- 05 Feb, 2008 40 commits
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Christoph Lameter authored
- Add comments explaing how drain_pages() works. - Eliminate useless functions - Rename drain_all_local_pages to drain_all_pages(). It does drain all pages not only those of the local processor. - Eliminate useless interrupt off / on sequences. drain_pages() disables interrupts on its own. The execution thread is pinned to processor by the caller. So there is no need to disable interrupts. - Put drain_all_pages() declaration in gfp.h and remove the declarations from suspend.h and from mm/memory_hotplug.c - Make software suspend call drain_all_pages(). The draining of processor local pages is may not the right approach if software suspend wants to support SMP. If they call drain_all_pages then we can make drain_pages() static. [akpm@linux-foundation.org: fix build] Signed-off-by:
Christoph Lameter <clameter@sgi.com> Acked-by:
Mel Gorman <mel@csn.ul.ie> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Daniel Walker <dwalker@mvista.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Nick Piggin authored
Most pagecache (and some other) radix tree insertions have the great opportunity to preallocate a few nodes with relaxed gfp flags. But the preallocation is squandered when it comes time to allocate a node, we default to first attempting a GFP_ATOMIC allocation -- that doesn't normally fail, but it can eat into atomic memory reserves that we don't need to be using. Another upshot of this is that it removes the sometimes highly contended zone->lock from underneath tree_lock. Pagecache insertions are always performed with a radix tree preload, and after this change, such a situation will never fall back to kmem_cache_alloc within radix_tree_node_alloc. David Miller reports seeing this allocation fail on a highly threaded sparc64 system: [527319.459981] dd: page allocation failure. order:0, mode:0x20 [527319.460403] Call Trace: [527319.460568] [00000000004b71e0] __slab_alloc+0x1b0/0x6a8 [527319.460636] [00000000004b7bbc] kmem_cache_alloc+0x4c/0xa8 [527319.460698] [000000000055309c] radix_tree_node_alloc+0x20/0x90 [527319.460763] [0000000000553238] radix_tree_insert+0x12c/0x260 [527319.460830] [0000000000495cd0] add_to_page_cache+0x38/0xb0 [527319.460893] [00000000004e4794] mpage_readpages+0x6c/0x134 [527319.460955] [000000000049c7fc] __do_page_cache_readahead+0x170/0x280 [527319.461028] [000000000049cc88] ondemand_readahead+0x208/0x214 [527319.461094] [0000000000496018] do_generic_mapping_read+0xe8/0x428 [527319.461152] [0000000000497948] generic_file_aio_read+0x108/0x170 [527319.461217] [00000000004badac] do_sync_read+0x88/0xd0 [527319.461292] [00000000004bb5cc] vfs_read+0x78/0x10c [527319.461361] [00000000004bb920] sys_read+0x34/0x60 [527319.461424] [0000000000406294] linux_sparc_syscall32+0x3c/0x40 The calltrace is significant: __do_page_cache_readahead allocates a number of pages with GFP_KERNEL, and hence it should have reclaimed sufficient memory to satisfy GFP_ATOMIC allocations. However after the list of pages goes to mpage_readpages, there can be significant intervals (including disk IO) before all the pages are inserted into the radix-tree. So the reserves can easily be depleted at that point. The patch is confirmed to fix the problem. Signed-off-by:
Nick Piggin <npiggin@suse.de> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by:
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Adrian Bunk authored
__vmalloc_area_node() can become static. Signed-off-by:
Adrian Bunk <bunk@kernel.org> Signed-off-by:
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Balbir Singh authored
This code in mm/tiny-shmem.c is under #if 0 - remove it. Signed-off-by:
Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by:
Matt Mackall <mpm@selenic.com> Signed-off-by:
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Adrian Bunk authored
task_dirty_limit() can become static. Signed-off-by:
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Matt Mackall authored
Make /proc/ page monitoring configurable This puts the following files under an embedded config option: /proc/pid/clear_refs /proc/pid/smaps /proc/pid/pagemap /proc/kpagecount /proc/kpageflags [akpm@linux-foundation.org: Kconfig fix] Signed-off-by:
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Matt Mackall authored
This makes a subset of physical page flags available to userspace. Together with /proc/pid/kpagemap, this allows tracking of a wide variety of VM behaviors. Exported flags are decoupled from the kernel's internal flags. This allows us to reorder flag bits, and synthesize any bits that get redefined in terms of other bits. [akpm@linux-foundation.org: remove unneeded access_ok()] [akpm@linux-foundation.org: s/0/NULL/] Signed-off-by:
