2005-04-16 15:20:36 -07:00
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2006-01-09 15:59:24 -08:00
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2005-04-16 15:20:36 -07:00
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2006-01-09 15:59:24 -08:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:41 -07:00
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2006-01-18 17:42:27 -08:00
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[PATCH] swap: swap_lock replace list+device
The idea of a swap_device_lock per device, and a swap_list_lock over them all,
is appealing; but in practice almost every holder of swap_device_lock must
already hold swap_list_lock, which defeats the purpose of the split.
The only exceptions have been swap_duplicate, valid_swaphandles and an
untrodden path in try_to_unuse (plus a few places added in this series).
valid_swaphandles doesn't show up high in profiles, but swap_duplicate does
demand attention. However, with the hold time in get_swap_pages so much
reduced, I've not yet found a load and set of swap device priorities to show
even swap_duplicate benefitting from the split. Certainly the split is mere
overhead in the common case of a single swap device.
So, replace swap_list_lock and swap_device_lock by spinlock_t swap_lock
(generally we seem to prefer an _ in the name, and not hide in a macro).
If someone can show a regression in swap_duplicate, then probably we should
add a hashlock for the swap_map entries alone (shorts being anatomic), so as
to help the case of the single swap device too.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-03 15:54:41 -07:00
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2005-04-16 15:20:36 -07:00
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2006-02-01 03:05:38 -08:00
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2005-04-16 15:20:36 -07:00
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2006-02-01 03:05:39 -08:00
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2006-02-01 03:05:41 -08:00
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2006-02-01 03:05:39 -08:00
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2005-04-16 15:20:36 -07:00
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[PATCH] unpaged: anon in VM_UNPAGED
copy_one_pte needs to copy the anonymous COWed pages in a VM_UNPAGED area,
zap_pte_range needs to free them, do_wp_page needs to COW them: just like
ordinary pages, not like the unpaged.
But recognizing them is a little subtle: because PageReserved is no longer a
condition for remap_pfn_range, we can now mmap all of /dev/mem (whether the
distro permits, and whether it's advisable on this or that architecture, is
another matter). So if we can see a PageAnon, it may not be ours to mess with
(or may be ours from elsewhere in the address space). I suspect there's an
entertaining insoluble self-referential problem here, but the page_is_anon
function does a good practical job, and MAP_PRIVATE PROT_WRITE VM_UNPAGED will
always be an odd choice.
In updating the comment on page_address_in_vma, noticed a potential NULL
dereference, in a path we don't actually take, but fixed it.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-21 21:32:18 -08:00
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2005-04-16 15:20:36 -07:00
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[PATCH] unpaged: anon in VM_UNPAGED
copy_one_pte needs to copy the anonymous COWed pages in a VM_UNPAGED area,
zap_pte_range needs to free them, do_wp_page needs to COW them: just like
ordinary pages, not like the unpaged.
But recognizing them is a little subtle: because PageReserved is no longer a
condition for remap_pfn_range, we can now mmap all of /dev/mem (whether the
distro permits, and whether it's advisable on this or that architecture, is
another matter). So if we can see a PageAnon, it may not be ours to mess with
(or may be ours from elsewhere in the address space). I suspect there's an
entertaining insoluble self-referential problem here, but the page_is_anon
function does a good practical job, and MAP_PRIVATE PROT_WRITE VM_UNPAGED will
always be an odd choice.
In updating the comment on page_address_in_vma, noticed a potential NULL
dereference, in a path we don't actually take, but fixed it.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-21 21:32:18 -08:00
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2005-04-16 15:20:36 -07:00
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2005-05-01 08:58:36 -07:00
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2005-10-29 18:16:41 -07:00
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2005-05-01 08:58:36 -07:00
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2005-06-23 22:05:25 -07:00
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2005-10-29 18:16:31 -07:00
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2005-05-01 08:58:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-05-01 08:58:36 -07:00
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2005-10-29 18:16:31 -07:00
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[PATCH] mm: split page table lock
Christoph Lameter demonstrated very poor scalability on the SGI 512-way, with
a many-threaded application which concurrently initializes different parts of
a large anonymous area.
This patch corrects that, by using a separate spinlock per page table page, to
guard the page table entries in that page, instead of using the mm's single
page_table_lock. (But even then, page_table_lock is still used to guard page
table allocation, and anon_vma allocation.)
