Commit Graph

271 Commits

Author SHA1 Message Date
Hugh Dickins 7c1fd6b964 [PATCH] mm: exit_mmap need not reset
exit_mmap resets various mm_struct fields, but the mm is well on its way out,
and none of those fields matter by this point.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:37 -07:00
Hugh Dickins a8fb5618da [PATCH] mm: unlink_file_vma, remove_vma
Divide remove_vm_struct into two parts: first anon_vma_unlink plus
unlink_file_vma, to unlink the vma from the list and tree by which rmap or
vmtruncate might find it; then remove_vma to close, fput and free.

The intention here is to do the anon_vma_unlink and unlink_file_vma earlier,
in free_pgtables before freeing any page tables: so we can be sure that any
page tables traversed by rmap and vmtruncate are stable (and other, ordinary
cases are stabilized by holding mmap_sem).

This will be crucial to traversing pgd,pud,pmd without page_table_lock.  But
testing the split-out patch showed that lifting the page_table_lock is
symbiotically necessary to make this change - the lock ordering is wrong to
move those unlinks into free_pgtables while it's under ptlock.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:37 -07:00
Hugh Dickins 2c0b381467 [PATCH] mm: remove_vma_list consolidation
unmap_vma doesn't amount to much, let's put it inside unmap_vma_list.  Except
it doesn't unmap anything, unmap_region just did the unmapping: rename it to
remove_vma_list.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:37 -07:00
Hugh Dickins ab50b8ed81 [PATCH] mm: vm_stat_account unshackled
The original vm_stat_account has fallen into disuse, with only one user, and
only one user of vm_stat_unaccount.  It's easier to keep track if we convert
them all to __vm_stat_account, then free it from its __shackles.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:37 -07:00
Paolo 'Blaisorblade' Giarrusso f10df68604 [PATCH] fix locking comment in unmap_region()
That comment is plain wrong (we even take the pagetable lock inside
unmap_region()).

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-21 10:11:55 -07:00
Hugh Dickins 2fd4ef85e0 [PATCH] error path in setup_arg_pages() misses vm_unacct_memory()
Pavel Emelianov and Kirill Korotaev observe that fs and arch users of
security_vm_enough_memory tend to forget to vm_unacct_memory when a
failure occurs further down (typically in setup_arg_pages variants).

These are all users of insert_vm_struct, and that reservation will only
be unaccounted on exit if the vma is marked VM_ACCOUNT: which in some
cases it is (hidden inside VM_STACK_FLAGS) and in some cases it isn't.

So x86_64 32-bit and ppc64 vDSO ELFs have been leaking memory into
Committed_AS each time they're run.  But don't add VM_ACCOUNT to them,
it's inappropriate to reserve against the very unlikely case that gdb
be used to COW a vDSO page - we ought to do something about that in
do_wp_page, but there are yet other inconsistencies to be resolved.

The safe and economical way to fix this is to let insert_vm_struct do
the security_vm_enough_memory check when it finds VM_ACCOUNT is set.

And the MIPS irix_brk has been calling security_vm_enough_memory before
calling do_brk which repeats it, doubly accounting and so also leaking.
Remove that, and all the fs and arch calls to security_vm_enough_memory:
give it a less misleading name later on.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-Off-By: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-14 11:18:13 -07:00
Christoph Hellwig cdb3826b99 [PATCH] remove misleading comment above sys_brk
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07 16:57:23 -07:00
Christoph Lameter c3d8c14145 [PATCH] More __read_mostly variables
Move some more frequently read variables that showed up during some of our
performance tests as sometimes ending up in hot cachelines to the
read_mostly section.

Fix: Move the __read_mostly from before hpet_usec_quotient to follow the
variable like the other uses of __read_mostly.

Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Christoph Lameter <christoph@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07 16:57:18 -07:00
Simon Derr 2f60f8d357 [PATCH] __vm_enough_memory() signedness fix
We have found what seems to be a small bug in __vm_enough_memory() when
sysctl_overcommit_memory is set to OVERCOMMIT_NEVER.

When this bug occurs the systems fails to boot, with /sbin/init whining
about fork() returning ENOMEM.

We hunted down the problem to this:

The deferred update mecanism used in vm_acct_memory(), on a SMP system,
allows the vm_committed_space counter to have a negative value.

This should not be a problem since this counter is known to be inaccurate.