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Matt Mackall authored
This makes physical page map counts available to userspace. Together with /proc/pid/pagemap and /proc/pid/clear_refs, this can be used to monitor memory usage on a per-page basis. [akpm@linux-foundation.org: remove unneeded access_ok()] [bunk@stusta.de: make struct proc_kpagemap static] Signed-off-by:
Adrian Bunk <bunk@stusta.de> Cc: Dave Hansen <haveblue@us.ibm.com> Signed-off-by:
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Matt Mackall authored
This interface provides a mapping for each page in an address space to its physical page frame number, allowing precise determination of what pages are mapped and what pages are shared between processes. New in this version: - headers gone again (as recommended by Dave Hansen and Alan Cox) - 64-bit entries (as per discussion with Andi Kleen) - swap pte information exported (from Dave Hansen) - page walker callback for holes (from Dave Hansen) - direct put_user I/O (as suggested by Rusty Russell) This patch folds in cleanups and swap PTE support from Dave Hansen <haveblue@us.ibm.com>. Signed-off-by:
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Matt Mackall authored
Reorder source so that all the code and data for each interface is together. Signed-off-by:
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Matt Mackall authored
This puts all the clear_refs code where it belongs and probably lets things compile on MMU-less systems as well. Signed-off-by:
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Matt Mackall authored
This pulls the shared map display code out of show_map and puts it in show_smap where it belongs. Signed-off-by:
David Rientjes <rientjes@google.com> Cc: Dave Hansen <haveblue@us.ibm.com> Signed-off-by:
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Matt Mackall authored
Use the generic pagewalker for smaps and clear_refs Signed-off-by:
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Matt Mackall authored
Introduce a general page table walker Signed-off-by:
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Matt Mackall authored
Move is_swap_pte helper function to swapops.h for use by pagemap code Signed-off-by:
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Dave Hansen authored
The following replaces the earlier patches sent. It should address David Rientjes's comments, and has been compile tested on all the architectures that it touches, save for parisc. For the /proc/<pid>/pagemap code[1], we need to able to query how much virtual address space a particular task has. The trick is that we do it through /proc and can't use TASK_SIZE since it references "current" on some arches. The process opening the /proc file might be a 32-bit process opening a 64-bit process's pagemap file. x86_64 already has a TASK_SIZE_OF() macro: #define TASK_SIZE_OF(child) ((test_tsk_thread_flag(child, TIF_IA32)) ? IA32_PAGE_OFFSET : TASK_SIZE64) I'd like to have that for other architectures. So, add it for all the architectures that actually use "current" in their TASK_SIZE. For the others, just add a quick #define in sched.h to use plain old TASK_SIZE. 1. http://www.linuxworld.com/news/2007/042407-kernel.html - MIPS portion from Ralf Baechle <ralf@linux-mips.org> [akpm@linux-foundation.org: fix mips build] Signed-off-by:
Dave Hansen <haveblue@us.ibm.com> Signed-off-by:
Ralf Baechle <ralf@linux-mips.org> Signed-off-by:
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Fengguang Wu authored
The "proportional set size" (PSS) of a process is the count of pages it has in memory, where each page is divided by the number of processes sharing it. So if a process has 1000 pages all to itself, and 1000 shared with one other process, its PSS will be 1500. - lwn.net: "ELC: How much memory are applications really using?" The PSS proposed by Matt Mackall is a very nice metic for measuring an process's memory footprint. So collect and export it via /proc/<pid>/smaps. Matt Mackall's pagemap/kpagemap and John Berthels's exmap can also do the job. They are comprehensive tools. But for PSS, let's do it in the simple way. Cc: John Berthels <jjberthels@gmail.com> Cc: Bernardo Innocenti <bernie@codewiz.org> Cc: Padraig Brady <P@draigBrady.com> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by:Fengguang Wu <wfg@mail.ustc.edu.cn> Cc: Hugh Dickins <hugh@veritas.com> Cc: Dave Hansen <haveblue@us.ibm.com> Signed-off-by:
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Christoph Hellwig authored
