PERFORCE change 179311 for review
Zheng Liu
lz at FreeBSD.org
Tue Jun 8 06:24:19 UTC 2010
http://p4web.freebsd.org/@@179311?ac=10
Change 179311 by lz at gnehzuil-freebsd on 2010/06/08 06:23:32
Dynamiclly adjust the size of reservation window.
Affected files ...
.. //depot/projects/soc2010/extfs/src/sys/fs/ext2fs/ext2_alloc.c#22 edit
.. //depot/projects/soc2010/extfs/src/sys/fs/ext2fs/ext2_rsv_win.h#10 edit
Differences ...
==== //depot/projects/soc2010/extfs/src/sys/fs/ext2fs/ext2_alloc.c#22 (text+ko) ====
@@ -52,6 +52,7 @@
#include <fs/ext2fs/ext2_extern.h>
#include <fs/ext2fs/ext2_rsv_win.h>
+/* Just for clear */
#define phy_blk(cg, fs) (((cg) * (fs->e2fs->e2fs_fpg)) + fs->e2fs->e2fs_first_dblock)
static daddr_t ext2_alloccg(struct inode *, int, daddr_t, int);
@@ -68,15 +69,40 @@
static int ext2_alloc_new_rsv(struct inode *, int, struct buf *, int32_t);
static int ext2_bpref_in_rsv(struct ext2_rsv_win *, int32_t);
static int ext2_find_rsv(struct ext2_rsv_win *, struct ext2_rsv_win *,
- struct m_ext2fs *, int32_t, int);
+ struct m_ext2fs *, int32_t, int);
static void ext2_remove_rsv_win(struct m_ext2fs *, struct ext2_rsv_win *);
-static u_long ext2_rsvalloc(struct m_ext2fs *, struct inode *, int,
- struct buf *, int32_t, int);
+static u_long ext2_rsvalloc(struct m_ext2fs *, struct inode *,
+ int, struct buf *, int32_t, int);
static daddr_t ext2_search_next_block(struct m_ext2fs *, char *, int, int);
static struct ext2_rsv_win *ext2_search_rsv(struct ext2_rsv_win_tree *, int32_t);
RB_GENERATE(ext2_rsv_win_tree, ext2_rsv_win, rsv_link, ext2_rsv_win_cmp);
+/*
+ * Allocate a block in the file system.
+ *
+ * By given preference:
+ * It checks whether inode has a reservation window and preference
+ * is within it. If so, it will try to allocate a free block from
+ * this reservation window.
+ * Otherwise, it traverses RB tree to find a place, which is not
+ * in any window. then it inserts it to RB tree and tries to allocate
+ * a free block again.
+ * If fails, it will try to allocate a free block in other cylinder
+ * groups without perference.
+ */
+
+/*
+ * Allocate a free block.
+ *
+ * Firstly it checks whether reservation window is used.
+ * If it use reservation window, it will try to allocate a free
+ * block from the reservation window. If failed, it will traverse
+ * the bitmap to find a free block.
+ * If it not use reservation window, it will try to allocate
+ * a free block by bpref. If failed, it will traverse the bitmap
+ * to find a free block.
+ */
static u_long
ext2_alloc_blk(struct inode *ip, int cg, struct buf *bp,
int32_t bpref, struct ext2_rsv_win *rp)
@@ -96,19 +122,34 @@
if (bpref < 0)
bpref = 0;
+ /* Check whther it use reservation window */
if (rp != NULL) {
+ /*
+ * If window's start is not in this cylinder group,
+ * try to allocate from the beginning of this group.
+ * Otherwise, try to allocate from the beginning of
+ * the window.
+ */
if (dtog(fs, rp->rsv_start) != cg)
start = phy_blk(cg, fs);
else
start = rp->rsv_start;
+
+ /*
+ * If window's end cross the end of this group,
+ * set end variable to the end of this group.
+ * Otherwise, set it to window's end.
+ */
if (dtog(fs, rp->rsv_end) != cg)
end = fs->e2fs->e2fs_fpg;
else
end = rp->rsv_end;
+ /* If preference block is within the window, try to allocate it. */
if (start <= bpref && bpref <= end) {
bpref = dtogd(fs, bpref);
if (isclr(bbp, bpref)) {
+ rp->rsv_alloc_hit++;
bno = bpref;
goto gotit;
}
@@ -156,7 +197,7 @@
/*
* If malloc failed, we just do not use
- * reservation window mechanism
+ * reservation window mechanism.