In this implementation, the spinlock is tucked inside the struct page of the
page table page: with a BUILD_BUG_ON in case it overflows - which it would in
the case of 32-bit PA-RISC with spinlock debugging enabled.
Splitting the lock is not quite for free: another cacheline access. Ideally,
I suppose we would use split ptlock only for multi-threaded processes on
multi-cpu machines; but deciding that dynamically would have its own costs.
So for now enable it by config, at some number of cpus - since the Kconfig
language doesn't support inequalities, let preprocessor compare that with
NR_CPUS. But I don't think it's worth being user-configurable: for good
testing of both split and unsplit configs, split now at 4 cpus, and perhaps
change that to 8 later.
There is a benefit even for singly threaded processes: kswapd can be attacking
one part of the mm while another part is busy faulting.
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 18:16:40 -07:00
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2005-10-29 18:16:31 -07:00
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2005-05-01 08:58:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-05-01 08:58:36 -07:00
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2005-04-16 15:20:36 -07:00
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2005-11-28 13:44:07 -08:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-11-28 13:44:07 -08:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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2005-11-28 13:44:07 -08:00
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2005-04-16 15:20:36 -07:00
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2005-11-28 13:44:07 -08:00
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2005-04-16 15:20:36 -07:00
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2005-11-28 13:44:07 -08:00
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2005-04-16 15:20:36 -07:00
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2005-11-28 13:44:07 -08:00
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2005-04-16 15:20:36 -07:00
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2005-11-28 13:44:07 -08:00
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2005-04-16 15:20:36 -07:00
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2005-11-28 13:44:07 -08:00
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2005-04-16 15:20:36 -07:00
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2005-11-28 13:44:07 -08:00
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2005-04-16 15:20:36 -07:00
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2005-11-28 13:44:07 -08:00
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2005-04-16 15:20:36 -07:00
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2006-01-06 00:11:12 -08:00
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2006-01-06 00:11:20 -08:00
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2006-01-06 00:11:12 -08:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:41 -07:00
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2005-04-16 15:20:36 -07:00
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2006-01-06 00:11:12 -08:00
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2005-04-16 15:20:36 -07:00
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2006-01-06 00:11:12 -08:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:41 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:12 -07:00
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2005-04-16 15:20:36 -07:00
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2006-01-06 00:11:20 -08:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:41 -07:00
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2005-04-16 15:20:36 -07:00
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2006-01-08 01:01:00 -08:00
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2005-04-16 15:20:36 -07:00
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2006-01-06 00:11:20 -08:00
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2005-04-16 15:20:36 -07:00
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2006-02-01 03:05:38 -08:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-05-01 08:58:36 -07:00
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2005-04-16 15:20:36 -07:00
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2005-11-21 21:32:16 -08:00
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2006-02-01 03:05:38 -08:00
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2005-04-16 15:20:36 -07:00
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[PATCH] mm: update_hiwaters just in time
update_mem_hiwater has attracted various criticisms, in particular from those
concerned with mm scalability. Originally it was called whenever rss or
total_vm got raised. Then many of those callsites were replaced by a timer
tick call from account_system_time. Now Frank van Maarseveen reports that to
be found inadequate. How about this? Works for Frank.
Replace update_mem_hiwater, a poor combination of two unrelated ops, by macros
update_hiwater_rss and update_hiwater_vm. Don't attempt to keep
mm->hiwater_rss up to date at timer tick, nor every time we raise rss (usually
by 1): those are hot paths. Do the opposite, update only when about to lower
rss (usually by many), or just before final accounting in do_exit. Handle
mm->hiwater_vm in the same way, though it's much less of an issue. Demand
that whoever collects these hiwater statistics do the work of taking the
maximum with rss or total_vm.
And there has been no collector of these hiwater statistics in the tree. The
new convention needs an example, so match Frank's usage by adding a VmPeak
line above VmSize to /proc/<pid>/status, and also a VmHWM line above VmRSS
(High-Water-Mark or High-Water-Memory).
There was a particular anomaly during mremap move, that hiwater_vm might be
captured too high. A fleeting such anomaly remains, but it's quickly
corrected now, whereas before it would stick.
What locking? None: if the app is racy then these statistics will be racy,
it's not worth any overhead to make them exact. But whenever it suits,
hiwater_vm is updated under exclusive mmap_sem, and hiwater_rss under
page_table_lock (for now) or with preemption disabled (later on): without
going to any trouble, minimize the time between reading current values and
updating, to minimize those occasions when a racing thread bumps a count up
and back down in between.
