- 15 Apr, 2015 40 commits
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Julia Lawall authored
Return a negative error code on failure. A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ identifier ret; expression e1,e2; @@ ( if (\(ret < 0\|ret != 0\)) { ... return ret; } | ret = 0 ) ... when != ret = e1 when != &ret *if(...) { ... when != ret = e2 when forall return ret; } // </smpl> Signed-off-by:
Julia Lawall <Julia.Lawall@lip6.fr> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Acked-by:
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Sergey Senozhatsky authored
Do not perform cond_resched() before the busy compaction loop in __zs_compact(), because this loop does it when needed. Signed-off-by:
Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by:
Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by:
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Heesub Shin authored
There is no point in overriding the size class below. It causes fatal corruption on the next chunk on the 3264-bytes size class, which is the last size class that is not huge. For example, if the requested size was exactly 3264 bytes, current zsmalloc allocates and returns a chunk from the size class of 3264 bytes, not 4096. User access to this chunk may overwrite head of the next adjacent chunk. Here is the panic log captured when freelist was corrupted due to this: Kernel BUG at ffffffc00030659c [verbose debug info unavailable] Internal error: Oops - BUG: 96000006 [#1] PREEMPT SMP Modules linked in: exynos-snapshot: core register saved(CPU:5) CPUMERRSR: 0000000000000000, L2MERRSR: 0000000000000000 exynos-snapshot: context saved(CPU:5) exynos-snapshot: item - log_kevents is disabled CPU: 5 PID: 898 Comm: kswapd0 Not tainted 3.10.61-4497415-eng #1 task: ffffffc0b8783d80 ti: ffffffc0b71e8000 task.ti: ffffffc0b71e8000 PC is at obj_idx_to_offset+0x0/0x1c LR is at obj_malloc+0x44/0xe8 pc : [<ffffffc00030659c>] lr : [<ffffffc000306604>] pstate: a0000045 sp : ffffffc0b71eb790 x29: ffffffc0b71eb790 x28: ffffffc00204c000 x27: 000000000001d96f x26: 0000000000000000 x25: ffffffc098cc3500 x24: ffffffc0a13f2810 x23: ffffffc098cc3501 x22: ffffffc0a13f2800 x21: 000011e1a02006e3 x20: ffffffc0a13f2800 x19: ffffffbc02a7e000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000feb x15: 0000000000000000 x14: 00000000a01003e3 x13: 0000000000000020 x12: fffffffffffffff0 x11: ffffffc08b264000 x10: 00000000e3a01004 x9 : ffffffc08b263fea x8 : ffffffc0b1e611c0 x7 : ffffffc000307d24 x6 : 0000000000000000 x5 : 0000000000000038 x4 : 000000000000011e x3 : ffffffbc00003e90 x2 : 0000000000000cc0 x1 : 00000000d0100371 x0 : ffffffbc00003e90 Reported-by:Sooyong Suk <s.suk@samsung.com> Signed-off-by:
Heesub Shin <heesub.shin@samsung.com> Tested-by:
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Minchan Kim authored
In putback_zspage, we don't need to insert a zspage into list of zspage in size_class again to just fix fullness group. We could do directly without reinsertion so we could save some instuctions. Reported-by:
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Sergey Senozhatsky authored
A micro-optimization. Avoid additional branching and reduce (a bit) registry pressure (f.e. s_off += size; d_off += size; may be calculated twise: first for >= PAGE_SIZE check and later for offset update in "else" clause). scripts/bloat-o-meter shows some improvement add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-10 (-10) function old new delta zs_object_copy 550 540 -10 Signed-off-by:
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Sergey Senozhatsky authored
Do not synchronize rcu in zs_compact(). Neither zsmalloc not zram use rcu. Signed-off-by:
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Sergey Senozhatsky authored
Add Documentation/ABI/obsolete/sysfs-block-zram file and list obsolete and deprecated attributes there. The patch also adds additional information to zram documentation and describes the basic strategy: - the existing RW nodes will be downgraded to WO nodes (in 4.11) - deprecated RO sysfs nodes will eventually be removed (in 4.11) Users will be additionally notified about deprecated attr usage by pr_warn_once() (added to every deprecated attr _show()), as suggested by Minchan Kim. User space is advised to use zram<id>/stat, zram<id>/io_stat and zram<id>/mm_stat files. Signed-off-by:
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Sergey Senozhatsky authored