vmtruncate is a twisted maze of gotos, this patch cleans it up to have a proper if else for the two major cases of extending and truncating truncate and thus makes it a lot more readable while keeping exactly the same functinality. Signed-off-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
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Hugh Dickins authored
Intensive swapoff testing shows shmem_unuse spinning on an entry in shmem_swaplist pointing to itself: how does that come about? Days pass... First guess is this: shmem_delete_inode tests list_empty without taking the global mutex (so the swapping case doesn't slow down the common case); but there's an instant in shmem_unuse_inode's list_move_tail when the list entry may appear empty (a rare case, because it's actually moving the head not the the list member). So there's a danger of leaving the inode on the swaplist when it's freed, then reinitialized to point to itself when reused. Fix that by skipping the list_move_tail when it's a no-op, which happens to plug this. But this same spinning then surfaces on another machine. Ah, I'd never suspected it, but shmem_writepage's swaplist manipulation is unsafe: though we still hold page lock, which would hold off inode deletion if the page were in pagecache, it doesn't hold off once it's in swapcache (free_swap_and_cache doesn't wait on locked pages). Hmm: we could put the the inode on swaplist earlier, but then shmem_unuse_inode could never prune unswapped inodes. Fix this with an igrab before dropping info->lock, as in shmem_unuse_inode; though I am a little uneasy about the iput which has to follow - it works, and I see nothing wrong with it, but it is surprising that shmem inode deletion may now occur below shmem_writepage. Revisit this fix later? And while we're looking at these races: the way shmem_unuse tests swapped without holding info->lock looks unsafe, if we've more than one swap area: a racing shmem_writepage on another page of the same inode could be putting it in swapcache, just as we're deciding to remove the inode from swaplist - there's a danger of going on swap without being listed, so a later swapoff would hang, being unable to locate the entry. Move that test and removal down into shmem_unuse_inode, once info->lock is held. Signed-off-by:
Hugh Dickins <hugh@veritas.com> Signed-off-by:
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Hugh Dickins authored
Nick has observed that shmem.c still uses GFP_ATOMIC when adding to page cache or swap cache, without any radix tree preload: so tending to deplete emergency reserves of memory. GFP_ATOMIC remains appropriate in shmem_writepage's add_to_swap_cache: it's being called under memory pressure, so must not wait for more memory to become available. But shmem_unuse_inode now has a window in which it can and should preload with GFP_KERNEL, and say GFP_NOWAIT instead of GFP_ATOMIC in its add_to_page_cache. shmem_getpage is not so straightforward: its filepage/swappage integrity relies upon exchanging between caches under spinlock, and it would need a lot of restructuring to place the preloads correctly. Instead, follow its pattern of retrying on races: use GFP_NOWAIT instead of GFP_ATOMIC in add_to_page_cache, and begin each circuit of the repeat loop with a sleeping radix_tree_preload, followed immediately by radix_tree_preload_end - that won't guarantee success in the next add_to_page_cache, but doesn't need to. And we can then remove that bothersome congestion_wait: when needed, it'll automatically get done in the course of the radix_tree_preload. Signed-off-by:
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Hugh Dickins authored
There are a couple of reasons (patches follow) why it would be good to open a window for sleep in shmem_unuse_inode, between its search for a matching swap entry, and its handling of the entry found. shmem_unuse_inode must then use igrab to hold the inode against deletion in that window, and its corresponding iput might result in deletion: so it had better unlock_page before the iput, and might as well release the page too. Nor is there any need to hold on to shmem_swaplist_mutex once we know we'll leave the loop. So this unwinding moves from try_to_unuse and shmem_unuse into shmem_unuse_inode, in the case when it finds a match. Let try_to_unuse break on error in the shmem_unuse case, as it does in the unuse_mm case: though at this point in the series, no error to break on. Signed-off-by:
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Hugh Dickins authored
