svn commit: r323665 - stable/11/sys/kern
Alan Cox
alc at FreeBSD.org
Sun Sep 17 04:15:13 UTC 2017
Author: alc
Date: Sun Sep 17 04:15:12 2017
New Revision: 323665
URL: https://svnweb.freebsd.org/changeset/base/323665
Log:
MFC r321423
Change the interactions of the interface functions with the "meta" and
"leaf" functions for alloc, free, and fill. After the change, the interface
functions call "meta" unconditionally, and the "meta" functions recur
unconditionally in looping over their descendants. The "meta" functions
start with a validity test, and then a test for the "leaf" case, before
falling into the general recursive case. This simplifies and shrinks the
code, and, for "free" and "fill" moves panic tests that check the same meta
node repeatedly in a loop to a place that will have each node tested once.
Remove irrelevant null checks from blist_free and blist_fill.
Make the code that initializes a meta node the same in blist_meta_alloc and
blist_meta_fill.
Parenthesize return expressions in blst_meta_fill.
Modified:
stable/11/sys/kern/subr_blist.c
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/kern/subr_blist.c
==============================================================================
--- stable/11/sys/kern/subr_blist.c Sun Sep 17 03:44:15 2017 (r323664)
+++ stable/11/sys/kern/subr_blist.c Sun Sep 17 04:15:12 2017 (r323665)
@@ -224,12 +224,8 @@ blist_alloc(blist_t bl, daddr_t count)
* reduce the hint, stopping further iterations.
*/
while (count <= bl->bl_root->bm_bighint) {
- if (bl->bl_radix == BLIST_BMAP_RADIX)
- blk = blst_leaf_alloc(bl->bl_root, 0, count,
- bl->bl_cursor);
- else
- blk = blst_meta_alloc(bl->bl_root, 0, count,
- bl->bl_radix, bl->bl_skip, bl->bl_cursor);
+ blk = blst_meta_alloc(bl->bl_root, 0, count, bl->bl_radix,
+ bl->bl_skip, bl->bl_cursor);
if (blk != SWAPBLK_NONE) {
bl->bl_cursor = blk + count;
return (blk);
@@ -260,13 +256,8 @@ blist_avail(blist_t bl)
void
blist_free(blist_t bl, daddr_t blkno, daddr_t count)
{
- if (bl) {
- if (bl->bl_radix == BLIST_BMAP_RADIX)
- blst_leaf_free(bl->bl_root, blkno, count);
- else
- blst_meta_free(bl->bl_root, blkno, count,
- bl->bl_radix, bl->bl_skip, 0);
- }
+
+ blst_meta_free(bl->bl_root, blkno, count, bl->bl_radix, bl->bl_skip, 0);
}
/*
@@ -278,17 +269,9 @@ blist_free(blist_t bl, daddr_t blkno, daddr_t count)
daddr_t
blist_fill(blist_t bl, daddr_t blkno, daddr_t count)
{
- daddr_t filled;
- if (bl) {
- if (bl->bl_radix == BLIST_BMAP_RADIX)
- filled = blst_leaf_fill(bl->bl_root, blkno, count);
- else
- filled = blst_meta_fill(bl->bl_root, blkno, count,
- bl->bl_radix, bl->bl_skip, 0);
- return (filled);
- }
- return (0);
+ return (blst_meta_fill(bl->bl_root, blkno, count, bl->bl_radix,
+ bl->bl_skip, 0));
}
/*
@@ -449,6 +432,8 @@ blst_meta_alloc(blmeta_t *scan, daddr_t blk, daddr_t c
int child;
bool scan_from_start;
+ if (radix == BLIST_BMAP_RADIX)
+ return (blst_leaf_alloc(scan, blk, count, cursor));
if (scan->u.bmu_avail < count) {
/*
* The meta node's hint must be too large if the allocation
@@ -497,14 +482,8 @@ blst_meta_alloc(blmeta_t *scan, daddr_t blk, daddr_t c
/*
* The allocation might fit in the i'th subtree.
