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Stop checking TD_IDLETHREAD() in buffer cache routines.

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These predicates are vestigal and cannot be true today.  For example,
idle threads are not allowed to acquire locks.

Also cache curthread in breada().

No functional change intended.

Reviewed by:	kib, mckusick
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D20066
This commit is contained in:
Mark Johnston 2019-04-29 13:23:32 +00:00
parent 761618de05
commit 8e7130a8a7
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=346888
1 changed files with 21 additions and 27 deletions
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48
sys/kern/vfs_bio.c
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@ -2073,8 +2073,11 @@ breada(struct vnode * vp, daddr_t * rablkno, int * rabsize, int cnt,
struct ucred * cred, int flags, void (*ckhashfunc)(struct buf *))
{
struct buf *rabp;
struct thread *td;
int i;
td = curthread;
for (i = 0; i < cnt; i++, rablkno++, rabsize++) {
if (inmem(vp, *rablkno))
continue;
@ -2083,16 +2086,14 @@ breada(struct vnode * vp, daddr_t * rablkno, int * rabsize, int cnt,
brelse(rabp);
continue;
}
if (!TD_IS_IDLETHREAD(curthread)) {
#ifdef RACCT
if (racct_enable) {
PROC_LOCK(curproc);
racct_add_buf(curproc, rabp, 0);
PROC_UNLOCK(curproc);
}
#endif /* RACCT */
curthread->td_ru.ru_inblock++;
if (racct_enable) {
PROC_LOCK(curproc);
racct_add_buf(curproc, rabp, 0);
PROC_UNLOCK(curproc);
}
#endif /* RACCT */
td->td_ru.ru_inblock++;
rabp->b_flags |= B_ASYNC;
rabp->b_flags &= ~B_INVAL;
if ((flags & GB_CKHASH) != 0) {
@ -2148,16 +2149,14 @@ breadn_flags(struct vnode *vp, daddr_t blkno, int size, daddr_t *rablkno,
*/
readwait = 0;
if ((bp->b_flags & B_CACHE) == 0) {
if (!TD_IS_IDLETHREAD(td)) {
#ifdef RACCT
if (racct_enable) {
PROC_LOCK(td->td_proc);
racct_add_buf(td->td_proc, bp, 0);
PROC_UNLOCK(td->td_proc);
}
#endif /* RACCT */
td->td_ru.ru_inblock++;
if (racct_enable) {
PROC_LOCK(td->td_proc);
racct_add_buf(td->td_proc, bp, 0);
PROC_UNLOCK(td->td_proc);
}
#endif /* RACCT */
td->td_ru.ru_inblock++;
bp->b_iocmd = BIO_READ;
bp->b_flags &= ~B_INVAL;
if ((flags & GB_CKHASH) != 0) {
@ -2258,16 +2257,14 @@ bufwrite(struct buf *bp)
bp->b_runningbufspace = bp->b_bufsize;
space = atomic_fetchadd_long(&runningbufspace, bp->b_runningbufspace);
if (!TD_IS_IDLETHREAD(curthread)) {
#ifdef RACCT
if (racct_enable) {
PROC_LOCK(curproc);
racct_add_buf(curproc, bp, 1);
PROC_UNLOCK(curproc);
}
#endif /* RACCT */
curthread->td_ru.ru_oublock++;
if (racct_enable) {
PROC_LOCK(curproc);
racct_add_buf(curproc, bp, 1);
PROC_UNLOCK(curproc);
}
#endif /* RACCT */
curthread->td_ru.ru_oublock++;
if (oldflags & B_ASYNC)
BUF_KERNPROC(bp);
bp->b_iooffset = dbtob(bp->b_blkno);
@ -4019,9 +4016,6 @@ getblkx(struct vnode *vp, daddr_t blkno, int size, int slpflag, int slptimeo,
*/
if (flags & GB_NOCREAT)
return (EEXIST);
if (bdomain[bo->bo_domain].bd_freebuffers == 0 &&
TD_IS_IDLETHREAD(curthread))
return (EBUSY);
bsize = vn_isdisk(vp, NULL) ? DEV_BSIZE : bo->bo_bsize;
KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize"));