalize_want = 0;
                wakeup(&hmp->flusher.finalize_want);
        } else if (trans->hmp->locked_dirty_count +
                   trans->hmp->io_running_count > hammer_limit_dirtybufs) {
                hmp->flusher.finalize_want = 1;
                hammer_lock_ex(&hmp->flusher.finalize_lock);
                kprintf("t");
                hammer_flusher_finalize(trans, 0);
                hammer_unlock(&hmp->flusher.finalize_lock);
                hmp->flusher.finalize_want = 0;
                wakeup(&hmp->flusher.finalize_want);
        }
}

/*
 * If the UNDO area gets over half full we have to flush it.  We can't
 * afford the UNDO area becoming completely full as that would break
 * the crash recovery atomicy.
 */
static
int
hammer_must_finalize_undo(hammer_mount_t hmp)
{
        if (hammer_undo_space(hmp) < hammer_undo_max(hmp) / 2) {
                hkprintf("*");
                return(1);
        } else {
                return(0);
        }
}

/*
 * Flush all pending UNDOs, wait for write completion, update the volume
 * header with the new UNDO end position, and flush it.  Then
 * asynchronously flush the meta-data.
 *
 * If this is the last finalization in a flush group we also synchronize
 * our cached blockmap and set hmp->flusher_undo_start and our cached undo
 * fifo first_offset so the next flush resets the FIFO pointers.
 */
static
void
hammer_flusher_finalize(hammer_transaction_t trans, int final)
{
        hammer_volume_t root_volume;
        hammer_blockmap_t cundomap, dundomap;
        hammer_mount_t hmp;
        hammer_io_t io;
        int count;
        int i;

        hmp = trans->hmp;
        root_volume = trans->rootvol;

        /*
         * Flush data buffers.  This can occur asynchronously and at any
         * time.  We must interlock against the frontend direct-data write
         * but do not have to acquire the sync-lock yet.
         */
        count = 0;
        while ((io = TAILQ_FIRST(&hmp->data_list)) != NULL) {
                hammer_ref(&io->lock);
                hammer_io_write_interlock(io);
                KKASSERT(io->type != HAMMER_STRUCTURE_VOLUME);
                hammer_io_flush(io);
                hammer_io_done_interlock(io);
                hammer_rel_buffer((hammer_buffer_t)io, 0);
                ++count;
        }

        /*
         * The sync-lock is required for the remaining sequence.  This lock
         * prevents meta-data from being modified.
         */
        hammer_sync_lock_ex(trans);

        /*
         * If we have been asked to finalize the volume header sync the
         * cached blockmap to the on-disk blockmap.  Generate an UNDO
         * record for the update.
         */
        if (final) {
                cundomap = &hmp->blockmap[0];
                dundomap = &root_volume->ondisk->vol0_blockmap[0];
                if (root_volume->io.modified) {
                        hammer_modify_volume(trans, root_volume,
                                             dundomap, sizeof(hmp->blockmap));
                        for (i = 0; i < HAMMER_MAX_ZONES; ++i)
                                hammer_crc_set_blockmap(&cundomap[i]);
                        bcopy(cundomap, dundomap, sizeof(hmp->blockmap));
                        hammer_modify_volume_done(root_volume);
                }
        }

        /*
         * Flush UNDOs
         */
        count = 0;
        while ((io = TAILQ_FIRST(&hmp->undo_list)) != NULL) {
                KKASSERT(io->modify_refs == 0);
                hammer_ref(&io->lock);
                KKASSERT(io->type != HAMMER_STRUCTURE_VOLUME);
                hammer_io_flush(io);
                hammer_rel_buffer((hammer_buffer_t)io, 0);
                ++count;
        }

        /*
         * Wait for I/Os to complete
         */
        crit_enter();
        while (hmp->io_running_count)
                tsleep(&hmp->io_running_count, 0, "hmrfl1", 0);
        crit_exit();

        /*
         * Update the on-disk volume header with new UNDO FIFO end position
         * (do not generate new UNDO records for this change).  We have to
         * do this for the UNDO FIFO whether (final) is set or not.
         *
         * Also update the on-disk next_tid field.  This does not require
         * an UNDO.  However, because our TID is generated before we get
         * the sync lock another sync may have beat us to the punch.
         *
         * The volume header will be flushed out synchronously.
         */
        dundomap = &root_volume->ondisk->vol0_blockmap[HAMMER_ZONE_UNDO_INDEX];
        cundomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];

        if (dundomap->first_offset != cundomap->first_offset ||
            dundomap->next_offset != cundomap->next_offset) {
                hammer_modify_volume(NULL, root_volume, NULL, 0);
                dundomap->first_offset = cundomap->first_offset;
                dundomap->next_offset = cundomap->next_offset;
                hammer_crc_set_blockmap(dundomap);
                hammer_crc_set_volume(root_volume->ondisk);
                if (root_volume->ondisk->vol0_next_tid < trans->tid)
                        root_volume->ondisk->vol0_next_tid = trans->tid;
                hammer_modify_volume_done(root_volume);
        }

        if (root_volume->io.modified) {
                hammer_io_flush(&root_volume->io);
        }

        /*
         * Wait for I/Os to complete
         */
        crit_enter();
        while (hmp->io_running_count)
                tsleep(&hmp->io_running_count, 0, "hmrfl2", 0);
        crit_exit();

        /*
         * Flush meta-data.  The meta-data will be undone if we crash
         * so we can safely flush it asynchronously.
         *
         * Repeated catchups will wind up flushing this update's meta-data
         * and the UNDO buffers for the next update simultaniously.  This
         * is ok.
         */
        count = 0;
        while ((io = TAILQ_FIRST(&hmp->meta_list)) != NULL) {
                KKASSERT(io->modify_refs == 0);
                hammer_ref(&io->lock);
                KKASSERT(io->type != HAMMER_STRUCTURE_VOLUME);
                hammer_io_flush(io);
                hammer_rel_buffer((hammer_buffer_t)io, 0);
                ++count;
        }

        /*
         * If this is the final finalization for the flush group set
         * up for the next sequence by setting a new first_offset in
         * our cached blockmap and
         * clearing the undo history.
         */
        if (final) {
                cundomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
                cundomap->first_offset = cundomap->next_offset;
                hammer_clear_undo_history(hmp);
        }

        hammer_sync_unlock(trans);
}