Per-device `zram<id>/mm_stat' file provides mm statistics of a particular zram device in a format similar to block layer statistics. The file consists of a single line and represents the following stats (separated by whitespace): orig_data_size compr_data_size mem_used_total mem_limit mem_used_max zero_pages num_migrated Signed-off-by: -
Sergey Senozhatsky authored
Per-device `zram<id>/io_stat' file provides accumulated I/O statistics of particular zram device in a format similar to block layer statistics. The file consists of a single line and represents the following stats (separated by whitespace): failed_reads failed_writes invalid_io notify_free Signed-off-by: -
Sergey Senozhatsky authored
Briefly describe exported device stat attrs in zram documentation. We will eventually get rid of per-stat sysfs nodes and, thus, clean up Documentation/ABI/testing/sysfs-block-zram file, which is the only source of information about device sysfs nodes. Add `num_migrated' description, since there is no independent `num_migrated' sysfs node (and no corresponding sysfs-block-zram entry), it will be exported via zram<id>/mm_stat file. At this point we can provide minimal description, because sysfs-block-zram still contains detailed information. Signed-off-by:
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Sergey Senozhatsky authored
Use bio generic_start_io_acct() and generic_end_io_acct() to account device's block layer statistics. This will let users to monitor zram activities using sysstat and similar packages/tools. Apart from the usual per-stat sysfs attr, zram IO stats are now also available in '/sys/block/zram<id>/stat' and '/proc/diskstats' files. We will slowly get rid of per-stat sysfs files. Signed-off-by:
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Sergey Senozhatsky authored
A cosmetic change. We have a new code layout and keep zram per-device sysfs store and show functions in one place. Move compact_store() to that handlers block to conform to current layout. Signed-off-by:
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Sergey Senozhatsky authored
This patch introduces rework to zram stats. We have per-stat sysfs nodes, and it makes things a bit hard to use in user space: it doesn't give an immediate stats 'snapshot', it requires user space to use more syscalls - open, read, close for every stat file, with appropriate error checks on every step, etc. First, zram now accounts block layer statistics, available in /sys/block/zram<id>/stat and /proc/diskstats files. So some new stats are available (see Documentation/block/stat.txt), besides, zram's activities now can be monitored by sysstat's iostat or similar tools. Example: cat /sys/block/zram0/stat 248 0 1984 0 251029 0 2008232 5120 0 5116 5116 Second, group currently exported on per-stat basis nodes into two categories (files): -- zram<id>/io_stat accumulates device's IO stats, that are not accounted by block layer, and contains: failed_reads failed_writes invalid_io notify_free Example: cat /sys/block/zram0/io_stat 0 0 0 652572 -- zram<id>/mm_stat accumulates zram mm stats and contains: orig_data_size compr_data_size mem_used_total mem_limit mem_used_max zero_pages num_migrated Example: cat /sys/block/zram0/mm_stat 434634752 270288572 279158784 0 579895296 15060 0 per-stat sysfs nodes are now considered to be deprecated and we plan to remove them (and clean up some of the existing stat code) in two years (as of now, there is no warning printed to syslog about deprecated stats being used). User space is advised to use the above mentioned 3 files. This patch (of 7): Remove sysfs `num_migrated' attribute. We are moving away from per-stat device attrs towards 3 stat files that will accumulate io and mm stats in a format similar to block layer statistics in /sys/block/<dev>/stat. That will be easier to use in user space, and reduce the number of syscalls needed to read zram device statistics. `num_migrated' will return back in zram<id>/mm_stat file. Signed-off-by: -
Yinghao Xie authored
Signed-off-by:
Yinghao Xie <yinghao.xie@sumsung.com> Suggested-by:
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Minchan Kim authored
Create zsmalloc doc which explains design concept and stat information. Signed-off-by:
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Minchan Kim authored
During investigating compaction, fullness information of each class is helpful for investigating how the compaction works well. With that, we could know how compaction works well more clear on each size class. Signed-off-by:
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Minchan Kim authored
