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Code Issues Releases Activity

Provide an alternative mbuf cluster allocator which permits use of

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clusters greater than one page in length by calling contigmalloc1().
This uses a helper process `mclalloc' to do the allocation if
the system runs out at interrupt time to avoid calling contigmalloc
at high spl.  It is not yet clear to me whether this works.
This commit is contained in:
Garrett Wollman 1997-02-13 19:41:40 +00:00
parent 10825343b0
commit 30f700e9c7
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=22671
1 changed files with 46 additions and 1 deletions
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47
sys/kern/uipc_mbuf.c
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@ -81,8 +81,14 @@ mbinit(dummy)
s = splimp();
if (m_mballoc(NMB_INIT, M_DONTWAIT) == 0)
goto bad;
#if MCLBYTES <= PAGE_SIZE
if (m_clalloc(NCL_INIT, M_DONTWAIT) == 0)
goto bad;
#else
/* It's OK to call contigmalloc in this context. */
if (m_clalloc(16, 0) == 0)
goto bad;
#endif
splx(s);
return;
bad:
@ -130,6 +136,34 @@ m_mballoc(nmb, nowait)
return (1);
}
#if MCLBYTES > PAGE_SIZE
int i_want_my_mcl;
void
kproc_mclalloc(void)
{
int status;
while (1) {
tsleep(&i_want_my_mcl, PVM, "mclalloc", 0);
for (; i_want_my_mcl; i_want_my_mcl--) {
if (m_clalloc(1, 0) == 0)
printf("m_clalloc failed even in process context!\n");
}
}
}
static struct proc *mclallocproc;
static struct kproc_desc mclalloc_kp = {
"mclalloc",
kproc_mclalloc,
&mclallocproc
};
SYSINIT_KT(mclallocproc, SI_SUB_KTHREAD_UPDATE, SI_ORDER_ANY, kproc_start,
&mclalloc_kp);
#endif
/*
* Allocate some number of mbuf clusters
* and place on cluster free list.
@ -153,9 +187,21 @@ m_clalloc(ncl, nowait)
if (mb_map_full)
return (0);
#if MCLBYTES > PAGE_SIZE
if (nowait) {
i_want_my_mcl += ncl;
wakeup(&i_want_my_mcl);
p = 0;
} else {
p = contigmalloc1(MCLBYTES * ncl, M_DEVBUF, M_WAITOK, 0ul,
~0ul, PAGE_SIZE, 0, mb_map);
}
#else
npg = ncl;
p = (caddr_t)kmem_malloc(mb_map, ctob(npg),
nowait ? M_NOWAIT : M_WAITOK);
ncl = ncl * PAGE_SIZE / MCLBYTES;
#endif
/*
* Either the map is now full, or this is nowait and there
* are no pages left.
@ -163,7 +209,6 @@ m_clalloc(ncl, nowait)
if (p == NULL)
return (0);
ncl = ncl * PAGE_SIZE / MCLBYTES;
for (i = 0; i < ncl; i++) {
((union mcluster *)p)->mcl_next = mclfree;
mclfree = (union mcluster *)p;