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authorKrutika Dhananjay <kdhananj@redhat.com>2016-06-07 16:27:34 +0530
committerPranith Kumar Karampuri <pkarampu@redhat.com>2016-06-29 21:37:08 -0700
commitaf1ab7266edf91216e27484c505c78401f092e13 (patch)
tree3fe0f59fb515fe3ae946c9d02d7a3dd762dda32c /libglusterfs
parent4d62806d3031cea33bab1641e0c14a1a8cb11c46 (diff)
libglusterfs: Implement API that provides page-aligned iobufs
Backport of: http://review.gluster.org/14672 One of the consumers of a page aligned buffer would be posix's readv fop on O_DIRECT fds. Today the way it works is by getting a page-aligned buffer through calloc, pread()ing into this buffer and then copying its contents into a newly created iobuf's ptr. This results in an extra memcpy() which can be avoided if we could implement an api that would return an iobuf whose ptr is page-aligned. That way the iobuf->ptr can be directly passed to sys_pread() as a parameter by posix translator. Change-Id: Ie44c300dc773fef8e1669d609987d47dbd340ac2 BUG: 1351024 Signed-off-by: Krutika Dhananjay <kdhananj@redhat.com> Reviewed-on: http://review.gluster.org/14826 Smoke: Gluster Build System <jenkins@build.gluster.org> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org> CentOS-regression: Gluster Build System <jenkins@build.gluster.org> Reviewed-by: Zhou Zhengping <johnzzpcrystal@gmail.com> Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Diffstat (limited to 'libglusterfs')
-rw-r--r--libglusterfs/src/iobuf.c35
-rw-r--r--libglusterfs/src/iobuf.h4
2 files changed, 39 insertions, 0 deletions
diff --git a/libglusterfs/src/iobuf.c b/libglusterfs/src/iobuf.c
index a4d3669..b2df0dc 100644
--- a/libglusterfs/src/iobuf.c
+++ b/libglusterfs/src/iobuf.c
@@ -679,6 +679,36 @@ unlock:
}
struct iobuf *
+iobuf_get_page_aligned (struct iobuf_pool *iobuf_pool, size_t page_size,
+ size_t align_size)
+{
+ size_t req_size = 0;
+ struct iobuf *iobuf = NULL;
+
+ req_size = page_size;
+
+ if (req_size == 0) {
+ req_size = iobuf_pool->default_page_size;
+ }
+
+ iobuf = iobuf_get2 (iobuf_pool, req_size + align_size);
+ /* If std allocation was used, then free_ptr will be non-NULL. In this
+ * case, we do not want to modify the original free_ptr.
+ * On the other hand, if the buf was gotten through the available
+ * arenas, then we use iobuf->free_ptr to store the original
+ * pointer to the offset into the mmap'd block of memory and in turn
+ * reuse iobuf->ptr to hold the page-aligned address. And finally, in
+ * iobuf_put(), we copy iobuf->free_ptr into iobuf->ptr - back to where
+ * it was originally when __iobuf_get() returned this iobuf.
+ */
+ if (!iobuf->free_ptr)
+ iobuf->free_ptr = iobuf->ptr;
+ iobuf->ptr = GF_ALIGN_BUF (iobuf->ptr, align_size);
+
+ return iobuf;
+}
+
+struct iobuf *
iobuf_get (struct iobuf_pool *iobuf_pool)
{
struct iobuf *iobuf = NULL;
@@ -745,6 +775,11 @@ __iobuf_put (struct iobuf *iobuf, struct iobuf_arena *iobuf_arena)
list_del_init (&iobuf->list);
iobuf_arena->active_cnt--;
+ if (iobuf->free_ptr) {
+ iobuf->ptr = iobuf->free_ptr;
+ iobuf->free_ptr = NULL;
+ }
+
list_add (&iobuf->list, &iobuf_arena->passive.list);
iobuf_arena->passive_cnt++;
diff --git a/libglusterfs/src/iobuf.h b/libglusterfs/src/iobuf.h
index 7e5cfe3..1578ceb 100644
--- a/libglusterfs/src/iobuf.h
+++ b/libglusterfs/src/iobuf.h
@@ -169,4 +169,8 @@ void iobuf_stats_dump (struct iobuf_pool *iobuf_pool);
struct iobuf *
iobuf_get2 (struct iobuf_pool *iobuf_pool, size_t page_size);
+
+struct iobuf *
+iobuf_get_page_aligned (struct iobuf_pool *iobuf_pool, size_t page_size,
+ size_t align_size);
#endif /* !_IOBUF_H_ */