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authorBob Peterson <rpeterso@redhat.com>2012-07-19 08:12:40 -0400
committerSteven Whitehouse <swhiteho@redhat.com>2012-07-19 14:51:08 +0100
commit8e2e00473598dd5379d8408cb974dade000acafc (patch)
tree1f7bfdf0d07b6c0315bbd11ffee174742d66a459 /fs/gfs2/incore.h
parent294f2ad5a545eb71d397623743ddd8201131bdad (diff)
GFS2: Reduce file fragmentation
This patch reduces GFS2 file fragmentation by pre-reserving blocks. The resulting improved on disk layout greatly speeds up operations in cases which would have resulted in interlaced allocation of blocks previously. A typical example of this is 10 parallel dd processes, each writing to a file in a common dirctory. The implementation uses an rbtree of reservations attached to each resource group (and each inode). Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'fs/gfs2/incore.h')
-rw-r--r--fs/gfs2/incore.h49
1 files changed, 37 insertions, 12 deletions
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index dc730700b3b..aaecc8085fc 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -84,6 +84,7 @@ struct gfs2_rgrpd {
u32 rd_data; /* num of data blocks in rgrp */
u32 rd_bitbytes; /* number of bytes in data bitmaps */
u32 rd_free;
+ u32 rd_reserved; /* number of blocks reserved */
u32 rd_free_clone;
u32 rd_dinodes;
u64 rd_igeneration;
@@ -96,6 +97,9 @@ struct gfs2_rgrpd {
#define GFS2_RDF_UPTODATE 0x20000000 /* rg is up to date */
#define GFS2_RDF_ERROR 0x40000000 /* error in rg */
#define GFS2_RDF_MASK 0xf0000000 /* mask for internal flags */
+ spinlock_t rd_rsspin; /* protects reservation related vars */
+ struct rb_root rd_rstree; /* multi-block reservation tree */
+ u32 rd_rs_cnt; /* count of current reservations */
};
enum gfs2_state_bits {
@@ -233,6 +237,38 @@ struct gfs2_holder {
unsigned long gh_ip;
};
+/* Resource group multi-block reservation, in order of appearance:
+
+ Step 1. Function prepares to write, allocates a mb, sets the size hint.
+ Step 2. User calls inplace_reserve to target an rgrp, sets the rgrp info
+ Step 3. Function get_local_rgrp locks the rgrp, determines which bits to use
+ Step 4. Bits are assigned from the rgrp based on either the reservation
+ or wherever it can.
+*/
+
+struct gfs2_blkreserv {
+ /* components used during write (step 1): */
+ atomic_t rs_sizehint; /* hint of the write size */
+
+ /* components used during inplace_reserve (step 2): */
+ u32 rs_requested; /* Filled in by caller of gfs2_inplace_reserve() */
+
+ /* components used during get_local_rgrp (step 3): */
+ struct gfs2_rgrpd *rs_rgd; /* pointer to the gfs2_rgrpd */
+ struct gfs2_holder rs_rgd_gh; /* Filled in by get_local_rgrp */
+ struct rb_node rs_node; /* link to other block reservations */
+
+ /* components used during block searches and assignments (step 4): */
+ struct gfs2_bitmap *rs_bi; /* bitmap for the current allocation */
+ u32 rs_biblk; /* start block relative to the bi */
+ u32 rs_free; /* how many blocks are still free */
+
+ /* ancillary quota stuff */
+ struct gfs2_quota_data *rs_qa_qd[2 * MAXQUOTAS];
+ struct gfs2_holder rs_qa_qd_ghs[2 * MAXQUOTAS];
+ unsigned int rs_qa_qd_num;
+};
+
enum {
GLF_LOCK = 1,
GLF_DEMOTE = 3,
@@ -290,16 +326,6 @@ struct gfs2_glock {
#define GFS2_MIN_LVB_SIZE 32 /* Min size of LVB that gfs2 supports */
-struct gfs2_blkreserv {
- u32 rs_requested; /* Filled in by caller of gfs2_inplace_reserve() */
- struct gfs2_holder rs_rgd_gh; /* Filled in by gfs2_inplace_reserve() */
-
- /* ancillary quota stuff */
- struct gfs2_quota_data *rs_qa_qd[2 * MAXQUOTAS];
- struct gfs2_holder rs_qa_qd_ghs[2 * MAXQUOTAS];
- unsigned int rs_qa_qd_num;
-};
-
enum {
GIF_INVALID = 0,
GIF_QD_LOCKED = 1,
@@ -307,7 +333,6 @@ enum {
GIF_SW_PAGED = 3,
};
-
struct gfs2_inode {
struct inode i_inode;
u64 i_no_addr;
@@ -318,7 +343,7 @@ struct gfs2_inode {
struct gfs2_glock *i_gl; /* Move into i_gh? */
struct gfs2_holder i_iopen_gh;
struct gfs2_holder i_gh; /* for prepare/commit_write only */
- struct gfs2_blkreserv *i_res; /* resource group block reservation */
+ struct gfs2_blkreserv *i_res; /* rgrp multi-block reservation */
struct gfs2_rgrpd *i_rgd;
u64 i_goal; /* goal block for allocations */
struct rw_semaphore i_rw_mutex;