shmem_unuse is at present an unbroken search through every swap vector page of every tmpfs file which might be swapped, all under shmem_swaplist_lock. This dates from long ago, when the caller held mmlist_lock over it all too: long gone, but there's never been much pressure for preemptible swapoff. Make it a little more preemptible, replacing shmem_swaplist_lock by shmem_swaplist_mutex, inserting a cond_resched in the main loop, and a cond_resched_lock (on info->lock) at one convenient point in the shmem_unuse_inode loop, where it has no outstanding kmap_atomic. If we're serious about preemptible swapoff, there's much further to go e.g. I'm stupid to let the kmap_atomics of the decreasingly significant HIGHMEM case dictate preemptiblility for other configs. But as in the earlier patch to make swapoff scan ptes preemptibly, my hidden agenda is really towards making memcgroups work, hardly about preemptibility at all. Signed-off-by:
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Hugh Dickins authored
tmpfs is expected to limit the memory used (unless mounted with nr_blocks=0 or size=0). But if a stacked filesystem such as unionfs gets pages from a sparse tmpfs file by reading holes, and then writes to them, it can easily exceed any such limit at present. So suppress the SGP_READ "don't allocate page" ZERO_PAGE optimization when reading for the kernel (a KERNEL_DS check, ugh, sorry about that). Indeed, pessimistically mark such pages as dirty, so they cannot get reclaimed and unaccounted by mistake. The venerable shmem_recalc_inode code (originally to account for the reclaim of clean pages) suffices to get the accounting right when swappages are dropped in favour of more uptodate filepages. This also fixes the NULL shmem_swp_entry BUG or oops in shmem_writepage, caused by unionfs writing to a very sparse tmpfs file: to minimize memory allocation in swapout, tmpfs requires the swap vector be allocated upfront, which wasn't always happening in this stacked case. Signed-off-by:
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Hugh Dickins authored
tmpfs has long allowed for a fresh filepage to be created in pagecache, just before shmem_getpage gets the chance to match it up with the swappage which already belongs to that offset. But unionfs_writepage now does a find_or_create_page, divorced from shmem_getpage, which leaves conflicting filepage and swappage outstanding indefinitely, when unionfs is over tmpfs. Therefore shmem_writepage (where a page is swizzled from file to swap) must now be on the lookout for existing swap, ready to free it in favour of the more uptodate filepage, instead of BUGging on that clash. And when the add_to_page_cache fails in shmem_unuse_inode, it must defer to an uptodate filepage, otherwise swapoff would hang. Whereas when add_to_page_cache fails in shmem_getpage, it should retry in the same way it already does. Signed-off-by:
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Hugh Dickins authored
move_to_swap_cache and move_from_swap_cache functions (which swizzle a page between tmpfs page cache and swap cache, to avoid page copying) are only used by shmem.c; and our subsequent fix for unionfs needs different treatments in the two instances of move_from_swap_cache. Move them from swap_state.c into their callsites shmem_writepage, shmem_unuse_inode and shmem_getpage, making add_to_swap_cache externally visible. shmem.c likes to say set_page_dirty where swap_state.c liked to say SetPageDirty: respect that diversity, which __set_page_dirty_no_writeback makes moot (and implies we should lose that "shift page from clean_pages to dirty_pages list" comment: it's on neither). Signed-off-by:
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Hugh Dickins authored
add_to_swap_cache doesn't amount to much: merge it into its sole caller read_swap_cache_async. But we'll be needing to call __add_to_swap_cache from shmem.c, so promote it to the new add_to_swap_cache. Both were static, so there's no interface confusion to worry about. And lose that inappropriate "Anon pages are already on the LRU" comment in the merging: they're not already on the LRU, as Nick Piggin noticed. Signed-off-by:
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Hugh Dickins authored
Both unionfs and memcgroups pose challenges to tmpfs and shmem. To help fix, it's best to move the swap swizzling functions from swap_state.c to shmem.c. As a preliminary to that, move swap stats updating down into __add_to_swap_cache, which will remain internal to swap_state.c. Well, actually, just move down the incrementation of add_total: remove noent_race and exist_race completely, they are relics of my 2.4.11 testing. Alt-SysRq-m users will be thrilled if 2.6.25 is at last free of "race M+N"s. Signed-off-by:
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Michael Marineau authored
