Commit Graph

9 Commits

Author SHA1 Message Date
Gerd Hoffmann 9a0b5817ad [PATCH] x86: SMP alternatives
Implement SMP alternatives, i.e.  switching at runtime between different
code versions for UP and SMP.  The code can patch both SMP->UP and UP->SMP.
The UP->SMP case is useful for CPU hotplug.

With CONFIG_CPU_HOTPLUG enabled the code switches to UP at boot time and
when the number of CPUs goes down to 1, and switches to SMP when the number
of CPUs goes up to 2.

Without CONFIG_CPU_HOTPLUG or on non-SMP-capable systems the code is
patched once at boot time (if needed) and the tables are released
afterwards.

The changes in detail:

  * The current alternatives bits are moved to a separate file,
    the SMP alternatives code is added there.

  * The patch adds some new elf sections to the kernel:
    .smp_altinstructions
	like .altinstructions, also contains a list
	of alt_instr structs.
    .smp_altinstr_replacement
	like .altinstr_replacement, but also has some space to
	save original instruction before replaving it.
    .smp_locks
	list of pointers to lock prefixes which can be nop'ed
	out on UP.
    The first two are used to replace more complex instruction
    sequences such as spinlocks and semaphores.  It would be possible
    to deal with the lock prefixes with that as well, but by handling
    them as special case the table sizes become much smaller.

 * The sections are page-aligned and padded up to page size, so they
   can be free if they are not needed.

 * Splitted the code to release init pages to a separate function and
   use it to release the elf sections if they are unused.

Signed-off-by: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-23 07:38:04 -08:00
Ingo Molnar 652050aec9 [PATCH] mark several functions __always_inline
Arjan van de Ven <arjan@infradead.org>

Mark a number of functions as 'must inline'.  The functions affected by this
patch need to be inlined because they use knowledge that their arguments are
constant so that most of the function optimizes away.  At this point this
patch does not change behavior, it's for documentation only (and for future
patches in the inline series)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-14 18:27:15 -08:00
Andi Kleen 92934bcbf9 [PATCH] i386/x86-64: Use input/output dependencies for bitops
Noticed by Andreas Schwab

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-11 19:01:11 -08:00
Stephen Hemminger d832245d7c [PATCH] x86: fls() in asm
There is a single instruction on i386 to find largest set bit; so it makes
sense to use it (like we use bfs for ffs()).

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:38 -08:00
David Howells d89c145c03 [PATCH] x86: handle -Wsign-compare in bitops
Make i386's find_first_bit() use an unsigned integer as a counter to avoid
getting warnings when -Wsign-compare is given.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:36 -08:00
Stephen Hemminger 3821af2fe1 [FLS64]: generic version
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:11:06 -08:00
Linus Torvalds d6d2a2ab05 x86: fix new find_first_bit()
Some edge problems with the original C rewrite.

Thanks go to Cal Peake, who pinpointed the breakage to the rewrite, and
tested this fixed version.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-29 11:01:22 -04:00
Steven Rostedt cd85c8b445 [PATCH] speed up on find_first_bit for i386 (let compiler do the work)
Avoid using "rep scas", just let the compiler select a sequence of
regular instructions.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-28 08:40:31 -07:00
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00