22 Mar, 2006
40 commits
-
Centralize the page migration functions in anticipation of additional
tinkering. Creates a new file mm/migrate.c1. Extract buffer_migrate_page() from fs/buffer.c
2. Extract central migration code from vmscan.c
3. Extract some components from mempolicy.c
4. Export pageout() and remove_from_swap() from vmscan.c
5. Make it possible to configure NUMA systems without page migration
and non-NUMA systems with page migration.I had to so some #ifdeffing in mempolicy.c that may need a cleanup.
Signed-off-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The alien cache rotor in mm/slab.c assumes that the first online node is
node 0. Eventually for some archs, especially with hotplug, this will no
longer be true.Fix the interleave rotor to handle the general case of node numbering.
Signed-off-by: Paul Jackson
Acked-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Fix bogus node loop in hugetlb.c alloc_fresh_huge_page(), which was
assuming that nodes are numbered contiguously from 0 to num_online_nodes().
Once the hotplug folks get this far, that will be false.Signed-off-by: Paul Jackson
Acked-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When we've allocated SWAPFILE_CLUSTER pages, ->cluster_next should be the
first index of swap cluster. But current code probably sets it wrong offset.Signed-off-by: Akinobu Mita
Acked-by: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
1. Only disable interrupts if there is actually something to free
2. Only dirty the pcp cacheline if we actually freed something.
3. Disable interrupts for each single pcp and not for cleaning
all the pcps in all zones of a node.drain_node_pages is called every 2 seconds from cache_reap. This
fix should avoid most disabling of interrupts.Signed-off-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The list_lock also protects the shared array and we call drain_array() with
the shared array. Therefore we cannot go as far as I wanted to but have to
take the lock in a way so that it also protects the array_cache in
drain_pages.(Note: maybe we should make the array_cache locking more consistent? I.e.
always take the array cache lock for shared arrays and disable interrupts
for the per cpu arrays?)Signed-off-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Remove drain_array_locked and use that opportunity to limit the time the l3
lock is taken further.Signed-off-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
And a parameter to drain_array to control the freeing of all objects and
then use drain_array() to replace instances of drain_array_locked with
drain_array. Doing so will avoid taking locks in those locations if the
arrays are empty.Signed-off-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
cache_reap takes the l3->list_lock (disabling interrupts) unconditionally
and then does a few checks and maybe does some cleanup. This patch makes
cache_reap() only take the lock if there is work to do and then the lock is
taken and released for each cleaning action.The checking of when to do the next reaping is done without any locking and
becomes racy. Should not matter since reaping can also be skipped if the
slab mutex cannot be acquired.The same is true for the touched processing. If we get this wrong once in
awhile then we will mistakenly clean or not clean the shared cache. This
will impact performance slightly.Note that the additional drain_array() function introduced here will fall
out in a subsequent patch since array cleaning will now be very similar
from all callers.Signed-off-by: Christoph Lameter
Cc: Pekka Enberg
Cc: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Make shrink_all_memory() repeat the attempts to free more memory if there
seems to be no pages to free.Signed-off-by: Rafael J. Wysocki
Cc: Pavel Machek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
follow_hugetlb_page() walks a range of user virtual address and then fills
in list of struct page * into an array that is passed from the argument
list. It also gets a reference count via get_page(). For compound page,
get_page() actually traverse back to head page via page_private() macro and
then adds a reference count to the head page. Since we are doing a virt to
pte look up, kernel already has a struct page pointer into the head page.