When tmpfs is mounted with a size less than one page, the number of blocks is set to 0 which makes the tmpfs mount unlimited. This can lead to a quick and surprising death if someone typos a tmpfs mount command and writes too much. tmpfs can still be mounted as unlimited if size or nr_blocks is exactly 0, as Documentation/filesystems/tmpfs.txt says. Hugh: do this by rounding size up instead of down in all cases: which slightly expands other odd-sized tmpfs mounts, but in a consistent way. Signed-off-by:
Michael Marineau <mike@marineau.org> Signed-off-by:
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Pavel Emelyanov authored
The shmem_sb_info structure has a number of free_inodes. This value is altered in appropriate places under spinlock and with the sbi->max_inodes != 0 check. Consolidate these manipulations into two helpers. This is minus 42 bytes of shmem.o and minus 4 :) lines of code. [akpm@linux-foundation.org: fix error return values] Signed-off-by:
Pavel Emelyanov <xemul@openvz.org> Signed-off-by:
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Hugh Dickins authored
Provided that CONFIG_HIGHPTE is not set, unuse_pte_range can reduce latency in swapoff by scanning the page table preemptibly: so long as unuse_pte is careful to recheck that entry under pte lock. (To tell the truth, this patch was not inspired by any cries for lower latency here: rather, this restructuring permits a future memory controller patch to allocate with GFP_KERNEL in unuse_pte, where before it could not. But it would be wrong to tuck this change away inside a memcgroup patch.) Signed-off-by:
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Hugh Dickins authored
valid_swaphandles is supposed to do a quick pass over the swap map entries neigbouring the entry which swapin_readahead is targetting, to determine for it a range worth reading all together. But since it always starts its search from the beginning of the swap "cluster", a reject (free entry) there immediately curtails the readaround, and every swapin_readahead from that cluster is for just a single page. Instead scan forwards and backwards around the target entry. Use better names for some variables: a swap_info pointer is usually called "si" not "swapdev". And at the end, if only the target page should be read, return count of 0 to disable readaround, to avoid the unnecessarily repeated call to read_swap_cache_async. Signed-off-by:
Rik van Riel <riel@surriel.com> Signed-off-by:
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Hugh Dickins authored
With the old aops, writing to a tmpfs file had to use its own special method: the generic method would pass in a fresh page to prepare_write when the right page was there in swapcache - which was inefficient to handle, even once we'd concocted the code to handle it. With the new aops, the generic method uses shmem_write_end, which lets shmem_getpage find the right page: so now abandon shmem_file_write in favour of the generic method. Yes, that does do several things that tmpfs hasn't really needed (notably balance_dirty_pages_ratelimited, which ramfs also calls); but more use of common code is preferable. Signed-off-by:
Rik van Riel <riel@redhat.com> Signed-off-by:
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Hugh Dickins authored
In the new aops, write_begin is supposed to return the page locked: though I've seen no ill effects, that's been overlooked in the case of shmem_write_begin, and should be fixed. Then shmem_write_end must unlock the page: do so _after_ updating i_size, as we found to be important in other filesystems (though since shmem pages don't go the usual writeback route, they never suffered from that corruption). For shmem_write_begin to return the page locked, we need shmem_getpage to return the page locked in SGP_WRITE case as well as SGP_CACHE case: let's simplify the interface and return it locked even when SGP_READ. Signed-off-by:
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Hugh Dickins authored
Remove SGP_QUICK from the sgp_type enum: it was for shmem_populate and has no users now. Remove SGP_FAULT from the enum: SGP_CACHE does just as well (and shmem_getpage is about to return with page always locked). Signed-off-by:
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Hugh Dickins authored