But in __vm_enough_memory() this counter is compared to the `allowed'
variable, which is an unsigned long.  This comparison is broken since it
will consider the negative values of vm_committed_space to be huge positive
values, resulting in a memory allocation failure.

Signed-off-by: <Jean-Marc.Saffroy@ext.bull.net>
Signed-off-by: <Simon.Derr@bull.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-04 21:43:14 -07:00
Chris Wright 73219d1780 [PATCH] mmap topdown fix for large stack limit, large allocation
The topdown changes in 2.6.12-rc1 can cause large allocations with large
stack limit to fail, despite there being space available.  The
mmap_base-len is only valid when len >= mmap_base.  However, nothing in
topdown allocator checks this.  It's only (now) caught at higher level,
which will cause allocation to simply fail.  The following change restores
the fallback to bottom-up path, which will allow large allocations with
large stack limit to potentially still succeed.

Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-21 18:46:16 -07:00
Wolfgang Wander 1363c3cd86 [PATCH] Avoiding mmap fragmentation
Ingo recently introduced a great speedup for allocating new mmaps using the
free_area_cache pointer which boosts the specweb SSL benchmark by 4-5% and
causes huge performance increases in thread creation.

The downside of this patch is that it does lead to fragmentation in the
mmap-ed areas (visible via /proc/self/maps), such that some applications
that work fine under 2.4 kernels quickly run out of memory on any 2.6
kernel.

The problem is twofold:

  1) the free_area_cache is used to continue a search for memory where
     the last search ended.  Before the change new areas were always
     searched from the base address on.

     So now new small areas are cluttering holes of all sizes
     throughout the whole mmap-able region whereas before small holes
     tended to close holes near the base leaving holes far from the base
     large and available for larger requests.

  2) the free_area_cache also is set to the location of the last
     munmap-ed area so in scenarios where we allocate e.g.  five regions of
     1K each, then free regions 4 2 3 in this order the next request for 1K
     will be placed in the position of the old region 3, whereas before we
     appended it to the still active region 1, placing it at the location
     of the old region 2.  Before we had 1 free region of 2K, now we only
     get two free regions of 1K -> fragmentation.

The patch addresses thes issues by introducing yet another cache descriptor
cached_hole_size that contains the largest known hole size below the
current free_area_cache.  If a new request comes in the size is compared
against the cached_hole_size and if the request can be filled with a hole
below free_area_cache the search is started from the base instead.

The results look promising: Whereas 2.6.12-rc4 fragments quickly and my
(earlier posted) leakme.c test program terminates after 50000+ iterations
with 96 distinct and fragmented maps in /proc/self/maps it performs nicely
(as expected) with thread creation, Ingo's test_str02 with 20000 threads
requires 0.7s system time.

Taking out Ingo's patch (un-patch available per request) by basically
deleting all mentions of free_area_cache from the kernel and starting the
search for new memory always at the respective bases we observe: leakme
terminates successfully with 11 distinctive hardly fragmented areas in
/proc/self/maps but thread creating is gringdingly slow: 30+s(!) system
time for Ingo's test_str02 with 20000 threads.

Now - drumroll ;-) the appended patch works fine with leakme: it ends with
only 7 distinct areas in /proc/self/maps and also thread creation seems
sufficiently fast with 0.71s for 20000 threads.

Signed-off-by: Wolfgang Wander <wwc@rentec.com>
Credit-to: "Richard Purdie" <rpurdie@rpsys.net>
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu> (partly)
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-21 18:46:16 -07:00
Linus Torvalds 07ab67c8d0 Fix get_unmapped_area sanity tests
As noted by Chris Wright, we need to do the full range of tests regardless
of whether MAP_FIXED is set or not, so re-organize get_unmapped_area()
slightly to do the sanity checks unconditionally.
2005-05-19 22:43:37 -07:00
Linus Torvalds 49a43876b9 [PATCH] prevent NULL mmap in topdown model
Prevent the topdown allocator from allocating mmap areas all the way
down to address zero.

We still allow a MAP_FIXED mapping of page 0 (needed for various things,
ranging from Wine and DOSEMU to people who want to allow speculative
loads off a NULL pointer).

Tested by Chris Wright.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-19 07:46:36 -07:00
Chris Wright 93ea1d0a12 [PATCH] RLIMIT_MEMLOCK checking fix
Always use page counts when doing RLIMIT_MEMLOCK checking to avoid possible
overflow.

Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 08:58:38 -07:00
akpm@osdl.org 119f657c72 [PATCH] RLIMIT_AS checking fix
Address bug #4508: there's potential for wraparound in the various places
where we perform RLIMIT_AS checking.

