- 29 May, 2012 40 commits
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Andrew Morton authored
- make pageflag_names[] const - remove null termination of pageflag_names[] Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Gavin Shan <shangw@linux.vnet.ibm.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Johannes Weiner authored
String tables with names of enum items are always prone to go out of sync with the enums themselves. Ensure during compile time that the name table of page flags has the same size as the page flags enum. Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Cc: Gavin Shan <shangw@linux.vnet.ibm.com> Signed-off-by:
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Gavin Shan authored
The array pageflag_names[] does conversion from page flags into their corresponding names so that a meaningful representation of the corresponding page flag can be printed. This mechanism is used while dumping page frames. However, the array missed PG_compound_lock. So the PG_compound_lock page flag would be printed as a digital number instead of a meaningful string. The patch fixes that and prints "compound_lock" for the PG_compound_lock page flag. Signed-off-by:
Gavin Shan <shangw@linux.vnet.ibm.com> Acked-by:
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Cong Wang authored
It is better to define readahead(2) in mm/readahead.c than in mm/filemap.c. Signed-off-by:
Cong Wang <xiyou.wangcong@gmail.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Hugh Dickins authored
It's quite easy for tmpfs to scan the radix_tree to support llseek's new SEEK_DATA and SEEK_HOLE options: so add them while the minutiae are still on my mind (in particular, the !PageUptodate-ness of pages fallocated but still unwritten). But I don't know who actually uses SEEK_DATA or SEEK_HOLE, and whether it would be of any use to them on tmpfs. This code adds 92 lines and 752 bytes on x86_64 - is that bloat or worthwhile? [akpm@linux-foundation.org: fix warning with CONFIG_TMPFS=n] Signed-off-by:
Hugh Dickins <hughd@google.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Josef Bacik <josef@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Andreas Dilger <adilger@dilger.ca> Cc: Dave Chinner <david@fromorbit.com> Cc: Marco Stornelli <marco.stornelli@gmail.com> Cc: Jeff liu <jeff.liu@oracle.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by:
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Hugh Dickins authored
As it stands, a large fallocate() on tmpfs is liable to fill memory with pages, freed on failure except when they run into swap, at which point they become fixed into the file despite the failure. That feels quite wrong, to be consuming resources precisely when they're in short supply. Go the other way instead: shmem_fallocate() indicate the range it has fallocated to shmem_writepage(), keeping count of pages it's allocating; shmem_writepage() reactivate instead of swapping out pages fallocated by this syscall (but happily swap out those from earlier occasions), keeping count; shmem_fallocate() compare counts and give up once the reactivated pages have started to coming back to writepage (approximately: some zones would in fact recycle faster than others). This is a little unusual, but works well: although we could consider the failure to swap as a bug, and fix it later with SWAP_MAP_FALLOC handling added in swapfile.c and memcontrol.c, I doubt that we shall ever want to. (If there's no swap, an over-large fallocate() on tmpfs is limited in the same way as writing: stopped by rlimit, or by tmpfs mount size if that was set sensibly, or by __vm_enough_memory() heuristics if OVERCOMMIT_GUESS or OVERCOMMIT_NEVER. If OVERCOMMIT_ALWAYS, then it is liable to OOM-kill others as writing would, but stops and frees if interrupted.) Now that everything is freed on failure, we can then skip updating ctime. Signed-off-by:
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Hugh Dickins authored
In the previous episode, we left the already-fallocated pages attached to the file when shmem_fallocate() fails part way through. Now try to do better, by extending the earlier optimization of !Uptodate pages (then always under page lock) to !Uptodate pages (outside of page lock), representing fallocated pages. And don't waste time clearing them at the time of fallocate(), leave that until later if necessary. Adapt shmem_truncate_range() to shmem_undo_range(), so that a failing fallocate can recognize and remove precisely those !Uptodate allocations which it added (and were not independently allocated by racing tasks). But unless we start playing with swapfile.c and memcontrol.c too, once one of our fallocated pages reaches shmem_writepage(), we do then have to instantiate it as an ordinarily allocated page, before swapping out. This is unsatisfactory, but improved in the next episode. Signed-off-by:
