svn commit: r324130 - in stable/11/sys: kern sys
Alan Cox
alc at FreeBSD.org
Sat Sep 30 19:23:50 UTC 2017
Author: alc
Date: Sat Sep 30 19:23:49 2017
New Revision: 324130
URL: https://svnweb.freebsd.org/changeset/base/324130
Log:
MFC r322459,322897
The *_meta_* functions include a radix parameter, a blk parameter, and
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.)
Correct a regression in the previous change, r322459. Specifically, the
removal of the "blk" parameter from blst_meta_alloc() had the unintended
effect of generating an out-of-range allocation when the cursor reaches
the end of the tree if the number of managed blocks in the tree equals
the so-called "radix" (which in the blist code is not the standard notion
of what a radix is but rather the maximum number of leaves in a tree of
the current height.) In other words, only certain swap configurations
were affected, which is why earlier testing did not reveal the problem.
Modified:
stable/11/sys/kern/subr_blist.c
stable/11/sys/sys/blist.h
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/kern/subr_blist.c
==============================================================================
--- stable/11/sys/kern/subr_blist.c Sat Sep 30 18:52:59 2017 (r324129)
+++ stable/11/sys/kern/subr_blist.c Sat Sep 30 19:23:49 2017 (r324130)
@@ -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,
@@ -247,10 +247,12 @@ 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;
+ if (bl->bl_cursor == bl->bl_blocks)
+ bl->bl_cursor = 0;
return (blk);
} else if (bl->bl_cursor != 0)
bl->bl_cursor = 0;
@@ -280,7 +282,7 @@ 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 +295,7 @@ 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 +449,13 @@ blst_leaf_alloc(blmeta_t *scan, daddr_t blk, int count
* 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 +507,8 @@ blst_meta_alloc(blmeta_t *scan, daddr_t blk, daddr_t c
/*
* 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 +576,9 @@ 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 +629,7 @@ blst_meta_free(blmeta_t *scan, daddr_t freeBlk, daddr_
* Break the free down into its components
*/
+ blk = freeBlk & -radix;
radix /= BLIST_META_RADIX;
child = (freeBlk - blk) / radix;
@@ -637,7 +639,7 @@ blst_meta_free(blmeta_t *scan, daddr_t freeBlk, daddr_
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 +757,9 @@ 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 +784,7 @@ blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr
}
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 +816,7 @@ blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr
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;
Modified: stable/11/sys/sys/blist.h
==============================================================================
--- stable/11/sys/sys/blist.h Sat Sep 30 18:52:59 2017 (r324129)
+++ stable/11/sys/sys/blist.h Sat Sep 30 19:23:49 2017 (r324130)
@@ -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;
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