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The *_meta_* functions include a radix parameter, a blk parameter, and

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another parameter that identifies a starting point in the memory address
block.  Radix is a power of two, blk is a multiple of radix, and the
starting point is in the range [blk, blk+radix), so that blk can always be
computed from the other two.  This change drops the blk parameter from the
meta functions and computes it instead.  (On amd64, for example, this
change reduces subr_blist.o's text size by 7%.)

It also makes the radix parameters unsigned to address concerns that the
calculation of '-radix' might overflow without the -fwrapv option.  (See
https://reviews.freebsd.org/D11819.)

Submitted by:	Doug Moore <dougm@rice.edu>
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D11964
This commit is contained in:
alc 2017-08-13 16:39:49 +00:00
parent 38caa752ce
commit 6b281b98b3
2 changed files with 22 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
sys/kern/subr_blist.c
View File

@ -123,16 +123,16 @@ void panic(const char *ctl, ...);
*/
static daddr_t blst_leaf_alloc(blmeta_t *scan, daddr_t blk, int count,
daddr_t cursor);
static daddr_t blst_meta_alloc(blmeta_t *scan, daddr_t blk, daddr_t count,
daddr_t radix, daddr_t cursor);
static daddr_t blst_meta_alloc(blmeta_t *scan, daddr_t cursor, daddr_t count,
u_daddr_t radix);
static void blst_leaf_free(blmeta_t *scan, daddr_t relblk, int count);
static void blst_meta_free(blmeta_t *scan, daddr_t freeBlk, daddr_t count,
daddr_t radix, daddr_t blk);
u_daddr_t radix);
static void blst_copy(blmeta_t *scan, daddr_t blk, daddr_t radix,
blist_t dest, daddr_t count);
static daddr_t blst_leaf_fill(blmeta_t *scan, daddr_t blk, int count);
static daddr_t blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr_t count,
daddr_t radix, daddr_t blk);
u_daddr_t radix);
static daddr_t blst_radix_init(blmeta_t *scan, daddr_t radix, daddr_t count);
#ifndef _KERNEL
static void blst_radix_print(blmeta_t *scan, daddr_t blk, daddr_t radix,
@ -247,8 +247,8 @@ blist_alloc(blist_t bl, daddr_t count)
* reduce the hint, stopping further iterations.
*/
while (count <= bl->bl_root->bm_bighint) {
blk = blst_meta_alloc(bl->bl_root, 0, count, bl->bl_radix,
bl->bl_cursor);
blk = blst_meta_alloc(bl->bl_root, bl->bl_cursor, count,
bl->bl_radix);
if (blk != SWAPBLK_NONE) {
bl->bl_cursor = blk + count;
return (blk);
@ -280,7 +280,7 @@ void
blist_free(blist_t bl, daddr_t blkno, daddr_t count)
{
blst_meta_free(bl->bl_root, blkno, count, bl->bl_radix, 0);
blst_meta_free(bl->bl_root, blkno, count, bl->bl_radix);
}
/*
@ -293,7 +293,7 @@ daddr_t
blist_fill(blist_t bl, daddr_t blkno, daddr_t count)
{
return (blst_meta_fill(bl->bl_root, blkno, count, bl->bl_radix, 0));
return (blst_meta_fill(bl->bl_root, blkno, count, bl->bl_radix));
}
/*
@ -447,13 +447,13 @@ blst_leaf_alloc(blmeta_t *scan, daddr_t blk, int count, daddr_t cursor)
* and we have a few optimizations strewn in as well.
*/
static daddr_t
blst_meta_alloc(blmeta_t *scan, daddr_t blk, daddr_t count, daddr_t radix,
daddr_t cursor)
blst_meta_alloc(blmeta_t *scan, daddr_t cursor, daddr_t count, u_daddr_t radix)
{
daddr_t i, next_skip, r, skip;
daddr_t blk, i, next_skip, r, skip;
int child;
bool scan_from_start;
blk = cursor & -radix;
if (radix == BLIST_BMAP_RADIX)
return (blst_leaf_alloc(scan, blk, count, cursor));
if (scan->u.bmu_avail < count) {
@ -505,8 +505,8 @@ blst_meta_alloc(blmeta_t *scan, daddr_t blk, daddr_t count, daddr_t radix,
/*
* The allocation might fit in the i'th subtree.
*/
r = blst_meta_alloc(&scan[i], blk, count, radix,
cursor > blk ? cursor : blk);
r = blst_meta_alloc(&scan[i],
cursor > blk ? cursor : blk, count, radix);
if (r != SWAPBLK_NONE) {
scan->u.bmu_avail -= count;
return (r);
@ -574,10 +574,9 @@ blst_leaf_free(blmeta_t *scan, daddr_t blk, int count)
* range).
*/
static void
blst_meta_free(blmeta_t *scan, daddr_t freeBlk, daddr_t count, daddr_t radix,
daddr_t blk)
blst_meta_free(blmeta_t *scan, daddr_t freeBlk, daddr_t count, u_daddr_t radix)
{
daddr_t i, next_skip, skip, v;
daddr_t blk, i, next_skip, skip, v;
int child;
if (scan->bm_bighint == (daddr_t)-1)
@ -628,6 +627,7 @@ blst_meta_free(blmeta_t *scan, daddr_t freeBlk, daddr_t count, daddr_t radix,
* Break the free down into its components
*/
blk = freeBlk & -radix;
radix /= BLIST_META_RADIX;
child = (freeBlk - blk) / radix;
@ -637,7 +637,7 @@ blst_meta_free(blmeta_t *scan, daddr_t freeBlk, daddr_t count, daddr_t radix,
v = blk + radix - freeBlk;
if (v > count)
v = count;
blst_meta_free(&scan[i], freeBlk, v, radix, blk);
blst_meta_free(&scan[i], freeBlk, v, radix);
if (scan->bm_bighint < scan[i].bm_bighint)
scan->bm_bighint = scan[i].bm_bighint;
count -= v;
@ -755,10 +755,9 @@ blst_leaf_fill(blmeta_t *scan, daddr_t blk, int count)
* number of blocks allocated by the call.
*/
static daddr_t
blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr_t count, daddr_t radix,
daddr_t blk)
blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr_t count, u_daddr_t radix)
{
daddr_t i, nblks, next_skip, skip, v;
daddr_t blk, i, nblks, next_skip, skip, v;
int child;
if (scan->bm_bighint == (daddr_t)-1)
@ -783,6 +782,7 @@ blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr_t count, daddr_t radix,
}
skip = radix_to_skip(radix);
next_skip = skip / BLIST_META_RADIX;
blk = allocBlk & -radix;
/*
* An ALL-FREE meta node requires special handling before allocating
@ -814,7 +814,7 @@ blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr_t count, daddr_t radix,
v = blk + radix - allocBlk;
if (v > count)
v = count;
nblks += blst_meta_fill(&scan[i], allocBlk, v, radix, blk);
nblks += blst_meta_fill(&scan[i], allocBlk, v, radix);
count -= v;
allocBlk += v;
blk += radix;

2
sys/sys/blist.h
View File

@ -80,7 +80,7 @@ typedef struct blmeta {
typedef struct blist {
daddr_t bl_blocks; /* area of coverage */
daddr_t bl_radix; /* coverage radix */
u_daddr_t bl_radix; /* coverage radix */
daddr_t bl_cursor; /* next-fit search starts at */
blmeta_t *bl_root; /* root of radix tree */
} *blist_t;