We store handle on header of each allocated object so it increases the size of each object by sizeof(unsigned long). If zram stores 4096 bytes to zsmalloc(ie, bad compression), zsmalloc needs 4104B-class to add handle. However, 4104B-class has 1-pages_per_zspage so wasted size by internal fragment is 8192 - 4104, which is terrible. So this patch records the handle in page->private on such huge object(ie, pages_per_zspage == 1 && maxobj_per_zspage == 1) instead of header of each object so we could use 4096B-class, not 4104B-class. Signed-off-by:
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Minchan Kim authored
Now that zsmalloc supports compaction, zram can use it. For the first step, this patch exports compact knob via sysfs so user can do compaction via "echo 1 > /sys/block/zram0/compact". Signed-off-by:
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Minchan Kim authored
Curretly, zsmalloc regards a zspage as ZS_ALMOST_EMPTY if the zspage has under 1/4 used objects(ie, fullness_threshold_frac). It could make result in loose packing since zsmalloc migrates only ZS_ALMOST_EMPTY zspage out. This patch changes the rule so that zsmalloc makes zspage which has above 3/4 used object ZS_ALMOST_FULL so it could make tight packing. Signed-off-by:
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Minchan Kim authored
This patch provides core functions for migration of zsmalloc. Migraion policy is simple as follows. for each size class { while { src_page = get zs_page from ZS_ALMOST_EMPTY if (!src_page) break; dst_page = get zs_page from ZS_ALMOST_FULL if (!dst_page) dst_page = get zs_page from ZS_ALMOST_EMPTY if (!dst_page) break; migrate(from src_page, to dst_page); } } For migration, we need to identify which objects in zspage are allocated to migrate them out. We could know it by iterating of freed objects in a zspage because first_page of zspage keeps free objects singly-linked list but it's not efficient. Instead, this patch adds a tag(ie, OBJ_ALLOCATED_TAG) in header of each object(ie, handle) so we could check whether the object is allocated easily. This patch adds another status bit in handle to synchronize between user access through zs_map_object and migration. During migration, we cannot move objects user are using due to data coherency between old object and new object. [akpm@linux-foundation.org: zsmalloc.c needs sched.h for cond_resched()] Signed-off-by: -
Minchan Kim authored
In later patch, migration needs some part of functions in zs_malloc and zs_free so this patch factor out them. Signed-off-by:
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Minchan Kim authored
Recently, we started to use zram heavily and some of issues popped. 1) external fragmentation I got a report from Juneho Choi that fork failed although there are plenty of free pages in the system. His investigation revealed zram is one of the culprit to make heavy fragmentation so there was no more contiguous 16K page for pgd to fork in the ARM. 2) non-movable pages Other problem of zram now is that inherently, user want to use zram as swap in small memory system so they use zRAM with CMA to use memory efficiently. However, unfortunately, it doesn't work well because zRAM cannot use CMA's movable pages unless it doesn't support compaction. I got several reports about that OOM happened with zram although there are lots of swap space and free space in CMA area. 3) internal fragmentation zRAM has started support memory limitation feature to limit memory usage and I sent a patchset(https://lkml.org/lkml/2014/9/21/148) for VM to be harmonized with zram-swap to stop anonymous page reclaim if zram consumed memory up to the limit although there are free space on the swap. One problem for that direction is zram has no way to know any hole in memory space zsmalloc allocated by internal fragmentation so zram would regard swap is full although there are free space in zsmalloc. For solving the issue, zram want to trigger compaction of zsmalloc before it decides full or not. This patchset is first step to support above issues. For that, it adds indirect layer between handle and object location and supports manual compaction to solve 3th problem first of all. After this patchset got merged, next step is to make VM aware of zsmalloc compaction so that generic compaction will move zsmalloced-pages automatically in runtime. In my imaginary experiment(ie, high compress ratio data with heavy swap in/out on 8G zram-swap), data is as follows, Before = zram allocated object : 60212066 bytes