So instead of traverse into the small unit page struct and then follow a
link back to the head page, optimize that with incrementing the reference
count directly on the head page.The benefit is that we don't take a cache miss on accessing page struct for
the corresponding user address and more importantly, not to pollute the
cache with a "not very useful" round trip of pointer chasing. This adds a
moderate performance gain on an I/O intensive database transaction
workload.Signed-off-by: Ken Chen
Cc: David Gibson
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Implementation of hugetlbfs_counter() is functionally equivalent to
atomic_inc_return(). Use the simpler atomic form.Signed-off-by: Ken Chen
Cc: David Gibson
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Quite a long time back, prepare_hugepage_range() replaced
is_aligned_hugepage_range() as the callback from mm/mmap.c to arch code to
verify if an address range is suitable for a hugepage mapping.
is_aligned_hugepage_range() stuck around, but only to implement
prepare_hugepage_range() on archs which didn't implement their own.Most archs (everything except ia64 and powerpc) used the same
implementation of is_aligned_hugepage_range(). On powerpc, which
implements its own prepare_hugepage_range(), the custom version was never
used.In addition, "is_aligned_hugepage_range()" was a bad name, because it
suggests it returns true iff the given range is a good hugepage range,
whereas in fact it returns 0-or-error (so the sense is reversed).This patch cleans up by abolishing is_aligned_hugepage_range(). Instead
prepare_hugepage_range() is defined directly. Most archs use the default
version, which simply checks the given region is aligned to the size of a
hugepage. ia64 and powerpc define custom versions. The ia64 one simply
checks that the range is in the correct address space region in addition to
being suitably aligned. The powerpc version (just as previously) checks
for suitable addresses, and if necessary performs low-level MMU frobbing to
set up new areas for use by hugepages.No libhugetlbfs testsuite regressions on ppc64 (POWER5 LPAR).
Signed-off-by: David Gibson
Signed-off-by: Zhang Yanmin
Cc: "David S. Miller"
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: William Lee Irwin III
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The optional hugepage callback, hugetlb_free_pgd_range() is presently
implemented non-trivially only on ia64 (but I plan to add one for powerpc
shortly). It has its own prototype for the function in asm-ia64/pgtable.h.
However, since the function is called from generic code, it make sense for
its prototype to be in the generic hugetlb.h header file, as the protypes
other arch callbacks already are (prepare_hugepage_range(),
set_huge_pte_at(), etc.). This patch makes it so.Signed-off-by: David Gibson
Cc: William Lee Irwin III
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Turns out the hugepage logic in free_pgtables() was doubly broken. The
loop coalescing multiple normal page VMAs into one call to free_pgd_range()
had an off by one error, which could mean it would coalesce one hugepage
VMA into the same bundle (checking 'vma' not 'next' in the loop). I
transferred this bug into the new is_vm_hugetlb_page() based version.
Here's the fix.This one didn't bite on powerpc previously for the same reason the
is_hugepage_only_range() problem didn't: powerpc's hugetlb_free_pgd_range()
is identical to free_pgd_range(). It didn't bite on ia64 because the
hugepage region is distant enough from any other region that the separated
PMD_SIZE distance test would always prevent coalescing the two together.No libhugetlbfs testsuite regressions (ppc64, POWER5).
