on entry and it assumes the responsibility for releasing the page queues
lock if it must sleep.
Remove a bogus comment from pmap_enter_quick().
Using the first change, modify vm_map_pmap_enter() so that the page queues
lock is acquired and released once, rather than each time that a page
is mapped.
In such cases, the busying of the page and the unlocking of the
containing object by vm_map_pmap_enter() and vm_fault_prefault() is
unnecessary overhead. To eliminate this overhead, this change
modifies pmap_enter_quick() so that it expects the object to be locked
on entry and it assumes the responsibility for busying the page and
unlocking the object if it must sleep. Note: alpha, amd64, i386 and
ia64 are the only implementations optimized by this change; arm,
powerpc, and sparc64 still conservatively busy the page and unlock the
object within every pmap_enter_quick() call.
Additionally, this change is the first case where we synchronize
access to the page's PG_BUSY flag and busy field using the containing
object's lock rather than the global page queues lock. (Modifications
to the page's PG_BUSY flag and busy field have asserted both locks for
several weeks, enabling an incremental transition.)
specified register, but a pointer to the in-memory representation of
that value. The reason for this is twofold:
1. Not all registers can be represented by a register_t. In particular
FP registers fall in that category. Passing the new register value
by reference instead of by value makes this point moot.
2. When we receive a G or P packet, both are for writing a register,
the packet will have the register value in target-byte order and
in the memory representation (modulo the fact that bytes are sent
as 2 printable hexadecimal numbers of course). We only need to
decode the packet to have a pointer to the register value.
This change fixes the bug of extracting the register value of the P
packet as a hexadecimal number instead of as a bit array. The quick
(and dirty) fix to bswap the register value in gdb_cpu_setreg() as
it has been added on i386 and amd64 can therefore be removed and has
in fact been that.
Tested on: alpha, amd64, i386, ia64, sparc64
Allocate the bounce zone at either tag creation or map creation to help
avoid null-pointer derefs later on. Track total pages per zone so that
each zone can get a minimum allocation at tag creation time instead of
being defeated by mis-behaving tags that suck up the max amount.
control the number of lines per page rather than a constant. The variable
can be examined and changed in ddb as '$lines'. Setting the variable to
0 will effectively turn off paging.
- Change db_putchar() to force out pending whitespace before outputting
newlines and carriage returns so that one can rub out content on the
current line via '\r \r' type strings.
- Change the simple pager to rub out the --More-- prompt explicitly when
the routine exits.
- Add some aliases to the simple pager to make it more compatible with
more(1): 'e' and 'j' do a single line. 'd' does half a page, and
'f' does a full page.
MFC after: 1 month
Inspired by: kris
that was greater than 4G. I originally used the same values as i386 in
order to save opening a new PML4 page slot, but in the day of gigabytes
of memory, worrying about a 4K page seems futile. Moving from 8 to 32G
moves the page to a different index, it doesn't increase the number of
pages used.
Restructure pmap_enter() to prevent the loss of a page modified (PG_M) bit
in a race between processors. (This restructuring assumes the newly atomic
pte_load_store() for correct operation.)
Reviewed by: tegge@
PR: i386/61852
the raw values including for child process statistics and only compute the
system and user timevals on demand.
- Fix the various kern_wait() syscall wrappers to only pass in a rusage
pointer if they are going to use the result.
- Add a kern_getrusage() function for the ABI syscalls to use so that they
don't have to play stackgap games to call getrusage().
- Fix the svr4_sys_times() syscall to just call calcru() to calculate the
times it needs rather than calling getrusage() twice with associated
stackgap, etc.
- Add a new rusage_ext structure to store raw time stats such as tick counts
for user, system, and interrupt time as well as a bintime of the total
runtime. A new p_rux field in struct proc replaces the same inline fields
from struct proc (i.e. p_[isu]ticks, p_[isu]u, and p_runtime). A new p_crux
field in struct proc contains the "raw" child time usage statistics.
ruadd() has been changed to handle adding the associated rusage_ext
structures as well as the values in rusage. Effectively, the values in
rusage_ext replace the ru_utime and ru_stime values in struct rusage. These
two fields in struct rusage are no longer used in the kernel.