zram total used: 140103680 bytes ratio: 42.98 percent MemFree: 840192 kB Compaction After = frag ratio after compaction zram allocated object : 60212066 bytes zram total used: 76185600 bytes ratio: 79.03 percent MemFree: 901932 kB Juneho reported below in his real platform with small aging. So, I think the benefit would be bigger in real aging system for a long time. - frag_ratio increased 3% (ie, higher is better) - memfree increased about 6MB - In buddy info, Normal 2^3: 4, 2^2: 1: 2^1 increased, Highmem: 2^1 21 increased frag ratio after swap fragment used : 156677 kbytes total: 166092 kbytes frag_ratio : 94 meminfo before compaction MemFree: 83724 kB Node 0, zone Normal 13642 1364 57 10 61 17 9 5 4 0 0 Node 0, zone HighMem 425 29 1 0 0 0 0 0 0 0 0 num_migrated : 23630 compaction done frag ratio after compaction used : 156673 kbytes total: 160564 kbytes frag_ratio : 97 meminfo after compaction MemFree: 89060 kB Node 0, zone Normal 14076 1544 67 14 61 17 9 5 4 0 0 Node 0, zone HighMem 863 50 1 0 0 0 0 0 0 0 0 This patchset adds more logics(about 480 lines) in zsmalloc but when I tested heavy swapin/out program, the regression for swapin/out speed is marginal because most of overheads were caused by compress/decompress and other MM reclaim stuff. This patch (of 7): Currently, handle of zsmalloc encodes object's location directly so it makes support of migration hard. This patch decouples handle and object via adding indirect layer. For that, it allocates handle dynamically and returns it to user. The handle is the address allocated by slab allocation so it's unique and we could keep object's location in the memory space allocated for handle. With it, we can change object's position without changing handle itself. Signed-off-by:
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Andrew Morton authored
mm/compaction.c:250:13: warning: 'suitable_migration_target' defined but not used [-Wunused-function] Reported-by:
Fengguang Wu <fengguang.wu@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by:
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Boaz Harrosh authored
The original dax patchset split the ext2/4_file_operations because of the two NULL splice_read/splice_write in the dax case. In the vfs if splice_read/splice_write are NULL we then call default_splice_read/write. What we do here is make generic_file_splice_read aware of IS_DAX() so the original ext2/4_file_operations can be used as is. For write it appears that iter_file_splice_write is just fine. It uses the regular f_op->write(file,..) or new_sync_write(file, ...). Signed-off-by:
Boaz Harrosh <boaz@plexistor.com> Reviewed-by:
Jan Kara <jack@suse.cz> Cc: Dave Chinner <dchinner@redhat.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by:
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Boaz Harrosh authored
From: Yigal Korman <yigal@plexistor.com> [v1] Without this patch, c/mtime is not updated correctly when mmap'ed page is first read from and then written to. A new xfstest is submitted for testing this (generic/080) [v2] Jan Kara has pointed out that if we add the sb_start/end_pagefault pair in the new pfn_mkwrite we are then fixing another bug where: A user could start writing to the page while filesystem is frozen. Signed-off-by:
Yigal Korman <yigal@plexistor.com> Signed-off-by:
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Boaz Harrosh authored
This will allow FS that uses VM_PFNMAP | VM_MIXEDMAP (no page structs) to get notified when access is a write to a read-only PFN. This can happen if we mmap() a file then first mmap-read from it to page-in a read-only PFN, than we mmap-write to the same page. We need this functionality to fix a DAX bug, where in the scenario above we fail to set ctime/mtime though we modified the file. An xfstest is attached to this patchset that shows the failure and the fix. (A DAX patch will follow) This functionality is extra important for us, because upon dirtying of a pmem page we also want to RDMA the page to a remote cluster node. We define a new pfn_mkwrite and do not reuse page_mkwrite because 1 - The name ;-) 2 - But mainly because it would take a very long and tedious audit of all page_mkwrite functions of VM_MIXEDMAP/VM_PFNMAP users. To make sure they do not now CRASH. For example current DAX code (which this is for) would crash. If we would want to reuse page_mkwrite, We will need to first patch all users, so to not-crash-on-no-page. Then enable this patch. But even if I did that I would not sleep so well at night. Adding a new vector is the safest thing to do, and is not that expensive. an extra pointer at a static function vector per driver. Also the new vector is better for performance, because else we Will call all current Kernel vectors, so to: check-ha-no-page-do-nothing and return. No need to call it from do_shared_fault because do_wp_page is called to change pte permissions anyway. Signed-off-by:Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by:
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Konstantin Khlebnikov authored
A lot of filesystems use generic_file_mmap() and filemap_fault(), f_op->mmap and vm_ops->fault aren't enough to identify filesystem. This prints file name, vm_ops->fault, f_op->mmap and a_ops->readpage (which is almost always implemented and filesystem-specific). Example: [ 23.676410] BUG: Bad page map in process sh pte:1b7e6025 pmd:19bbd067 [ 23.676887] page:ffffea00006df980 count:4 mapcount:1 mapping:ffff8800196426c0 index:0x97 [ 23.677481] flags: 0x10000000000000c(referenced|uptodate) [ 23.677896] page dumped because: bad pte [ 23.678205] addr:00007f52fcb17000 vm_flags:00000075 anon_vma: (null) mapping:ffff8800196426c0 index:97 [ 23.678922] file:libc-2.19.so fault:filemap_fault mmap:generic_file_readonly_mmap readpage:v9fs_vfs_readpage [akpm@linux-foundation.org: use pr_alert, per Kirill] Signed-off-by:
Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Sasha Levin <sasha.levin@oracle.com> Acked-by:
Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by:
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Andrey Ryabinin authored
Mempools keep allocated objects in reserved for situations when ordinary allocation may not be possible to satisfy. These objects shouldn't be accessed before they leave the pool. This patch poison elements when get into the pool and unpoison when they leave it. This will let KASan to detect use-after-free of mempool's elements. Signed-off-by:
Andrey Ryabinin <a.ryabinin@samsung.com> Tested-by:
David Rientjes <rientjes@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Chernenkov <drcheren@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by:
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Andrew Morton authored
Like EXPORT_SYMBOL(): the positioning communicates that the macro pertains to the immediately preceding function. Cc: Dmitry Safonov <d.safonov@partner.samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Stefan Strogin <stefan.strogin@gmail.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Pintu Kumar <pintu.k@samsung.com> Cc: Weijie Yang <weijie.yang@samsung.com> Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Cc: Vyacheslav Tyrtov <v.tyrtov@samsung.com> Cc: Aleksei Mateosian <a.mateosian@samsung.com> Signed-off-by:
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Dmitry Safonov authored
Here are two functions that provide interface to compute/get used size and size of biggest free chunk in cma region. Add that information to debugfs. [akpm@linux-foundation.org: move debug code from cma.c into cma_debug.c] [stefan.strogin@gmail.com: move code from cma_get_used() and cma_get_maxchunk() to cma_used_get() and cma_maxchunk_get()] Signed-off-by:
Dmitry Safonov <d.safonov@partner.samsung.com> Signed-off-by:
Stefan Strogin <stefan.strogin@gmail.com> Acked-by:
Michal Nazarewicz <mina86@mina86.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Pintu Kumar <pintu.k@samsung.com> Cc: Weijie Yang <weijie.yang@samsung.com> Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Cc: Vyacheslav Tyrtov <v.tyrtov@samsung.com> Cc: Aleksei Mateosian <a.mateosian@samsung.com> Signed-off-by:
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Kirill A. Shutemov authored
Few trivial cleanups: - no need to call set_recommended_min_free_kbytes() from late_initcall() -- start_khugepaged() calls it; - no need to call set_recommended_min_free_kbytes() from start_khugepaged() if khugepaged is not started; - there isn't much point in running start_khugepaged() if we've just set transparent_hugepage_flags to zero; - start_khugepaged() is misnamed -- it also used to stop the thread; Signed-off-by:
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Kirill A. Shutemov authored
Most-used page->mapping helper -- page_mapping() -- has already uninlined. Let's uninline also page_rmapping() and page_anon_vma(). It saves us depending on configuration around 400 bytes in text: text data bss dec hex filename 660318 99254 410000 1169572 11d8a4 mm/built-in.o-before 659854 99254 410000 1169108 11d6d4 mm/built-in.o I also tried to make code a bit more clean. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