Signed-off-by: David Gibson
Cc: William Lee Irwin III
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
free_pgtables() has special logic to call hugetlb_free_pgd_range() instead
of the normal free_pgd_range() on hugepage VMAs. However, the test it uses
to do so is incorrect: it calls is_hugepage_only_range on a hugepage sized
range at the start of the vma. is_hugepage_only_range() will return true
if the given range has any intersection with a hugepage address region, and
in this case the given region need not be hugepage aligned. So, for
example, this test can return true if called on, say, a 4k VMA immediately
preceding a (nicely aligned) hugepage VMA.At present we get away with this because the powerpc version of
hugetlb_free_pgd_range() is just a call to free_pgd_range(). On ia64 (the
only other arch with a non-trivial is_hugepage_only_range()) we get away
with it for a different reason; the hugepage area is not contiguous with
the rest of the user address space, and VMAs are not permitted in between,
so the test can't return a false positive there.Nonetheless this should be fixed. We do that in the patch below by
replacing the is_hugepage_only_range() test with an explicit test of the
VMA using is_vm_hugetlb_page().This in turn changes behaviour for platforms where is_hugepage_only_range()
returns false always (everything except powerpc and ia64). We address this
by ensuring that hugetlb_free_pgd_range() is defined to be identical to
free_pgd_range() (instead of a no-op) on everything except ia64. Even so,
it will prevent some otherwise possible coalescing of calls down to
free_pgd_range(). Since this only happens for hugepage VMAs, removing this
small optimization seems unlikely to cause any trouble.This patch causes no regressions on the libhugetlbfs testsuite - ppc64
POWER5 (8-way), ppc64 G5 (2-way) and i386 Pentium M (UP).Signed-off-by: David Gibson
Cc: William Lee Irwin III
Acked-by: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Originally, mm/hugetlb.c just handled the hugepage physical allocation path
and its {alloc,free}_huge_page() functions were used from the arch specific
hugepage code. These days those functions are only used with mm/hugetlb.c
itself. Therefore, this patch makes them static and removes their
prototypes from hugetlb.h. This requires a small rearrangement of code in
mm/hugetlb.c to avoid a forward declaration.This patch causes no regressions on the libhugetlbfs testsuite (ppc64,
POWER5).Signed-off-by: David Gibson
Cc: William Lee Irwin III
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
These days, hugepages are demand-allocated at first fault time. There's a
somewhat dubious (and racy) heuristic when making a new mmap() to check if
there are enough available hugepages to fully satisfy that mapping.A particularly obvious case where the heuristic breaks down is where a
process maps its hugepages not as a single chunk, but as a bunch of
individually mmap()ed (or shmat()ed) blocks without touching and
instantiating the pages in between allocations. In this case the size of
each block is compared against the total number of available hugepages.
It's thus easy for the process to become overcommitted, because each block
mapping will succeed, although the total number of hugepages required by
all blocks exceeds the number available. In particular, this defeats such
a program which will detect a mapping failure and adjust its hugepage usage
downward accordingly.The patch below addresses this problem, by strictly reserving a number of
physical hugepages for hugepage inodes which have been mapped, but not
instatiated. MAP_SHARED mappings are thus "safe" - they will fail on
mmap(), not later with an OOM SIGKILL. MAP_PRIVATE mappings can still
trigger an OOM. (Actually SHARED mappings can technically still OOM, but
only if the sysadmin explicitly reduces the hugepage pool between mapping
and instantiation)This patch appears to address the problem at hand - it allows DB2 to start
correctly, for instance, which previously suffered the failure described
above.This patch causes no regressions on the libhugetblfs testsuite, and makes a
test (designed to catch this problem) pass which previously failed (ppc64,
POWER5).Signed-off-by: David Gibson
Cc: William Lee Irwin III
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Currently, no lock or mutex is held between allocating a hugepage and
inserting it into the pagetables / page cache. When we do go to insert the
page into pagetables or page cache, we recheck and may free the newly
allocated hugepage. However, since the number of hugepages in the system
is strictly limited, and it's usualy to want to use all of them, this can
still lead to spurious allocation failures.For example, suppose two processes are both mapping (MAP_SHARED) the same
hugepage file, large enough to consume the entire available hugepage pool.