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 18:16:18 -07:00
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2005-04-16 15:20:36 -07:00
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[PATCH] mm: split page table lock
Christoph Lameter demonstrated very poor scalability on the SGI 512-way, with
a many-threaded application which concurrently initializes different parts of
a large anonymous area.
This patch corrects that, by using a separate spinlock per page table page, to
guard the page table entries in that page, instead of using the mm's single
page_table_lock. (But even then, page_table_lock is still used to guard page
table allocation, and anon_vma allocation.)
In this implementation, the spinlock is tucked inside the struct page of the
page table page: with a BUILD_BUG_ON in case it overflows - which it would in
the case of 32-bit PA-RISC with spinlock debugging enabled.
Splitting the lock is not quite for free: another cacheline access. Ideally,
I suppose we would use split ptlock only for multi-threaded processes on
multi-cpu machines; but deciding that dynamically would have its own costs.
So for now enable it by config, at some number of cpus - since the Kconfig
language doesn't support inequalities, let preprocessor compare that with
NR_CPUS. But I don't think it's worth being user-configurable: for good
testing of both split and unsplit configs, split now at 4 cpus, and perhaps
change that to 8 later.
There is a benefit even for singly threaded processes: kswapd can be attacking
one part of the mm while another part is busy faulting.
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 18:16:40 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:41 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:05 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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[PATCH] mm: update_hiwaters just in time
update_mem_hiwater has attracted various criticisms, in particular from those
concerned with mm scalability. Originally it was called whenever rss or
total_vm got raised. Then many of those callsites were replaced by a timer
tick call from account_system_time. Now Frank van Maarseveen reports that to
be found inadequate. How about this? Works for Frank.
Replace update_mem_hiwater, a poor combination of two unrelated ops, by macros
update_hiwater_rss and update_hiwater_vm. Don't attempt to keep
mm->hiwater_rss up to date at timer tick, nor every time we raise rss (usually
by 1): those are hot paths. Do the opposite, update only when about to lower
rss (usually by many), or just before final accounting in do_exit. Handle
mm->hiwater_vm in the same way, though it's much less of an issue. Demand
that whoever collects these hiwater statistics do the work of taking the
maximum with rss or total_vm.
And there has been no collector of these hiwater statistics in the tree. The
new convention needs an example, so match Frank's usage by adding a VmPeak
line above VmSize to /proc/<pid>/status, and also a VmHWM line above VmRSS
(High-Water-Mark or High-Water-Memory).
There was a particular anomaly during mremap move, that hiwater_vm might be
captured too high. A fleeting such anomaly remains, but it's quickly
corrected now, whereas before it would stick.
What locking? None: if the app is racy then these statistics will be racy,
it's not worth any overhead to make them exact. But whenever it suits,
hiwater_vm is updated under exclusive mmap_sem, and hiwater_rss under
page_table_lock (for now) or with preemption disabled (later on): without
going to any trouble, minimize the time between reading current values and
updating, to minimize those occasions when a racing thread bumps a count up
and back down in between.
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 18:16:18 -07:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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2005-11-28 14:34:23 -08:00
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2005-04-16 15:20:36 -07:00
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2005-11-29 11:45:26 -08:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:05 -07:00
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2005-04-16 15:20:36 -07:00
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2005-10-29 18:16:31 -07:00
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2005-04-16 15:20:36 -07:00
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2006-02-01 03:05:38 -08:00
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2005-04-16 15:20:36 -07:00
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2006-02-01 03:05:38 -08:00
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2005-04-16 15:20:36 -07:00
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2006-02-01 03:05:38 -08:00
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2005-04-16 15:20:36 -07:00
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2006-02-01 03:05:38 -08:00
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2005-04-16 15:20:36 -07:00
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2005-11-21 21:32:16 -08:00
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2005-04-16 15:20:36 -07:00
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2005-11-21 21:32:16 -08:00
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2005-04-16 15:20:36 -07:00
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2005-09-03 15:54:43 -07:00
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2005-04-16 15:20:36 -07:00
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2005-11-21 21:32:16 -08:00
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2005-04-16 15:20:36 -07:00
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2006-02-01 03:05:38 -08:00
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2005-04-16 15:20:36 -07:00
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2006-02-01 03:05:38 -08:00
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2005-04-16 15:20:36 -07:00
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2006-02-01 03:05:38 -08:00
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2005-04-16 15:20:36 -07:00
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2005-05-01 08:58:36 -07:00
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