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Stefan Strogin authored
Add trace events for cma_alloc() and cma_release(). The cma_alloc tracepoint is used both for successful and failed allocations, in case of allocation failure pfn=-1UL is stored and printed. Signed-off-by:
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Borislav Petkov authored
Flip the flag test so that it is the simplest. No functional change, just a small readability improvement: No code changed: # arch/x86/kernel/sys_x86_64.o: text data bss dec hex filename 1551 24 0 1575 627 sys_x86_64.o.before 1551 24 0 1575 627 sys_x86_64.o.after md5: 70708d1b1ad35cc891118a69dc1a63f9 sys_x86_64.o.before.asm 70708d1b1ad35cc891118a69dc1a63f9 sys_x86_64.o.after.asm Signed-off-by:
Borislav Petkov <bp@suse.de> Signed-off-by:
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Alexander Kuleshov authored
memblock_reserve() calls memblock_reserve_region() which prints debugging information if 'memblock=debug' was passed on the command line. This patch adds the same behaviour, but for memblock_add function(). [akpm@linux-foundation.org: s/memblock_memory/memblock_add/ in message] Signed-off-by:
Alexander Kuleshov <kuleshovmail@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Philipp Hachtmann <phacht@linux.vnet.ibm.com> Cc: Fabian Frederick <fabf@skynet.be> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Emil Medve <Emilian.Medve@freescale.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by:
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Naoya Horiguchi authored
Now we have an easy access to hugepages' activeness, so existing helpers to get the information can be cleaned up. [akpm@linux-foundation.org: s/PageHugeActive/page_huge_active/] Signed-off-by:
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Hugh Dickins <hughd@google.com> Reviewed-by:
Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by:
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Naoya Horiguchi authored
We are not safe from calling isolate_huge_page() on a hugepage concurrently, which can make the victim hugepage in invalid state and results in BUG_ON(). The root problem of this is that we don't have any information on struct page (so easily accessible) about hugepages' activeness. Note that hugepages' activeness means just being linked to hstate->hugepage_activelist, which is not the same as normal pages' activeness represented by PageActive flag. Normal pages are isolated by isolate_lru_page() which prechecks PageLRU before isolation, so let's do similarly for hugetlb with a new paeg_huge_active(). set/clear_page_huge_active() should be called within hugetlb_lock. But hugetlb_cow() and hugetlb_no_page() don't do this, being justified because in these functions set_page_huge_active() is called right after the hugepage is allocated and no other thread tries to isolate it. [akpm@linux-foundation.org: s/PageHugeActive/page_huge_active/, make it return bool] [fengguang.wu@intel.com: set_page_huge_active() can be static] Signed-off-by:
Fengguang Wu <fengguang.wu@intel.com> Signed-off-by:
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Naoya Horiguchi authored
__put_compound_page() calls __page_cache_release() to do some freeing work, but it's obviously for thps, not for hugetlb. We don't care because PageLRU is always cleared and page->mem_cgroup is always NULL for hugetlb. But it's not correct and has potential risks, so let's make it conditional. Signed-off-by:
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Rasmus Villemoes authored
The creators of the C language gave us the while keyword. Let's use that instead of synthesizing it from if+goto. Made possible by 6597d783 ("mm/mmap.c: replace find_vma_prepare() with clearer find_vma_links()"). [akpm@linux-foundation.org: fix 80-col overflows] Signed-off-by:
Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Hugh Dickins <hughd@google.com> Signed-off-by:
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David Rientjes authored
When MAP_HUGETLB memory is unmapped, the length must be hugepage aligned, otherwise it fails with -EINVAL. All tests currently behave correctly, but it's better to explcitly test the return value for completeness and document the requirement, especially if users copy map_hugetlb.c as a sample implementation. Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Signed-off-by:
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