- calcru() has been split into a static worker function calcru1() that
calculates appropriate timevals for user and system time as well as updating
the rux_[isu]u fields of a passed in rusage_ext structure. calcru() uses a
copy of the process' p_rux structure to compute the timevals after updating
the runtime appropriately if any of the threads in that process are
currently executing. It also now only locks sched_lock internally while
doing the rux_runtime fixup. calcru() now only requires the caller to
hold the proc lock and calcru1() only requires the proc lock internally.
calcru() also no longer allows callers to ask for an interrupt timeval
since none of them actually did.
- calcru() now correctly handles threads executing on other CPUs.
- A new calccru() function computes the child system and user timevals by
calling calcru1() on p_crux. Note that this means that any code that wants
child times must now call this function rather than reading from p_cru
directly. This function also requires the proc lock.
- This finishes the locking for rusage and friends so some of the Giant locks
in exit1() and kern_wait() are now gone.
- The locking in ttyinfo() has been tweaked so that a shared lock of the
proctree lock is used to protect the process group rather than the process
group lock. By holding this lock until the end of the function we now
ensure that the process/thread that we pick to dump info about will no
longer vanish while we are trying to output its info to the console.
Submitted by: bde (mostly)
MFC after: 1 month
that is no longer required. (In fact, it is not clear that it was ever
required in HEAD or RELENG_4, only RELENG_3 required a work-around.) Now,
as before revision 1.251, if the preexisting PTE is invalid, pmap_enter()
does not call pmap_invalidate_page() to update the TLB(s).
Note: Even with this change, the handling of a copy-on-write fault is
inefficient, in such cases pmap_enter() calls pmap_invalidate_page() twice.
Discussed with: bde@
PR: kern/16568
need to mask off the page offset bits. (This operation made some sense
prior to i386/i386/pmap.c revision 1.254 when we passed a physical address
rather than a vm_page pointer to pmap_enter().)
uses predate the change in the pmap_enter() interface that replaced the
page's physical address by the address of its vm_page structure. The
PHYS_TO_VM_PAGE() was being used to compute the address of the same vm_page
structure that was being passed in.
pmap_copy(). This entails additional locking in pmap_copy() and the
addition of a "flags" parameter to the page table page allocator for
specifying whether it may sleep when memory is unavailable. (Already,
pmap_copy() checks the availability of memory, aborting if it is scarce.
In theory, another CPU could, however, allocate memory between
pmap_copy()'s check and the call to the page table page allocator,
causing the current thread to release its locks and sleep. This change
makes this scenario impossible.)
Reviewed by: tegge@
because it was mostly irrelevant - except for the silly BIOS_PADDRTOVADDR
etc macros. Along the way of working around this, I missed a few things.
* Make syscons properly inherit the bios capslock/shiftlock/etc state like
i386 does. Note that we cannot inherit the bios key repeat rate because
that requires a bios call (which is impossible for us).
* Give syscons the ability to beep on amd64. Oops.
While here, make bios.c compile and add it to files.amd64.
multiprocessors. Specifically, the error is conditioning the call to
pmap_invalidate_page() on whether the pmap is active on the current CPU.
This call must be unconditional. Regardless of whether the pmap is active
on the CPU performing _pmap_unwire_pte_hold(), it could be active on another
CPU. For example, a call to pmap_remove_all() by the page daemon could
result in a call to _pmap_unwire_pte_hold() with the pmap inactive on the
current CPU and active on another CPU. In such circumstances, failing to
call pmap_invalidate_page() results in a stale TLB entry on the other CPU
that still maps the now deallocated page table page. What happens next is
typically a mysterious panic in pmap_enter() by the other CPU, either
"pmap_enter: attempted pmap_enter on 4MB page" or "pmap_enter: pte vanished,
va: 0x%lx". Both occur because the former page table page has been recycled
and allocated to a new purpose. Consequently, it no longer contains zeroes.
See also Peter's i386/i386/pmap.c revision 1.448 and the related e-mail
thread last year.
Many thanks to the engineers at Sandvine for providing clear and concise
information until all of the pieces of the puzzle fell into place and
for testing an earlier patch.
MT5 Candidate