If they race instantiating the last page in the mapping, they will both
attempt to allocate the last available hugepage. One will fail, of course,
returning OOM from the fault and thus causing the process to be killed,
despite the fact that the entire mapping can, in fact, be instantiated.The patch fixes this race by the simple method of adding a (sleeping) mutex
to serialize the hugepage fault path between allocation and insertion into
pagetables and/or page cache. It would be possible to avoid the
serialization by catching the allocation failures, waiting on some
condition, then rechecking to see if someone else has instantiated the page
for us. Given the likely frequency of hugepage instantiations, it seems
very doubtful it's worth the extra complexity.This patch causes no regression on the libhugetlbfs testsuite, and one
test, which can trigger this race now passes where it previously failed.Actually, the test still sometimes fails, though less often and only as a
shmat() failure, rather processes getting OOM killed by the VM. The dodgy
heuristic tests in fs/hugetlbfs/inode.c for whether there's enough hugepage
space aren't protected by the new mutex, and would be ugly to do so, so
there's still a race there. Another patch to replace those tests with
something saner for this reason as well as others coming...Signed-off-by: David Gibson
Cc: William Lee Irwin III
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Move the loops used in mm/hugetlb.c to clear and copy hugepages to their
own functions for clarity. As we do so, we add some checks of need_resched
- we are, after all copying megabytes of memory here. We also add
might_sleep() accordingly. We generally dropped locks around the clear and
copy, already but not everyone has PREEMPT enabled, so we should still be
checking explicitly.For this to work, we need to remove the clear_huge_page() from
alloc_huge_page(), which is called with the page_table_lock held in the COW
path. We move the clear_huge_page() to just after the alloc_huge_page() in
the hugepage no-page path. In the COW path, the new page is about to be
copied over, so clearing it was just a waste of time anyway. So as a side
effect we also fix the fact that we held the page_table_lock for far too
long in this path by calling alloc_huge_page() under it.It causes no regressions on the libhugetlbfs testsuite (ppc64, POWER5).
Signed-off-by: David Gibson
Cc: William Lee Irwin III
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
2.6.16-rc3 uses hugetlb on-demand paging, but it doesn_t support hugetlb
mprotect.From: David Gibson
Remove a test from the mprotect() path which checks that the mprotect()ed
range on a hugepage VMA is hugepage aligned (yes, really, the sense of
is_aligned_hugepage_range() is the opposite of what you'd guess :-/).In fact, we don't need this test. If the given addresses match the
beginning/end of a hugepage VMA they must already be suitably aligned. If
they don't, then mprotect_fixup() will attempt to split the VMA. The very
first test in split_vma() will check for a badly aligned address on a
hugepage VMA and return -EINVAL if necessary.From: "Chen, Kenneth W"
On i386 and x86-64, pte flag _PAGE_PSE collides with _PAGE_PROTNONE. The
identify of hugetlb pte is lost when changing page protection via mprotect.
A page fault occurs later will trigger a bug check in huge_pte_alloc().The fix is to always make new pte a hugetlb pte and also to clean up
legacy code where _PAGE_PRESENT is forced on in the pre-faulting day.Signed-off-by: Zhang Yanmin
Cc: David Gibson
Cc: "David S. Miller"
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: William Lee Irwin III
Signed-off-by: Ken Chen
Signed-off-by: Nishanth Aravamudan
Cc: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The current current get_init_ra_size is not optimal across different IO
sizes and max_readahead values. Here is a quick summary of sizes computed
under current design and under the attached patch. All of these assume 1st
IO at offset 0, or 1st detected sequential IO.32k max, 4k request
old new
-----------------
8k 8k
16k 16k
32k 32k128k max, 4k request
old new
-----------------
32k 16k
64k 32k
128k 64k
128k 128k128k max, 32k request
old new
-----------------
32k 64k
Cc: Steven Pratt
Cc: Ram Pai
Cc: Trond Myklebust
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
If get_next_ra_size() does not grow fast enough, ->prev_page can overrun
the ahead window. This means the caller will read the pages from
->ahead_start + ->ahead_size to ->prev_page synchronously.Signed-off-by: Oleg Nesterov
Cc: Steven Pratt
Cc: Ram Pai
Cc: Trond Myklebust
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
shmem.c was named and shamed in Jesper's "Building 100 kernels" warnings:
shmem_parse_mpol is only used when CONFIG_TMPFS parses mount options; and
only called from that one site, so mark it inline like its non-NUMA stub.Signed-off-by: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
As suggested by Marcelo:
1. The optimization introduced recently for not calling
page_referenced() during zone reclaim makes two additional checks in
shrink_list unnecessary.2. The if (unlikely(sc->may_swap)) in refill_inactive_zone is optimized
for the zone_reclaim case. However, most peoples system only does swap.