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Hugh Dickins authored
The systemd plumbers expressed a wish that tmpfs support preallocation. Cong Wang wrote a patch, but several kernel guys expressed scepticism: https://lkml.org/lkml/2011/11/18/137 Christoph Hellwig: What for exactly? Please explain why preallocating on tmpfs would make any sense. Kay Sievers: To be able to safely use mmap(), regarding SIGBUS, on files on the /dev/shm filesystem. The glibc fallback loop for -ENOSYS [or -EOPNOTSUPP] on fallocate is just ugly. Hugh Dickins: If tmpfs is going to support fallocate(FALLOC_FL_PUNCH_HOLE), it would seem perverse to permit the deallocation but fail the allocation. Christoph Hellwig: Agreed. Now that we do have shmem_fallocate() for hole-punching, plumb in basic support for preallocation mode too. It's fairly straightforward (though quite a few details needed attention), except for when it fails part way through. What a pity that fallocate(2) was not specified to return the length allocated, permitting short fallocations! As it is, when it fails part way through, we ought to free what has just been allocated by this system call; but must be very sure not to free any allocated earlier, or any allocated by racing accesses (not all excluded by i_mutex). But we cannot distinguish them: so in this patch simply leak allocations on partial failure (they will be freed later if the file is removed). An attractive alternative approach would have been for fallocate() not to allocate pages at all, but note reservations by entries in the radix-tree. But that would give less assurance, and, critically, would be hard to fit with mem cgroups (who owns the reservations?): allocating pages lets fallocate() behave in just the same way as write(). Based-on-patch-by:
Cong Wang <amwang@redhat.com> Signed-off-by:
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Hugh Dickins authored
Remove vmtruncate_range(), and remove the truncate_range method from struct inode_operations: only tmpfs ever supported it, and tmpfs has now converted over to using the fallocate method of file_operations. Update Documentation accordingly, adding (setlease and) fallocate lines. And while we're in mm.h, remove duplicate declarations of shmem_lock() and shmem_file_setup(): everyone is now using the ones in shmem_fs.h. Based-on-patch-by:
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Hugh Dickins authored
Now tmpfs supports hole-punching via fallocate(), switch madvise_remove() to use do_fallocate() instead of vmtruncate_range(): which extends madvise(,,MADV_REMOVE) support from tmpfs to ext4, ocfs2 and xfs. There is one more user of vmtruncate_range() in our tree, staging/android's ashmem_shrink(): convert it to use do_fallocate() too (but if its unpinned areas are already unmapped - I don't know - then it would do better to use shmem_truncate_range() directly). Based-on-patch-by:
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Hugh Dickins authored
tmpfs has supported hole-punching since 2.6.16, via madvise(,,MADV_REMOVE). But nowadays fallocate(,FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE,,) is the agreed way to punch holes. So add shmem_fallocate() to support that, and tweak shmem_truncate_range() to support partial pages at both the beginning and end of range (never needed for madvise, which demands rounded addr and rounds up length). Based-on-patch-by:
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Hugh Dickins authored
Nick proposed years ago that tmpfs should avoid clearing its pages where write will overwrite them with new data, as ramfs has long done. But I messed it up and just got bad data. Tried again recently, it works fine. Here's time output for writing 4GiB 16 times on this Core i5 laptop: before: real 0m21.169s user 0m0.028s sys 0m21.057s real 0m21.382s user 0m0.016s sys 0m21.289s real 0m21.311s user 0m0.020s sys 0m21.217s after: real 0m18.273s user 0m0.032s sys 0m18.165s real 0m18.354s user 0m0.020s sys 0m18.265s real 0m18.440s user 0m0.032s sys 0m18.337s ramfs: real 0m16.860s user 0m0.028s sys 0m16.765s real 0m17.382s user 0m0.040s sys 0m17.273s real 0m17.133s user 0m0.044s sys 0m17.021s Yes, I have done perf reports, but they need more explanation than they deserve: in summary, clear_page vanishes, its cache loading shifts into copy_user_generic_unrolled; shmem_getpage_gfp goes down, and surprisingly mark_page_accessed goes way up - I think because they are respectively where the cache gets to be reloaded after being purged by clear or copy. Suggested-by:Nick Piggin <npiggin@gmail.com> Signed-off-by:
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Hugh Dickins authored
Let tmpfs into the NOSEC optimization (avoiding file_remove_suid() overhead on most common writes): set MS_NOSEC on its superblocks. Signed-off-by:
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Hugh Dickins authored
The GMA500 GPU driver uses GEM shmem objects, but with a new twist: the backing RAM has to be below 4GB. Not a problem while the boards supported only 4GB: but now Intel's D2700MUD boards support 8GB, and their GMA3600 is managed by the GMA500 driver. shmem/tmpfs has never pretended to support hardware restrictions on the backing memory, but it might have appeared to do so before v3.1, and even now it works fine until a page is swapped out then back in. When read_cache_page_gfp() supplied a freshly allocated page for copy, that compensated for whatever choice might have been made by earlier swapin readahead; but swapoff was likely to destroy the illusion. We'd like to continue to support GMA500, so now add a new shmem_should_replace_page() check on the zone when about to move a page from swapcache to filecache (in swapin and swapoff cases), with shmem_replace_page() to allocate and substitute a suitable page (given gma500/gem.c's mapping_set_gfp_mask GFP_KERNEL | __GFP_DMA32). This does involve a minor extension to mem_cgroup_replace_page_cache() (the page may or may not have already been charged); and I've removed a comment and call to mem_cgroup_uncharge_cache_page(), which in fact is always a no-op while PageSwapCache. Also removed optimization of an unlikely path in shmem_getpage_gfp(), now that we need to check PageSwapCache more carefully (a racing caller might already have made the copy). And at one point shmem_unuse_inode() needs to use the hitherto private page_swapcount(), to guard against racing with inode eviction. It would make sense to extend shmem_should_replace_page(), to cover cpuset and NUMA mempolicy restrictions too, but set that aside for now: needs a cleanup of shmem mempolicy handling, and more testing, and ought to handle swap faults in do_swap_page() as well as shmem. Signed-off-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Stephane Marchesin <marcheu@chromium.org> Cc: Andi Kleen <andi@firstfloor.org> Cc: Dave Airlie <airlied@gmail.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Rob Clark <rob.clark@linaro.org> Signed-off-by:
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Bartlomiej Zolnierkiewicz authored
When MIGRATE_UNMOVABLE pages are freed from MIGRATE_UNMOVABLE type pageblock (and some MIGRATE_MOVABLE pages are left in it) waiting until an allocation takes ownership of the block may take too long. The type of the pageblock remains unchanged so the pageblock cannot be used as a migration target during compaction. Fix it by: * Adding enum compact_mode (COMPACT_ASYNC_[MOVABLE,UNMOVABLE], and COMPACT_SYNC) and then converting sync field in struct compact_control to use it. * Adding nr_pageblocks_skipped field to struct compact_control and tracking how many destination pageblocks were of MIGRATE_UNMOVABLE type. If COMPACT_ASYNC_MOVABLE mode compaction ran fully in try_to_compact_pages() (COMPACT_COMPLETE) it implies that there is not a suitable page for allocation. In this case then check how if there were enough MIGRATE_UNMOVABLE pageblocks to try a second pass in COMPACT_ASYNC_UNMOVABLE mode. * Scanning the MIGRATE_UNMOVABLE pageblocks (during COMPACT_SYNC and COMPACT_ASYNC_UNMOVABLE compaction modes) and building a count based on finding PageBuddy pages, page_count(page) == 0 or PageLRU pages. If all pages within the MIGRATE_UNMOVABLE pageblock are in one of those three sets change the whole pageblock type to MIGRATE_MOVABLE. My particular test case (on a ARM EXYNOS4 device with 512 MiB, which means 131072 standard 4KiB pages in 'Normal' zone) is to: - allocate 120000 pages for kernel's usage - free every second page (60000 pages) of memory just allocated - allocate and use 60000 pages from