linux_dsm_epyc7002/include/linux/nvme.h
Jens Axboe ac3dd5bd12 NVMe: avoid kmalloc/kfree for smaller IO
Currently we allocate an nvme_iod for each IO, which holds the
sg list, prps, and other IO related info. Set a threshold of
2 pages and/or 8KB of data, below which we can just embed this
in the per-command pdu in blk-mq. For any IO at or below
NVME_INT_PAGES and NVME_INT_BYTES, we save a kmalloc and kfree.

For higher IOPS, this saves up to 1% of CPU time.

Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
2015-01-29 09:25:34 -08:00

180 lines
5.1 KiB
C

/*
* Definitions for the NVM Express interface
* Copyright (c) 2011-2014, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*/
#ifndef _LINUX_NVME_H
#define _LINUX_NVME_H
#include <uapi/linux/nvme.h>
#include <linux/pci.h>
#include <linux/miscdevice.h>
#include <linux/kref.h>
#include <linux/blk-mq.h>
struct nvme_bar {
__u64 cap; /* Controller Capabilities */
__u32 vs; /* Version */
__u32 intms; /* Interrupt Mask Set */
__u32 intmc; /* Interrupt Mask Clear */
__u32 cc; /* Controller Configuration */
__u32 rsvd1; /* Reserved */
__u32 csts; /* Controller Status */
__u32 rsvd2; /* Reserved */
__u32 aqa; /* Admin Queue Attributes */
__u64 asq; /* Admin SQ Base Address */
__u64 acq; /* Admin CQ Base Address */
};
#define NVME_CAP_MQES(cap) ((cap) & 0xffff)
#define NVME_CAP_TIMEOUT(cap) (((cap) >> 24) & 0xff)
#define NVME_CAP_STRIDE(cap) (((cap) >> 32) & 0xf)
#define NVME_CAP_MPSMIN(cap) (((cap) >> 48) & 0xf)
#define NVME_CAP_MPSMAX(cap) (((cap) >> 52) & 0xf)
enum {
NVME_CC_ENABLE = 1 << 0,
NVME_CC_CSS_NVM = 0 << 4,
NVME_CC_MPS_SHIFT = 7,
NVME_CC_ARB_RR = 0 << 11,
NVME_CC_ARB_WRRU = 1 << 11,
NVME_CC_ARB_VS = 7 << 11,
NVME_CC_SHN_NONE = 0 << 14,
NVME_CC_SHN_NORMAL = 1 << 14,
NVME_CC_SHN_ABRUPT = 2 << 14,
NVME_CC_SHN_MASK = 3 << 14,
NVME_CC_IOSQES = 6 << 16,
NVME_CC_IOCQES = 4 << 20,
NVME_CSTS_RDY = 1 << 0,
NVME_CSTS_CFS = 1 << 1,
NVME_CSTS_SHST_NORMAL = 0 << 2,
NVME_CSTS_SHST_OCCUR = 1 << 2,
NVME_CSTS_SHST_CMPLT = 2 << 2,
NVME_CSTS_SHST_MASK = 3 << 2,
};
#define NVME_VS(major, minor) (major << 16 | minor)
extern unsigned char nvme_io_timeout;
#define NVME_IO_TIMEOUT (nvme_io_timeout * HZ)
/*
* Represents an NVM Express device. Each nvme_dev is a PCI function.
*/
struct nvme_dev {
struct list_head node;
struct nvme_queue **queues;
struct request_queue *admin_q;
struct blk_mq_tag_set tagset;
struct blk_mq_tag_set admin_tagset;
u32 __iomem *dbs;
struct pci_dev *pci_dev;
struct dma_pool *prp_page_pool;
struct dma_pool *prp_small_pool;
int instance;
unsigned queue_count;
unsigned online_queues;
unsigned max_qid;
int q_depth;
u32 db_stride;
u32 ctrl_config;
struct msix_entry *entry;
struct nvme_bar __iomem *bar;
struct list_head namespaces;
struct kref kref;
struct miscdevice miscdev;
work_func_t reset_workfn;
struct work_struct reset_work;
char name[12];
char serial[20];
char model[40];
char firmware_rev[8];
u32 max_hw_sectors;
u32 stripe_size;
u32 page_size;
u16 oncs;
u16 abort_limit;
u8 event_limit;
u8 vwc;
u8 initialized;
};
/*
* An NVM Express namespace is equivalent to a SCSI LUN
*/
struct nvme_ns {
struct list_head list;
struct nvme_dev *dev;
struct request_queue *queue;
struct gendisk *disk;
unsigned ns_id;
int lba_shift;
int ms;
u64 mode_select_num_blocks;
u32 mode_select_block_len;
};
/*
* The nvme_iod describes the data in an I/O, including the list of PRP
* entries. You can't see it in this data structure because C doesn't let
* me express that. Use nvme_alloc_iod to ensure there's enough space
* allocated to store the PRP list.
*/
struct nvme_iod {
unsigned long private; /* For the use of the submitter of the I/O */
int npages; /* In the PRP list. 0 means small pool in use */
int offset; /* Of PRP list */
int nents; /* Used in scatterlist */
int length; /* Of data, in bytes */
dma_addr_t first_dma;
struct scatterlist sg[0];
};
static inline u64 nvme_block_nr(struct nvme_ns *ns, sector_t sector)
{
return (sector >> (ns->lba_shift - 9));
}
/**
* nvme_free_iod - frees an nvme_iod
* @dev: The device that the I/O was submitted to
* @iod: The memory to free
*/
void nvme_free_iod(struct nvme_dev *dev, struct nvme_iod *iod);
int nvme_setup_prps(struct nvme_dev *, struct nvme_iod *, int, gfp_t);
struct nvme_iod *nvme_map_user_pages(struct nvme_dev *dev, int write,
unsigned long addr, unsigned length);
void nvme_unmap_user_pages(struct nvme_dev *dev, int write,
struct nvme_iod *iod);
int nvme_submit_io_cmd(struct nvme_dev *, struct nvme_ns *,
struct nvme_command *, u32 *);
int nvme_submit_flush_data(struct nvme_queue *nvmeq, struct nvme_ns *ns);
int nvme_submit_admin_cmd(struct nvme_dev *, struct nvme_command *,
u32 *result);
int nvme_identify(struct nvme_dev *, unsigned nsid, unsigned cns,
dma_addr_t dma_addr);
int nvme_get_features(struct nvme_dev *dev, unsigned fid, unsigned nsid,
dma_addr_t dma_addr, u32 *result);
int nvme_set_features(struct nvme_dev *dev, unsigned fid, unsigned dword11,
dma_addr_t dma_addr, u32 *result);
struct sg_io_hdr;
int nvme_sg_io(struct nvme_ns *ns, struct sg_io_hdr __user *u_hdr);
int nvme_sg_io32(struct nvme_ns *ns, unsigned long arg);
int nvme_sg_get_version_num(int __user *ip);
#endif /* _LINUX_NVME_H */