Undo that.Signed-off-by: Christoph Lameter
Cc: Marcelo Tosatti
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Remove the inlining of the new vs old mmap system call common code. This
reduces the size of the resulting vmlinux for defconfig as follows:mb@pc1:~/develop/git/linux-2.6$ size vmlinux.mmap*
text data bss dec hex filename
3303749 521524 186564 4011837 3d373d vmlinux.mmapinline
3303557 521524 186564 4011645 3d367d vmlinux.mmapnoinlineThe new sys_mmap2() has also one function call overhead removed, now.
(probably it was already optimized to a jmp before, but anyway...)Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Optimise page_count compound page test and make it consistent with similar
functions.Signed-off-by: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Put a few more checks under CONFIG_DEBUG_VM
Signed-off-by: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
prep_zero_page() uses KM_USER0 and hence may not be used from IRQ context, at
least for highmem pages.Cc: Nick Piggin
Cc: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Move the prep_ stuff into prep_new_page.
Signed-off-by: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
set_page_count usage outside mm/ is limited to setting the refcount to 1.
Remove set_page_count from outside mm/, and replace those users with
init_page_count() and set_page_refcounted().This allows more debug checking, and tighter control on how code is allowed
to play around with page->_count.Signed-off-by: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
A couple of places set_page_count(page, 1) that don't need to.
Signed-off-by: Nick Piggin
Cc: Paul Mackerras
Cc: Jeff Dike
Cc: Paolo 'Blaisorblade' Giarrusso
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Now that compound page handling is properly fixed in the VM, move nommu
over to using compound pages rather than rolling their own refcounting.nommu vm page refcounting is broken anyway, but there is no need to have
divergent code in the core VM now, nor when it gets fixed.Signed-off-by: Nick Piggin
Cc: David Howells(Needs testing, please).
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Remove __put_page from outside the core mm/. It is dangerous because it does
not handle compound pages nicely, and misses 1->0 transitions. If a user
later appears that really needs the extra speed we can reevaluate.Signed-off-by: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Remove page_count and __put_page from x86-64 pageattr
Signed-off-by: Nick Piggin
Acked-by: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Use page->lru.next to implement the singly linked list of pages rather than
the struct deferred_page which needs to be allocated and freed for each
page.Signed-off-by: Nick Piggin
Acked-by: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Stop using __put_page and page_count in i386 pageattr.c
Signed-off-by: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
sg increments the refcount of constituent pages in its higher order memory
allocations when they are about to be mapped by userspace. This is done so
the subsequent get_page/put_page when doing the mapping and unmapping does not
free the page.Move over to the preferred way, that is, using compound pages instead. This
fixes a whole class of possible obscure bugs where a get_user_pages on a
constituent page may outlast the user mappings or even the driver.Signed-off-by: Nick Piggin
Cc: Hugh Dickins
Cc: Douglas Gilbert
Cc: James Bottomley
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Now that it's madvisable, remove two pieces of VM_DONTCOPY bogosity:
1. There was and is no logical reason why VM_DONTCOPY should be in the
list of flags which forbid vma merging (and those drivers which set
it are also setting VM_IO, which itself forbids the merge).2. It's hard to understand the purpose of the VM_HUGETLB, VM_DONTCOPY
block in vm_stat_account: but never mind, it's under CONFIG_HUGETLB,
which (unlike CONFIG_HUGETLB_PAGE or CONFIG_HUGETLBFS) has never been
defined.Signed-off-by: Hugh Dickins
Cc: William Lee Irwin III
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
In shrink_inactive_list(), nr_scan is not accounted when nr_taken is 0.
But 0 pages taken does not mean 0 pages scanned.Move the goto statement below the accounting code to fix it.
Signed-off-by: Wu Fengguang
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
