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xfs: Reduce allocations during CIL insertion

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Now that we have the size of the object before the formatting pass
is called, we can allocation the log vector and it's buffer in a
single allocation rather than two separate allocations.

Store the size of the allocated buffer in the log vector so that
we potentially avoid allocation for future modifications of the
object.

While touching this code, remove the IOP_FORMAT definition.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
This commit is contained in:
Dave Chinner 2013-08-12 20:50:05 +10:00 committed by Ben Myers
parent 166d13688a
commit 7492c5b42d
3 changed files with 57 additions and 40 deletions
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1
fs/xfs/xfs_log.h
View File

@ -27,6 +27,7 @@ struct xfs_log_vec {
struct xfs_log_item *lv_item; /* owner */
char *lv_buf; /* formatted buffer */
int lv_buf_len; /* size of formatted buffer */
int lv_size; /* size of allocated lv */
};
#define XFS_LOG_VEC_ORDERED (-1)

95
fs/xfs/xfs_log_cil.c
View File

@ -80,6 +80,36 @@ xlog_cil_init_post_recovery(
log->l_curr_block);
}
STATIC int
xlog_cil_lv_item_format(
struct xfs_log_item *lip,
struct xfs_log_vec *lv)
{
int index;
char *ptr;
/* format new vectors into array */
lip->li_ops->iop_format(lip, lv->lv_iovecp);
/* copy data into existing array */
ptr = lv->lv_buf;
for (index = 0; index < lv->lv_niovecs; index++) {
struct xfs_log_iovec *vec = &lv->lv_iovecp[index];
memcpy(ptr, vec->i_addr, vec->i_len);
vec->i_addr = ptr;
ptr += vec->i_len;
}
/*
* some size calculations for log vectors over-estimate, so the caller
* doesn't know the amount of space actually used by the item. Return
* the byte count to the caller so they can check and store it
* appropriately.
*/
return ptr - lv->lv_buf;
}
/*
* Format log item into a flat buffers
*
@ -111,7 +141,7 @@ xlog_cil_prepare_log_vecs(
struct xfs_trans *tp)
{
struct xfs_log_item_desc *lidp;
struct xfs_log_vec *lv = NULL;
struct xfs_log_vec *prev_lv = NULL;
struct xfs_log_vec *ret_lv = NULL;
@ -123,12 +153,10 @@ xlog_cil_prepare_log_vecs(
list_for_each_entry(lidp, &tp->t_items, lid_trans) {
struct xfs_log_item *lip = lidp->lid_item;
struct xfs_log_vec *new_lv;
void *ptr;
int index;
int len = 0;
uint niovecs = 0;
uint nbytes = 0;
struct xfs_log_vec *lv;
int niovecs = 0;
int nbytes = 0;
int buf_size;
bool ordered = false;
/* Skip items which aren't dirty in this transaction. */
@ -150,48 +178,39 @@ xlog_cil_prepare_log_vecs(
if (niovecs == XFS_LOG_VEC_ORDERED) {
ordered = true;
niovecs = 0;
nbytes = 0;
}
new_lv = kmem_zalloc(sizeof(*new_lv) +
niovecs * sizeof(struct xfs_log_iovec),
KM_SLEEP|KM_NOFS);
/* calc buffer size */
buf_size = sizeof(struct xfs_log_vec) + nbytes +
niovecs * sizeof(struct xfs_log_iovec);
new_lv->lv_item = lip;
new_lv->lv_niovecs = niovecs;
/* allocate new data chunk */
lv = kmem_zalloc(buf_size, KM_SLEEP|KM_NOFS);
lv->lv_item = lip;
lv->lv_size = buf_size;
lv->lv_niovecs = niovecs;
if (ordered) {
/* track as an ordered logvec */
new_lv->lv_buf_len = XFS_LOG_VEC_ORDERED;
goto next;
ASSERT(lip->li_lv == NULL);
lv->lv_buf_len = XFS_LOG_VEC_ORDERED;
goto insert;
}
/* The allocated iovec region lies beyond the log vector. */
new_lv->lv_iovecp = (struct xfs_log_iovec *)&new_lv[1];
lv->lv_iovecp = (struct xfs_log_iovec *)&lv[1];
/* build the vector array and calculate it's length */
IOP_FORMAT(new_lv->lv_item, new_lv->lv_iovecp);
for (index = 0; index < new_lv->lv_niovecs; index++)
len += new_lv->lv_iovecp[index].i_len;
/* The allocated data region lies beyond the iovec region */
lv->lv_buf = (char *)lv + buf_size - nbytes;
new_lv->lv_buf_len = len;
new_lv->lv_buf = kmem_alloc(new_lv->lv_buf_len,
KM_SLEEP|KM_NOFS);
ptr = new_lv->lv_buf;
for (index = 0; index < new_lv->lv_niovecs; index++) {
struct xfs_log_iovec *vec = &new_lv->lv_iovecp[index];
memcpy(ptr, vec->i_addr, vec->i_len);
vec->i_addr = ptr;
ptr += vec->i_len;
}
ASSERT(ptr == new_lv->lv_buf + new_lv->lv_buf_len);
next:
lv->lv_buf_len = xlog_cil_lv_item_format(lip, lv);
ASSERT(lv->lv_buf_len <= nbytes);
insert:
if (!ret_lv)
ret_lv = new_lv;
ret_lv = lv;
else
lv->lv_next = new_lv;
lv = new_lv;
prev_lv->lv_next = lv;
prev_lv = lv;
}
return ret_lv;
@ -228,7 +247,6 @@ xfs_cil_prepare_item(
*len += lv->lv_buf_len - old->lv_buf_len;
*diff_iovecs += lv->lv_niovecs - old->lv_niovecs;
kmem_free(old->lv_buf);
kmem_free(old);
} else {
/* new lv, must pin the log item */
@ -354,7 +372,6 @@ xlog_cil_free_logvec(
for (lv = log_vector; lv; ) {
struct xfs_log_vec *next = lv->lv_next;
kmem_free(lv->lv_buf);
kmem_free(lv);
lv = next;
}

1
fs/xfs/xfs_trans.h
View File

@ -77,7 +77,6 @@ struct xfs_item_ops {
void (*iop_committing)(xfs_log_item_t *, xfs_lsn_t);
};
#define IOP_FORMAT(ip,vp) (*(ip)->li_ops->iop_format)(ip, vp)
#define IOP_PIN(ip) (*(ip)->li_ops->iop_pin)(ip)
#define IOP_UNPIN(ip, remove) (*(ip)->li_ops->iop_unpin)(ip, remove)
#define IOP_PUSH(ip, list) (*(ip)->li_ops->iop_push)(ip, list)