*/
- if (next_skip == 1) {
- r = blst_leaf_alloc(&scan[i], blk, count,
- cursor > blk ? cursor : blk);
- } else {
- r = blst_meta_alloc(&scan[i], blk, count,
- radix, next_skip - 1, cursor > blk ?
- cursor : blk);
- }
+ r = blst_meta_alloc(&scan[i], blk, count, radix,
+ next_skip - 1, cursor > blk ? cursor : blk);
if (r != SWAPBLK_NONE) {
scan->u.bmu_avail -= count;
return (r);
@@ -578,6 +557,10 @@ blst_meta_free(blmeta_t *scan, daddr_t freeBlk, daddr_
daddr_t i, next_skip, v;
int child;
+ if (scan->bm_bighint == (daddr_t)-1)
+ panic("freeing invalid range");
+ if (radix == BLIST_BMAP_RADIX)
+ return (blst_leaf_free(scan, freeBlk, count));
next_skip = skip / BLIST_META_RADIX;
if (scan->u.bmu_avail == 0) {
@@ -630,17 +613,9 @@ blst_meta_free(blmeta_t *scan, daddr_t freeBlk, daddr_
v = blk + radix - freeBlk;
if (v > count)
v = count;
-
- if (scan->bm_bighint == (daddr_t)-1)
- panic("blst_meta_free: freeing unexpected range");
-
- if (next_skip == 1) {
- blst_leaf_free(&scan[i], freeBlk, v);
- } else {
- blst_meta_free(&scan[i], freeBlk, v, radix, next_skip - 1, blk);
- }
+ blst_meta_free(&scan[i], freeBlk, v, radix, next_skip - 1, blk);
if (scan->bm_bighint < scan[i].bm_bighint)
- scan->bm_bighint = scan[i].bm_bighint;
+ scan->bm_bighint = scan[i].bm_bighint;
count -= v;
freeBlk += v;
blk += radix;
@@ -763,13 +738,17 @@ blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr
daddr_t i, nblks, next_skip, v;
int child;
+ if (scan->bm_bighint == (daddr_t)-1)
+ panic("filling invalid range");
if (count > radix) {
/*
* The allocation exceeds the number of blocks that are
- * managed by this meta node.
+ * managed by this node.
*/
- panic("allocation too large");
+ panic("fill too large");
}
+ if (radix == BLIST_BMAP_RADIX)
+ return (blst_leaf_fill(scan, allocBlk, count));
if (count == radix || scan->u.bmu_avail == 0) {
/*
* ALL-ALLOCATED special case
@@ -777,7 +756,7 @@ blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr
nblks = scan->u.bmu_avail;
scan->u.bmu_avail = 0;
scan->bm_bighint = 0;
- return nblks;
+ return (nblks);
}
next_skip = skip / BLIST_META_RADIX;
@@ -793,13 +772,11 @@ blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr
* meta node cannot have a terminator in any subtree.
*/
for (i = 1; i <= skip; i += next_skip) {
- if (next_skip == 1) {
+ if (next_skip == 1)
scan[i].u.bmu_bitmap = (u_daddr_t)-1;
- scan[i].bm_bighint = BLIST_BMAP_RADIX;
- } else {
- scan[i].bm_bighint = radix;
+ else
scan[i].u.bmu_avail = radix;
- }
+ scan[i].bm_bighint = radix;
}
} else {
radix /= BLIST_META_RADIX;
@@ -813,23 +790,15 @@ blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr
v = blk + radix - allocBlk;
if (v > count)
v = count;
-
- if (scan->bm_bighint == (daddr_t)-1)
- panic("blst_meta_fill: filling unexpected range");
-
- if (next_skip == 1) {
- nblks += blst_leaf_fill(&scan[i], allocBlk, v);
- } else {
- nblks += blst_meta_fill(&scan[i], allocBlk, v,
- radix, next_skip - 1, blk);
- }
+ nblks += blst_meta_fill(&scan[i], allocBlk, v, radix,
+ next_skip - 1, blk);
count -= v;
allocBlk += v;
blk += radix;
i += next_skip;
}
scan->u.bmu_avail -= nblks;
- return nblks;
+ return (nblks);
}
/*
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