*/
if (rp == NULL)
return;
@@ -210,6 +251,9 @@
rp->rsv_alloc_hit = 0;
}
+/*
+ * Check bpref is in the reservation window.
+ */
static int
ext2_bpref_in_rsv(struct ext2_rsv_win *rp, int32_t bpref)
{
@@ -219,6 +263,10 @@
return (1);
}
+/*
+ * Search a tree node from RB tree. It includes the bpref or
+ * the previous one if bpref is not in any window.
+ */
static struct ext2_rsv_win *
ext2_search_rsv(struct ext2_rsv_win_tree *root, int32_t start)
{
@@ -247,6 +295,10 @@
return (prev);
}
+/*
+ * Find a reservation window by given range from start to
+ * the end of this cylinder group.
+ */
static int
ext2_find_rsv(struct ext2_rsv_win *search, struct ext2_rsv_win *rp,
struct m_ext2fs *fs, int32_t start, int cg)
@@ -265,6 +317,11 @@
return (0);
}
+ /*
+ * Make the start of reservation window byte-aligned
+ * in order to can find a free block with bit operations
+ * in ext2_search_next_block() function.
+ */
cur = start & ~7;
rsv = search;
prev = NULL;
@@ -299,6 +356,10 @@
return (0);
}
+/*
+ * Find a free block by given range from bpref to
+ * the end of this cylinder group.
+ */
static daddr_t
ext2_search_next_block(struct m_ext2fs *fs, char *bbp, int bpref, int cg)
{
@@ -322,6 +383,9 @@
return (-1);
}
+/*
+ * Allocate a new reservation window.
+ */
static int
ext2_alloc_new_rsv(struct inode *ip, int cg, struct buf *bp, int32_t bpref)
{
@@ -340,6 +404,17 @@
else
start = bpref;
+ /* Dynamically increase the size of window */
+ if (rp->rsv_end != EXT2_RSV_NOT_ALLOCATED) {
+ if (rp->rsv_alloc_hit >
+ ((rp->rsv_end - rp->rsv_start + 1) / 2)) {
+ size = size * 2;
+ if (size > EXT2_RSV_MAX_RESERVE_BLKS)
+ size = EXT2_RSV_MAX_RESERVE_BLKS;
+ rp->rsv_goal_size = size;
+ }
+ }
+
EXT2_TREE_LOCK(fs);
search = ext2_search_rsv(&fs->e2fs_rsv_tree, start);
@@ -502,38 +577,6 @@
return EIO;
}
-/*
- * Allocate a block in the file system.
- *
- * A preference may be optionally specified. If a preference is given
- * the following hierarchy is used to allocate a block:
- * 1) allocate the requested block.
- * 2) allocate a rotationally optimal block in the same cylinder.
- * 3) allocate a block in the same cylinder group.
- * 4) quadradically rehash into other cylinder groups, until an
- * available block is located.
- * If no block preference is given the following hierarchy is used
- * to allocate a block:
- * 1) allocate a block in the cylinder group that contains the
- * inode for the file.
- * 2) quadradically rehash into other cylinder groups, until an
- * available block is located.
- *
- * A preference may be optionally specified. If a preference is given
- * the following hierarchy is used to allocate a block:
- * 1) allocate the requested block.
- * 2) allocate a rotationally optimal block in the same cylinder.
- * 3) allocate a block in the same cylinder group.
- * 4) quadradically rehash into other cylinder groups, until an
- * available block is located.
- * If no block preference is given the following hierarchy is used
- * to allocate a block:
- * 1) allocate a block in the cylinder group that contains the
- * inode for the file.
- * 2) quadradically rehash into other cylinder groups, until an
- * available block is located.
- */
-
int
ext2_alloc(ip, lbn, bpref, size, cred, bnp)
struct inode *ip;
==== //depot/projects/soc2010/extfs/src/sys/fs/ext2fs/ext2_rsv_win.h#10 (text+ko) ====
@@ -31,7 +31,7 @@
#include <sys/tree.h>
#define EXT2_RSV_DEFAULT_RESERVE_BLKS 8
-#define EXT2_RSV_MAX_RESERVE_BLKS 1027
+#define EXT2_RSV_MAX_RESERVE_BLKS 1024
#define EXT2_RSV_NOT_ALLOCATED 0
#define EXT2_RSV_LOCK(ip) mtx_lock(&ip->i_rsv_lock)
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