(I'm a bit worried about acct_stack_growth().  Are we sure that vma->vm_mm is
always equal to current->mm?  If not, then we're comparing some other
process's total_vm with the calling process's rlimits).

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 08:58:35 -07:00
Hugh Dickins 561bbe3235 [PATCH] freepgt: remove FIRST_USER_ADDRESS hack
Once all the MMU architectures define FIRST_USER_ADDRESS, remove hack from
mmap.c which derived it from FIRST_USER_PGD_NR.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-19 13:29:23 -07:00
Hugh Dickins e2cdef8c84 [PATCH] freepgt: free_pgtables from FIRST_USER_ADDRESS
The patches to free_pgtables by vma left problems on any architectures which
leave some user address page table entries unencapsulated by vma.  Andi has
fixed the 32-bit vDSO on x86_64 to use a vma.  Now fix arm (and arm26), whose
first PAGE_SIZE is reserved (perhaps) for machine vectors.

Our calls to free_pgtables must not touch that area, and exit_mmap's
BUG_ON(nr_ptes) must allow that arm's get_pgd_slow may (or may not) have
allocated an extra page table, which its free_pgd_slow would free later.

FIRST_USER_PGD_NR has misled me and others: until all the arches define
FIRST_USER_ADDRESS instead, a hack in mmap.c to derive one from t'other.  This
patch fixes the bugs, the remaining patches just clean it up.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-19 13:29:19 -07:00
Hugh Dickins 146425a316 [PATCH] freepgt: mpnt to vma cleanup
While dabbling here in mmap.c, clean up mysterious "mpnt"s to "vma"s.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-19 13:29:18 -07:00
Hugh Dickins ee39b37b23 [PATCH] freepgt: remove MM_VM_SIZE(mm)
There's only one usage of MM_VM_SIZE(mm) left, and it's a troublesome macro
because mm doesn't contain the (32-bit emulation?) info needed.  But it too is
only needed because we ignore the end from the vma list.

We could make flush_pgtables return that end, or unmap_vmas.  Choose the
latter, since it's a natural fit with unmap_mapping_range_vma needing to know
its restart addr.  This does make more than minimal change, but if unmap_vmas
had returned the end before, this is how we'd have done it, rather than
storing the break_addr in zap_details.

unmap_vmas used to return count of vmas scanned, but that's just debug which
hasn't been useful in a while; and if we want the map_count 0 on exit check
back, it can easily come from the final remove_vm_struct loop.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-19 13:29:15 -07:00
Hugh Dickins e0da382c92 [PATCH] freepgt: free_pgtables use vma list
Recent woes with some arches needing their own pgd_addr_end macro; and 4-level
clear_page_range regression since 2.6.10's clear_page_tables; and its
long-standing well-known inefficiency in searching throughout the higher-level
page tables for those few entries to clear and free: all can be blamed on
ignoring the list of vmas when we free page tables.

Replace exit_mmap's clear_page_range of the total user address space by
free_pgtables operating on the mm's vma list; unmap_region use it in the same
way, giving floor and ceiling beyond which it may not free tables.  This
brings lmbench fork/exec/sh numbers back to 2.6.10 (unless preempt is enabled,
in which case latency fixes spoil unmap_vmas throughput).

Beware: the do_mmap_pgoff driver failure case must now use unmap_region
instead of zap_page_range, since a page table might have been allocated, and
can only be freed while it is touched by some vma.

Move free_pgtables from mmap.c to memory.c, where its lower levels are adapted
from the clear_page_range levels.  (Most of free_pgtables' old code was
actually for a non-existent case, prev not properly set up, dating from before
hch gave us split_vma.) Pass mmu_gather** in the public interfaces, since we
might want to add latency lockdrops later; but no attempt to do so yet, going
by vma should itself reduce latency.

But what if is_hugepage_only_range?  Those ia64 and ppc64 cases need careful
examination: put that off until a later patch of the series.

What of x86_64's 32bit vdso page __map_syscall32 maps outside any vma?

And the range to sparc64's flush_tlb_pgtables?  It's less clear to me now that
we need to do more than is done here - every PMD_SIZE ever occupied will be
flushed, do we really have to flush every PGDIR_SIZE ever partially occupied? 
A shame to complicate it unnecessarily.

Special thanks to David Miller for time spent repairing my ceilings.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-19 13:29:15 -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