From 8e2e00473598dd5379d8408cb974dade000acafc Mon Sep 17 00:00:00 2001 From: Bob Peterson Date: Thu, 19 Jul 2012 08:12:40 -0400 Subject: 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 Signed-off-by: Steven Whitehouse --- fs/gfs2/incore.h | 49 +++++++++++++++++++++++++++++++++++++------------ 1 file changed, 37 insertions(+), 12 deletions(-) (limited to 'fs/gfs2/incore.h') diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h index dc730700b3b4..aaecc8085fc5 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; -- cgit v1.2.3-55-g7522