linux/fs/ocfs2/suballoc.h
Mark Fasheh 9c7af40b21 ocfs2: throttle back local alloc when low on disk space
Ocfs2's local allocator disables itself for the duration of a mount point
when it has trouble allocating a large enough area from the primary bitmap.
That can cause performance problems, especially for disks which were only
temporarily full or fragmented. This patch allows for the allocator to
shrink it's window first, before being disabled. Later, it can also be
re-enabled so that any performance drop is minimized.

To do this, we allow the value of osb->local_alloc_bits to be shrunk when
needed. The default value is recorded in a mostly read-only variable so that
we can re-initialize when required.

Locking had to be updated so that we could protect changes to
local_alloc_bits. Mostly this involves protecting various local alloc values
with the osb spinlock. A new state is also added, OCFS2_LA_THROTTLED, which
is used when the local allocator is has shrunk, but is not disabled. If the
available space dips below 1 megabyte, the local alloc file is disabled. In
either case, local alloc is re-enabled 30 seconds after the event, or when
an appropriate amount of bits is seen in the primary bitmap.

Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-10-13 13:57:57 -07:00

161 lines
4.9 KiB
C

/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* suballoc.h
*
* Defines sub allocator api
*
* Copyright (C) 2003, 2004 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#ifndef _CHAINALLOC_H_
#define _CHAINALLOC_H_
typedef int (group_search_t)(struct inode *,
struct buffer_head *,
u32,
u32,
u16 *,
u16 *);
struct ocfs2_alloc_context {
struct inode *ac_inode; /* which bitmap are we allocating from? */
struct buffer_head *ac_bh; /* file entry bh */
u32 ac_alloc_slot; /* which slot are we allocating from? */
u32 ac_bits_wanted;
u32 ac_bits_given;
#define OCFS2_AC_USE_LOCAL 1
#define OCFS2_AC_USE_MAIN 2
#define OCFS2_AC_USE_INODE 3
#define OCFS2_AC_USE_META 4
u32 ac_which;
/* these are used by the chain search */
u16 ac_chain;
int ac_allow_chain_relink;
group_search_t *ac_group_search;
u64 ac_last_group;
};
void ocfs2_free_alloc_context(struct ocfs2_alloc_context *ac);
static inline int ocfs2_alloc_context_bits_left(struct ocfs2_alloc_context *ac)
{
return ac->ac_bits_wanted - ac->ac_bits_given;
}
int ocfs2_reserve_new_metadata(struct ocfs2_super *osb,
struct ocfs2_dinode *fe,
struct ocfs2_alloc_context **ac);
int ocfs2_reserve_new_inode(struct ocfs2_super *osb,
struct ocfs2_alloc_context **ac);
int ocfs2_reserve_clusters(struct ocfs2_super *osb,
u32 bits_wanted,
struct ocfs2_alloc_context **ac);
int ocfs2_claim_metadata(struct ocfs2_super *osb,
handle_t *handle,
struct ocfs2_alloc_context *ac,
u32 bits_wanted,
u16 *suballoc_bit_start,
u32 *num_bits,
u64 *blkno_start);
int ocfs2_claim_new_inode(struct ocfs2_super *osb,
handle_t *handle,
struct ocfs2_alloc_context *ac,
u16 *suballoc_bit,
u64 *fe_blkno);
int ocfs2_claim_clusters(struct ocfs2_super *osb,
handle_t *handle,
struct ocfs2_alloc_context *ac,
u32 min_clusters,
u32 *cluster_start,
u32 *num_clusters);
/*
* Use this variant of ocfs2_claim_clusters to specify a maxiumum
* number of clusters smaller than the allocation reserved.
*/
int __ocfs2_claim_clusters(struct ocfs2_super *osb,
handle_t *handle,
struct ocfs2_alloc_context *ac,
u32 min_clusters,
u32 max_clusters,
u32 *cluster_start,
u32 *num_clusters);
int ocfs2_free_suballoc_bits(handle_t *handle,
struct inode *alloc_inode,
struct buffer_head *alloc_bh,
unsigned int start_bit,
u64 bg_blkno,
unsigned int count);
int ocfs2_free_dinode(handle_t *handle,
struct inode *inode_alloc_inode,
struct buffer_head *inode_alloc_bh,
struct ocfs2_dinode *di);
int ocfs2_free_clusters(handle_t *handle,
struct inode *bitmap_inode,
struct buffer_head *bitmap_bh,
u64 start_blk,
unsigned int num_clusters);
static inline u64 ocfs2_which_suballoc_group(u64 block, unsigned int bit)
{
u64 group = block - (u64) bit;
return group;
}
static inline u32 ocfs2_cluster_from_desc(struct ocfs2_super *osb,
u64 bg_blkno)
{
/* This should work for all block group descriptors as only
* the 1st group descriptor of the cluster bitmap is
* different. */
if (bg_blkno == osb->first_cluster_group_blkno)
return 0;
/* the rest of the block groups are located at the beginning
* of their 1st cluster, so a direct translation just
* works. */
return ocfs2_blocks_to_clusters(osb->sb, bg_blkno);
}
static inline int ocfs2_is_cluster_bitmap(struct inode *inode)
{
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
return osb->bitmap_blkno == OCFS2_I(inode)->ip_blkno;
}
/* This is for local alloc ONLY. Others should use the task-specific
* apis above. */
int ocfs2_reserve_cluster_bitmap_bits(struct ocfs2_super *osb,
struct ocfs2_alloc_context *ac);
void ocfs2_free_ac_resource(struct ocfs2_alloc_context *ac);
/* given a cluster offset, calculate which block group it belongs to
* and return that block offset. */
u64 ocfs2_which_cluster_group(struct inode *inode, u32 cluster);
/* somewhat more expensive than our other checks, so use sparingly. */
int ocfs2_check_group_descriptor(struct super_block *sb,
struct ocfs2_dinode *di,
struct ocfs2_group_desc *gd);
#endif /* _CHAINALLOC_H_ */