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Touch all the pages wired by sysctl_wire_old_buffer() to avoid PTE

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modified bit emulation traps on Alpha while holding locks in the
sysctl handler.

A better solution would be to pass a hint to the Alpha pmap code to
tell mark these pages as modified when they as they are being wired,
but that appears to be more difficult to implement.

Suggested by: jhb
MFC after:	3 days
This commit is contained in:
truckman 2006-01-25 01:03:34 +00:00
parent 4730881b84
commit 9f8a407ccb
1 changed files with 12 additions and 1 deletions
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13
sys/kern/kern_sysctl.c
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@ -1118,7 +1118,8 @@ int
sysctl_wire_old_buffer(struct sysctl_req *req, size_t len)
{
int ret;
size_t wiredlen;
size_t i, wiredlen;
char *cp, dummy;
wiredlen = (len > 0 && len < req->oldlen) ? len : req->oldlen;
ret = 0;
@ -1131,6 +1132,16 @@ sysctl_wire_old_buffer(struct sysctl_req *req, size_t len)
return (ret);
wiredlen = 0;
}
/*
* Touch all the wired pages to avoid PTE modified
* bit emulation traps on Alpha while holding locks
* in the sysctl handler.
*/
for (i = (wiredlen + PAGE_SIZE - 1) / PAGE_SIZE,
cp = req->oldptr; i > 0; i--, cp += PAGE_SIZE) {
copyin(cp, &dummy, 1);
copyout(&dummy, cp, 1);
}
}
req->lock = REQ_WIRED;
req->validlen = wiredlen;