user space - free remaining 60000 pages of kernel memory (now we have fragmented memory occupied mostly by user space pages) - try to allocate 100 order-9 (2048 KiB) pages for kernel's usage The results: - with compaction disabled I get 11 successful allocations - with compaction enabled - 14 successful allocations - with this patch I'm able to get all 100 successful allocations NOTE: If we can make kswapd aware of order-0 request during compaction, we can enhance kswapd with changing mode to COMPACT_ASYNC_FULL (COMPACT_ASYNC_MOVABLE + COMPACT_ASYNC_UNMOVABLE). Please see the following thread: http://marc.info/?l=linux-mm&m=133552069417068&w=2 [minchan@kernel.org: minor cleanups] Cc: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by:
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by:
Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by:
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Johannes Weiner authored
alloc_bootmem_section() derives allocation area constraints from the specified sparsemem section. This is a bit specific for a generic memory allocator like bootmem, though, so move it over to sparsemem. As __alloc_bootmem_node_nopanic() already retries failed allocations with relaxed area constraints, the fallback code in sparsemem.c can be removed and the code becomes a bit more compact overall. [akpm@linux-foundation.org: fix build] Signed-off-by:
Tejun Heo <tj@kernel.org> Acked-by:
David S. Miller <davem@davemloft.net> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Gavin Shan <shangw@linux.vnet.ibm.com> Signed-off-by:
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Johannes Weiner authored
Pass down the node descriptor instead of the more specific bootmem node descriptor down the call stack, like nobootmem does, when there is no good reason for the two to be different. Signed-off-by:
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Johannes Weiner authored
While the panicking node-specific allocation function tries to satisfy node+goal, goal, node, anywhere, the non-panicking function still does node+goal, goal, anywhere. Make it simpler: define the panicking version in terms of the non-panicking one, like the node-agnostic interface, so they always behave the same way apart from how to deal with allocation failure. Signed-off-by:
Yinghai Lu <yinghai@kernel.org> Acked-by:
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Johannes Weiner authored
__alloc_bootmem_node and __alloc_bootmem_low_node documentation claims the functions panic on allocation failure. Do it. Signed-off-by:
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Johannes Weiner authored
While the panicking node-specific allocation function tries to satisfy node+goal, goal, node, anywhere, the non-panicking function still does node+goal, goal, anywhere. Make it simpler: define the panicking version in terms of the non-panicking one, like the node-agnostic interface, so they always behave the same way apart from how to deal with allocation failure. Signed-off-by:
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Johannes Weiner authored
Match the nobootmem version of __alloc_bootmem_node. Try to satisfy both the node and the goal, then just the goal, then just the node, then allocate anywhere before panicking. Signed-off-by:
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Johannes Weiner authored
Matching the desired goal to the right node is one thing, dropping the goal when it can not be satisfied is another. Split this into separate functions so that subsequent patches can use the node-finding but drop and handle the goal fallback on their own terms. Signed-off-by:
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Johannes Weiner authored
Callsites need to provide a bootmem_data_t *, make the naming more descriptive. Signed-off-by:
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Johannes Weiner authored
When bootmem releases an unaligned BITS_PER_LONG pages chunk of memory to the page allocator, it checks the bitmap if there are still unreserved pages in the chunk (set bits), but also if the offset in the chunk indicates BITS_PER_LONG loop iterations already. But since the consulted bitmap is only a one-word-excerpt of the full per-node bitmap, there can not be more than BITS_PER_LONG bits set in it. The additional offset check is unnecessary. Signed-off-by:
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Gavin Shan authored
