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authorDave Chinner <dchinner@redhat.com>2013-08-12 20:50:05 +1000
committerBen Myers <bpm@sgi.com>2013-08-13 16:12:30 -0500
commit7492c5b42de857c13d8b7e0dafb2a5e331598e00 (patch)
tree95a073b09c3ec9105bb33d1ee0cbbe28f2f78f9c /fs/xfs
parent166d13688a0e2d0aa379e259af8e2ee6a401de9a (diff)
xfs: Reduce allocations during CIL insertion
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>
Diffstat (limited to 'fs/xfs')
-rw-r--r--fs/xfs/xfs_log.h1
-rw-r--r--fs/xfs/xfs_log_cil.c95
-rw-r--r--fs/xfs/xfs_trans.h1
3 files changed, 57 insertions, 40 deletions
diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h
index e63d9e10bd69..1c458487f000 100644
--- a/fs/xfs/xfs_log.h
+++ b/fs/xfs/xfs_log.h
@@ -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)
diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
index 4e108720a789..423ceaf0aeb0 100644
--- a/fs/xfs/xfs_log_cil.c
+++ b/fs/xfs/xfs_log_cil.c
@@ -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];
-
- /* 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;
+ lv->lv_iovecp = (struct xfs_log_iovec *)&lv[1];
- 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);
+ /* The allocated data region lies beyond the iovec region */
+ lv->lv_buf = (char *)lv + buf_size - nbytes;
-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;
}
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index 97144ec230e2..24bbdcd297c7 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -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)