linux.git/mm/mempool.c, branch v2.6.12 Linux kernel source tree [PATCH] use smp_mb/wmb/rmb where possible 2005-05-01T15:58:47+00:00 akpm@osdl.org akpm@osdl.org 2005-05-01T15:58:47+00:00 d59dd4620fb8d6422555a9e2b82a707718e68327 Replace a number of memory barriers with smp_ variants. This means we won't take the unnecessary hit on UP machines. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> 
Replace a number of memory barriers with smp_ variants.  This means we won't
take the unnecessary hit on UP machines.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] mempool: simplify alloc 2005-05-01T15:58:37+00:00 Nick Piggin nickpiggin@yahoo.com.au 2005-05-01T15:58:37+00:00 20a77776c24800d1e40a73f520cfcb32239568a9 Mempool is pretty clever. Looks too clever for its own good :) It shouldn't really know so much about page reclaim internals. - don't guess about what effective page reclaim might involve. - don't randomly flush out all dirty data if some unlikely thing happens (alloc returns NULL). page reclaim can (sort of :P) handle it. I think the main motivation is trying to avoid pool->lock at all costs. However the first allocation is attempted with __GFP_WAIT cleared, so it will be 'can_try_harder' if it hits the page allocator. So if allocation still fails, then we can probably afford to hit the pool->lock - and what's the alternative? Try page reclaim and hit zone->lru_lock? A nice upshot is that we don't need to do any fancy memory barriers or do (intentionally) racy access to pool-> fields outside the lock. Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> 
Mempool is pretty clever.  Looks too clever for its own good :) It
shouldn't really know so much about page reclaim internals.

- don't guess about what effective page reclaim might involve.

- don't randomly flush out all dirty data if some unlikely thing
  happens (alloc returns NULL). page reclaim can (sort of :P) handle
  it.

I think the main motivation is trying to avoid pool->lock at all costs.
However the first allocation is attempted with __GFP_WAIT cleared, so it
will be 'can_try_harder' if it hits the page allocator.  So if allocation
still fails, then we can probably afford to hit the pool->lock - and what's
the alternative?  Try page reclaim and hit zone->lru_lock?

A nice upshot is that we don't need to do any fancy memory barriers or do
(intentionally) racy access to pool-> fields outside the lock.

Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] mempool: NOMEMALLOC and NORETRY 2005-05-01T15:58:36+00:00 Nick Piggin nickpiggin@yahoo.com.au 2005-05-01T15:58:36+00:00 b84a35be0285229b0a8a5e2e04d79360c5b75562 Mempools have 2 problems. The first is that mempool_alloc can possibly get stuck in __alloc_pages when they should opt to fail, and take an element from their reserved pool. The second is that it will happily eat emergency PF_MEMALLOC reserves instead of going to their reserved pools. Fix the first by passing __GFP_NORETRY in the allocation calls in mempool_alloc. Fix the second by introducing a __GFP_MEMPOOL flag which directs the page allocator not to allocate from the reserve pool. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> 
Mempools have 2 problems.

The first is that mempool_alloc can possibly get stuck in __alloc_pages
when they should opt to fail, and take an element from their reserved pool.

The second is that it will happily eat emergency PF_MEMALLOC reserves
instead of going to their reserved pools.

Fix the first by passing __GFP_NORETRY in the allocation calls in
mempool_alloc.  Fix the second by introducing a __GFP_MEMPOOL flag which
directs the page allocator not to allocate from the reserve pool.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Linux-2.6.12-rc2 2005-04-16T22:20:36+00:00 Linus Torvalds torvalds@ppc970.osdl.org 2005-04-16T22:20:36+00:00 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 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! 
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!