When bootmem releases an unaligned chunk of memory at the beginning of a node to the page allocator, it iterates from that unaligned PFN but checks an aligned word of the page bitmap. The checked bits do not correspond to the PFNs and, as a result, reserved pages can be freed. Properly shift the bitmap word so that the lowest bit corresponds to the starting PFN before entering the freeing loop. This bug has been around since commit 41546c17 ("bootmem: clean up free_all_bootmem_core") (2.6.27) without known reports. Signed-off-by:
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Andrew Morton authored
This has always been broken: one version takes an unsigned int and the other version takes no arguments. This bug was hidden because one version of set_pageblock_order() was a macro which doesn't evaluate its argument. Simplify it all and remove pageblock_default_order() altogether. Reported-by:
rajman mekaco <rajman.mekaco@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by:
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Alex Shi authored
When transparent_hugepage_enabled() is used outside mm/, such as in arch/x86/xx/tlb.c: + if (!cpu_has_invlpg || vma->vm_flags & VM_HUGETLB + || transparent_hugepage_enabled(vma)) { + flush_tlb_mm(vma->vm_mm); is_vma_temporary_stack() isn't referenced in huge_mm.h, so it has compile errors: arch/x86/mm/tlb.c: In function `flush_tlb_range': arch/x86/mm/tlb.c:324:4: error: implicit declaration of function `is_vma_temporary_stack' [-Werror=implicit-function-declaration] Since is_vma_temporay_stack() is just used in rmap.c and huge_memory.c, it is better to move it to huge_mm.h from rmap.h to avoid such errors. Signed-off-by:Alex Shi <alex.shi@intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by:
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Ulrich Drepper authored
Compiling page-type.c with a recent compiler produces many warnings, mostly related to signed/unsigned comparisons. This patch cleans up most of them. One remaining warning is about an unused parameter. The <compiler.h> file doesn't define a __unused macro (or the like) yet. This can be addressed later. Signed-off-by:
Ulrich Drepper <drepper@gmail.com> Acked-by:
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by:
Fengguang Wu <fengguang.wu@intel.com> Signed-off-by:
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Ulrich Drepper authored
Programs using /proc/kpageflags need to know about the various flags. The <linux/kernel-page-flags.h> provides them and the comments in the file indicate that it is supposed to be used by user-level code. But the file is not installed. Install the headers and mark the unstable flags as out-of-bounds. The page-type tool is also adjusted to not duplicate the definitions Signed-off-by:
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Bjorn Helgaas authored
Print physical address info in a style consistent with the %pR style used elsewhere in the kernel. For example: -Zone PFN ranges: +Zone ranges: - DMA32 0x00000010 -> 0x00100000 + DMA32 [mem 0x00010000-0xffffffff] - Normal 0x00100000 -> 0x01080000 + Normal [mem 0x100000000-0x107fffffff] Signed-off-by:Bjorn Helgaas <bhelgaas@google.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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Bjorn Helgaas authored
Print swiotlb info in a style consistent with the %pR style used elsewhere in the kernel. For example: -Placing 64MB software IO TLB between ffff88007a662000 - ffff88007e662000 -software IO TLB at phys 0x7a662000 - 0x7e662000 +software IO TLB [mem 0x7a662000-0x7e661fff] (64MB) mapped at [ffff88007a662000-ffff88007e661fff] Signed-off-by: -
Bjorn Helgaas authored
Print physical address info in a style consistent with the %pR style used elsewhere in the kernel. For example: -found SMP MP-table at [ffff8800000fce90] fce90 +found SMP MP-table at [mem 0x000fce90-0x000fce9f] mapped at [ffff8800000fce90] -initial memory mapped : 0 - 20000000 +initial memory mapped: [mem 0x00000000-0x1fffffff] -Base memory trampoline at [ffff88000009c000] 9c000 size 8192 +Base memory trampoline [mem 0x0009c000-0x0009dfff] mapped at [ffff88000009c000] -SRAT: Node 0 PXM 0 0-80000000 +SRAT: Node 0 PXM 0 [mem 0x00000000-0x7fffffff] Signed-off-by: -
Bjorn Helgaas authored