Building in a filesystem on a loop device on a tmpfs file can hang when swapping, the loop thread caught in that infamous throttle_vm_writeout. In theory this is a long standing problem, which I've either never seen in practice, or long ago suppressed the recollection, after discounting my load and my tmpfs size as unrealistically high. But now, with the new aops, it has become easy to hang on one machine. Loop used to grab_cache_page before the old prepare_write to tmpfs, which seems to have been enough to free up some memory for any swapin needed; but the new write_begin lets tmpfs find or allocate the page (much nicer, since grab_cache_page missed tmpfs pages in swapcache). When allocating a fresh page, tmpfs respects loop's mapping_gfp_mask, which has __GFP_IO|__GFP_FS stripped off, and throttle_vm_writeout is designed to break out when __GFP_IO or GFP_FS is unset; but when tmfps swaps in, read_swap_cache_async allocates with GFP_HIGHUSER_MOVABLE regardless of the mapping_gfp_mask - hence the hang. So, pass gfp_mask down the line from shmem_getpage to shmem_swapin to swapin_readahead to read_swap_cache_async to add_to_swap_cache. Signed-off-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by:
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Hugh Dickins authored
swapin_readahead has never sat well in mm/memory.c: move it to mm/swap_state.c beside its kindred read_swap_cache_async. Why were its args in a different order? rearrange them. And since it was always followed by a read_swap_cache_async of the target page, fold that in and return struct page*. Then CONFIG_SWAP=n no longer needs valid_swaphandles and read_swap_cache_async stubs. Signed-off-by:
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Hugh Dickins authored
For three years swapin_readahead has been cluttered with fanciful CONFIG_NUMA code, advancing addr, and stepping on to the next vma at the boundary, to line up the mempolicy for each page allocation. It _might_ be a good idea to allocate swap more according to vma layout; but the fact is, that's not how we do it at all, 2.6 even less than 2.4: swap is allocated as needed for pages as they sink to the bottom of the inactive LRUs. Sometimes that may match vma layout, but not so often that it's worth going to these misleading vma->vm_next lengths: rip all that out. Originally I intended to retain the incrementation of addr, but correct its initial value: valid_swaphandles generally supplies an offset below the target addr (this is readaround rather than readahead), but addr has not been adjusted accordingly, so in the interleave case it has usually been allocating the target page from the "wrong" node (though that may not matter very much). But look at the equivalent shmem_swapin code: either by oversight or by design, though it has all the apparatus for choosing a new mempolicy per page, it uses the same idx throughout, choosing the same mempolicy and interleave node for each page of the cluster. Which is actually a much better strategy: each node has its own LRUs and its own kswapd, so if you're betting on any particular relationship between swap and node, the best bet is that nearby swap entries belong to pages from the same node - even when the mempolicy of the target page is to interleave. And examining a map of nodes corresponding to swap entries on a numa=fake system bears this out. (We could later tweak swap allocation to make it even more likely, but this patch is merely about removing cruft.) So, neither adjust nor increment addr in swapin_readahead, and then shmem_swapin can use it too; the pseudo-vma to pass policy need only be set up once per cluster, and so few fields of pvma are used, let's skip the memset - from shmem_alloc_page also. Signed-off-by:
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Ken Chen authored
Allow sticky directory mount option for hugetlbfs. This allows admin to create a shared hugetlbfs mount point for multiple users, while prevent accidental file deletion that users may step on each other. It is similiar to default tmpfs mount option, or typical option used on /tmp. Signed-off-by:
Ken Chen <kenchen@google.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <hermes@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by:
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Christoph Lameter authored
The constructor for buffer_head slabs was removed recently. We need the constructor back in slab defrag in order to insure that slab objects always have a definite state even before we allocated them. I think we mistakenly merged the removal of the constuctor into a cleanup patch. You (ie: akpm) had a test that showed that the removal of the constructor led to a small regression. The prior state makes things easier for slab defrag. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
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Christoph Lameter authored
Both slab defrag and the large blocksize patches need to ability to take refcounts on compound pages. May be useful in other places as well. Signed-off-by:
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