rrpc: Round-robin sector target with cost-based gc

This target allows an Open-Channel SSD to be exposed asas a block
device.

It implements a round-robin approach for sector allocation,
together with a greedy cost-based garbage collector.

Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Matias Bjørling 2015-10-28 19:54:57 +01:00 committed by Jens Axboe
parent 48add0f5a6
commit ae1519ec44
4 changed files with 1571 additions and 0 deletions

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@ -32,4 +32,11 @@ config NVM_GENNVM
functionality to device, while keeping data placement and garbage
collection decisions on the host.
config NVM_RRPC
tristate "Round-robin Hybrid Open-Channel SSD target"
---help---
Allows an open-channel SSD to be exposed as a block device to the
host. The target is implemented using a linear mapping table and
cost-based garbage collection. It is optimized for 4K IO sizes.
endif # NVM

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@ -4,3 +4,4 @@
obj-$(CONFIG_NVM) := core.o
obj-$(CONFIG_NVM_GENNVM) += gennvm.o
obj-$(CONFIG_NVM_RRPC) += rrpc.o

1324
drivers/lightnvm/rrpc.c Normal file

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239
drivers/lightnvm/rrpc.h Normal file
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@ -0,0 +1,239 @@
/*
* Copyright (C) 2015 IT University of Copenhagen
* Initial release: Matias Bjorling <m@bjorling.me>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* Implementation of a Round-robin page-based Hybrid FTL for Open-channel SSDs.
*/
#ifndef RRPC_H_
#define RRPC_H_
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/bio.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/vmalloc.h>
#include <linux/lightnvm.h>
/* Run only GC if less than 1/X blocks are free */
#define GC_LIMIT_INVERSE 10
#define GC_TIME_SECS 100
#define RRPC_SECTOR (512)
#define RRPC_EXPOSED_PAGE_SIZE (4096)
#define NR_PHY_IN_LOG (RRPC_EXPOSED_PAGE_SIZE / RRPC_SECTOR)
struct rrpc_inflight {
struct list_head reqs;
spinlock_t lock;
};
struct rrpc_inflight_rq {
struct list_head list;
sector_t l_start;
sector_t l_end;
};
struct rrpc_rq {
struct rrpc_inflight_rq inflight_rq;
struct rrpc_addr *addr;
unsigned long flags;
};
struct rrpc_block {
struct nvm_block *parent;
struct list_head prio;
#define MAX_INVALID_PAGES_STORAGE 8
/* Bitmap for invalid page intries */
unsigned long invalid_pages[MAX_INVALID_PAGES_STORAGE];
/* points to the next writable page within a block */
unsigned int next_page;
/* number of pages that are invalid, wrt host page size */
unsigned int nr_invalid_pages;
spinlock_t lock;
atomic_t data_cmnt_size; /* data pages committed to stable storage */
};
struct rrpc_lun {
struct rrpc *rrpc;
struct nvm_lun *parent;
struct rrpc_block *cur, *gc_cur;
struct rrpc_block *blocks; /* Reference to block allocation */
struct list_head prio_list; /* Blocks that may be GC'ed */
struct work_struct ws_gc;
spinlock_t lock;
};
struct rrpc {
/* instance must be kept in top to resolve rrpc in unprep */
struct nvm_tgt_instance instance;
struct nvm_dev *dev;
struct gendisk *disk;
sector_t poffset; /* physical page offset */
int lun_offset;
int nr_luns;
struct rrpc_lun *luns;
/* calculated values */
unsigned long long nr_pages;
unsigned long total_blocks;
/* Write strategy variables. Move these into each for structure for each
* strategy
*/
atomic_t next_lun; /* Whenever a page is written, this is updated
* to point to the next write lun
*/
spinlock_t bio_lock;
struct bio_list requeue_bios;
struct work_struct ws_requeue;
/* Simple translation map of logical addresses to physical addresses.
* The logical addresses is known by the host system, while the physical
* addresses are used when writing to the disk block device.
*/
struct rrpc_addr *trans_map;
/* also store a reverse map for garbage collection */
struct rrpc_rev_addr *rev_trans_map;
spinlock_t rev_lock;
struct rrpc_inflight inflights;
mempool_t *addr_pool;
mempool_t *page_pool;
mempool_t *gcb_pool;
mempool_t *rq_pool;
struct timer_list gc_timer;
struct workqueue_struct *krqd_wq;
struct workqueue_struct *kgc_wq;
};
struct rrpc_block_gc {
struct rrpc *rrpc;
struct rrpc_block *rblk;
struct work_struct ws_gc;
};
/* Logical to physical mapping */
struct rrpc_addr {
sector_t addr;
struct rrpc_block *rblk;
};
/* Physical to logical mapping */
struct rrpc_rev_addr {
sector_t addr;
};
static inline sector_t rrpc_get_laddr(struct bio *bio)
{
return bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
}
static inline unsigned int rrpc_get_pages(struct bio *bio)
{
return bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
}
static inline sector_t rrpc_get_sector(sector_t laddr)
{
return laddr * NR_PHY_IN_LOG;
}
static inline int request_intersects(struct rrpc_inflight_rq *r,
sector_t laddr_start, sector_t laddr_end)
{
return (laddr_end >= r->l_start && laddr_end <= r->l_end) &&
(laddr_start >= r->l_start && laddr_start <= r->l_end);
}
static int __rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
unsigned pages, struct rrpc_inflight_rq *r)
{
sector_t laddr_end = laddr + pages - 1;
struct rrpc_inflight_rq *rtmp;
spin_lock_irq(&rrpc->inflights.lock);
list_for_each_entry(rtmp, &rrpc->inflights.reqs, list) {
if (unlikely(request_intersects(rtmp, laddr, laddr_end))) {
/* existing, overlapping request, come back later */
spin_unlock_irq(&rrpc->inflights.lock);
return 1;
}
}
r->l_start = laddr;
r->l_end = laddr_end;
list_add_tail(&r->list, &rrpc->inflights.reqs);
spin_unlock_irq(&rrpc->inflights.lock);
return 0;
}
static inline int rrpc_lock_laddr(struct rrpc *rrpc, sector_t laddr,
unsigned pages,
struct rrpc_inflight_rq *r)
{
BUG_ON((laddr + pages) > rrpc->nr_pages);
return __rrpc_lock_laddr(rrpc, laddr, pages, r);
}
static inline struct rrpc_inflight_rq *rrpc_get_inflight_rq(struct nvm_rq *rqd)
{
struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
return &rrqd->inflight_rq;
}
static inline int rrpc_lock_rq(struct rrpc *rrpc, struct bio *bio,
struct nvm_rq *rqd)
{
sector_t laddr = rrpc_get_laddr(bio);
unsigned int pages = rrpc_get_pages(bio);
struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
return rrpc_lock_laddr(rrpc, laddr, pages, r);
}
static inline void rrpc_unlock_laddr(struct rrpc *rrpc,
struct rrpc_inflight_rq *r)
{
unsigned long flags;
spin_lock_irqsave(&rrpc->inflights.lock, flags);
list_del_init(&r->list);
spin_unlock_irqrestore(&rrpc->inflights.lock, flags);
}
static inline void rrpc_unlock_rq(struct rrpc *rrpc, struct nvm_rq *rqd)
{
struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
uint8_t pages = rqd->nr_pages;
BUG_ON((r->l_start + pages) > rrpc->nr_pages);
rrpc_unlock_laddr(rrpc, r);
}
#endif /* RRPC_H_ */