Print physical address info in a style consistent with the %pR style used elsewhere in the kernel. For example: -BIOS-provided physical RAM map: +e820: BIOS-provided physical RAM map: - BIOS-e820: 0000000000000100 - 000000000009e000 (usable) +BIOS-e820: [mem 0x0000000000000100-0x000000000009dfff] usable -Allocating PCI resources starting at 90000000 (gap: 90000000:6ed1c000) +e820: [mem 0x90000000-0xfed1bfff] available for PCI devices -reserve RAM buffer: 000000000009e000 - 000000000009ffff +e820: reserve RAM buffer [mem 0x0009e000-0x0009ffff] Signed-off-by: -
Konstantin Khlebnikov authored
Even if CONFIG_DEBUG_VM=n gcc genereates code for some VM_BUG_ON() for example VM_BUG_ON(!PageCompound(page) || !PageHead(page)); in do_huge_pmd_wp_page() generates 114 bytes of code. But they mostly disappears when I split this VM_BUG_ON into two: -VM_BUG_ON(!PageCompound(page) || !PageHead(page)); +VM_BUG_ON(!PageCompound(page)); +VM_BUG_ON(!PageHead(page)); weird... but anyway after this patch code disappears completely. add/remove: 0/0 grow/shrink: 7/97 up/down: 135/-1784 (-1649) Signed-off-by:
Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by:
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Konstantin Khlebnikov authored
Sometimes we want to check some expressions correctness at compile time. "(void)(e);" or "if (e);" can be dangerous if the expression has side-effects, and gcc sometimes generates a lot of code, even if the expression has no effect. This patch introduces macro BUILD_BUG_ON_INVALID() for such checks, it forces a compilation error if expression is invalid without any extra code. [Cast to "long" required because sizeof does not work for bit-fields.] Signed-off-by:
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Christopher Yeoh authored
Add a Kconfig option to allow people who don't want cross memory attach to not have it included in their build. Signed-off-by:
Chris Yeoh <yeohc@au1.ibm.com> Signed-off-by:
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Johannes Weiner authored
The hierarchical versions of per-memcg counters in memory.stat are all calculated the same way and are all named total_<counter>. Documenting the pattern is easier for maintenance than listing each counter twice. Signed-off-by:
Michal Hocko <mhocko@suse.cz> Acked-by:
Ying Han <yinghan@google.com> Randy Dunlap <rdunlap@xenotime.net> Acked-by:
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David Rientjes authored
mm->page_table_lock is hotly contested for page fault tests and isn't necessary to do mem_cgroup_uncharge_page() in do_huge_pmd_wp_page(). Signed-off-by:
David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by:
Andrea Arcangeli <aarcange@redhat.com> Signed-off-by:
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Ying Han authored
Andrew pointed out that the is_mlocked_vma() is misnamed. A function with name like that would expect bool return and no side-effects. Since it is called on the fault path for new page, rename it in this patch. Signed-off-by:
Rik van Riel <riel@redhat.com> Acked-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com> Reviewed-by:
Minchan Kim <minchan@kernel.org> [akpm@linux-foundation.org: s/mlock_vma_newpage/mlock_vma_newpage/, per Minchan] Signed-off-by:
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Johannes Weiner authored
The rmap walker checking page table references has historically ignored references from VMAs that were not part of the memcg that was being reclaimed during memcg hard limit reclaim. When transitioning global reclaim to memcg hierarchy reclaim, I missed that bit and now references from outside a memcg are ignored even during global reclaim. Reverting back to traditional behaviour - count all references during global reclaim and only mind references of the memcg being reclaimed during limit reclaim would be one option. However, the more generic idea is to ignore references exactly then when they are outside the hierarchy that is currently under reclaim; because only then will their reclamation be of any use to help the pressure situation. It makes no sense to ignore references from a sibling memcg and then evict a page that will be immediately refaulted by that sibling which contributes to the same usage of the common ancestor under reclaim. The solution: make the rmap walker ignore references from VMAs that are not part of the hierarchy that is being reclaimed. Flat limit reclaim will stay the same, hierarchical limit reclaim will mind the references only to pages that the hierarchy owns. Global reclaim, since it reclaims from all memcgs, will be fixed to regard all references. [akpm@linux-foundation.org: name the args in the declaration] Signed-off-by:
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