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authorKrutika Dhananjay <kdhananj@redhat.com>2016-06-07 16:27:34 +0530
committerJeff Darcy <jdarcy@redhat.com>2016-06-28 14:52:42 -0700
commit1e60f9746cf7cb8ce34e2b1572410c39b11d7664 (patch)
tree82c839e73e452222a2b9445c535d0241306bcf41 /libglusterfs
parent60cc8ddaf6105b89e5ce3222c5c5a014deda6a15 (diff)
libglusterfs: Implement API that provides page-aligned iobufs
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: I385139bc6ee309fc501034b3af8f7814fab8cd65 BUG: 1343838 Signed-off-by: Krutika Dhananjay <kdhananj@redhat.com> Reviewed-on: http://review.gluster.org/14672 CentOS-regression: Gluster Build System <jenkins@build.gluster.org> Smoke: Gluster Build System <jenkins@build.gluster.org> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org> Reviewed-by: Zhou Zhengping <johnzzpcrystal@gmail.com> Reviewed-by: Jeff Darcy <jdarcy@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 d1eb0acaf5e..17cd68fc206 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 7e5cfe37a28..1578ceb84dd 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_ */