- 07 Aug, 2014 40 commits
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Mel Gorman authored
The fair zone allocation policy round-robins allocations between zones within a node to avoid age inversion problems during reclaim. If the first allocation fails, the batch counts are reset and a second attempt made before entering the slow path. One assumption made with this scheme is that batches expire at roughly the same time and the resets each time are justified. This assumption does not hold when zones reach their low watermark as the batches will be consumed at uneven rates. Allocation failure due to watermark depletion result in additional zonelist scans for the reset and another watermark check before hitting the slowpath. On UMA, the benefit is negligible -- around 0.25%. On 4-socket NUMA machine it's variable due to the variability of measuring overhead with the vmstat changes. The system CPU overhead comparison looks like 3.16.0-rc3 3.16.0-rc3 3.16.0-rc3 vanilla vmstat-v5 lowercost-v5 User 746.94 774.56 802.00 System 65336.22 32847.27 40852.33 Elapsed 27553.52 27415.04 27368.46 However it is worth noting that the overall benchmark still completed faster and intuitively it makes sense to take as few passes as possible through the zonelists. Signed-off-by:Mel Gorman <mgorman@suse.de> Acked-by:
Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Mel Gorman authored
The purpose of numa_zonelist_order=zone is to preserve lower zones for use with 32-bit devices. If locality is preferred then the numa_zonelist_order=node policy should be used. Unfortunately, the fair zone allocation policy overrides this by skipping zones on remote nodes until the lower one is found. While this makes sense from a page aging and performance perspective, it breaks the expected zonelist policy. This patch restores the expected behaviour for zone-list ordering. Signed-off-by:
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Mel Gorman authored
When kswapd is awake reclaiming, the per-cpu stat thresholds are lowered to get more accurate counts to avoid breaching watermarks. This threshold update iterates over all possible CPUs which is unnecessary. Only online CPUs need to be updated. If a new CPU is onlined, refresh_zone_stat_thresholds() will set the thresholds correctly. Signed-off-by:
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Mel Gorman authored
zone->pages_scanned is a write-intensive cache line during page reclaim and it's also updated during page free. Move the counter into vmstat to take advantage of the per-cpu updates and do not update it in the free paths unless necessary. On a small UMA machine running tiobench the difference is marginal. On a 4-node machine the overhead is more noticable. Note that automatic NUMA balancing was disabled for this test as otherwise the system CPU overhead is unpredictable. 3.16.0-rc3 3.16.0-rc3 3.16.0-rc3 vanillarearrange-v5 vmstat-v5 User 746.94 759.78 774.56 System 65336.22 58350.98 32847.27 Elapsed 27553.52 27282.02 27415.04 Note that the overhead reduction will vary depending on where exactly pages are allocated and freed. Signed-off-by: -
Mel Gorman authored
The arrangement of struct zone has changed over time and now it has reached the point where there is some inappropriate sharing going on. On x86-64 for example o The zone->node field is shared with the zone lock and zone->node is accessed frequently from the page allocator due to the fair zone allocation policy. o span_seqlock is almost never used by shares a line with free_area o Some zone statistics share a cache line with the LRU lock so reclaim-intensive and allocator-intensive workloads can bounce the cache line on a stat update This patch rearranges struct zone to put read-only and read-mostly fields together and then splits the page allocator intensive fields, the zone statistics and the page reclaim intensive fields into their own cache lines. Note that the type of lowmem_reserve changes due to the watermark calculations being signed and avoiding a signed/unsigned conversion there. On the test configuration I used the overall size of struct zone shrunk by one cache line. On smaller machines, this is not likely to be noticable. However, on a 4-node NUMA machine running tiobench the system CPU overhead is reduced by this patch. 3.16.0-rc3 3.16.0-rc3 vanillarearrange-v5r9 User 746.94 759.78 System 65336.22 58350.98 Elapsed 27553.52 27282.02 Signed-off-by: -
Mel Gorman authored
This was formerly the series "Improve sequential read throughput" which noted some major differences in performance of tiobench since 3.0. While there are a number of factors, two that dominated were the introduction of the fair zone allocation policy and changes to CFQ. The behaviour of fair zone allocation policy makes more sense than tiobench as a benchmark and CFQ defaults were not changed due to insufficient benchmarking. This series is what's left. It's one functional fix to the fair zone allocation policy when used on NUMA machines and a reduction of overhead in general. tiobench was used for the comparison despite its flaws as an IO benchmark as in this case we are primarily interested in the overhead of page allocator and page reclaim activity. On UMA, it makes little difference to overhead 3.16.0-rc3 3.16.0-rc3 vanilla lowercost-v5 User 383.61 386.77 System 403.83 401.74 Elapsed 5411.50 5413.11 On a 4-socket NUMA machine it's a bit more noticable 3.16.0-rc3 3.16.0-rc3 vanilla lowercost-v5 User 746.94 802.00 System 65336.22 40852.33 Elapsed 27553.52 27368.46 This patch (of 6): The LRU insertion and activate tracepoints take PFN as a parameter forcing the overhead to the caller. Move the overhead to the tracepoint fast-assign method to ensure the cost is only incurred when the tracepoint is active. Signed-off-by: -
Chen Yucong authored
Until now, the reporting from trace-vmscan-postprocess.pl is not very useful because we cannot directly use this script for checking the file/anon ratio of scanning. This patch aims to report respectively the number of file/anon pages which were scanned/reclaimed by kswapd or direct-reclaim. Sample output is usually something like the following. Summary Direct reclaims: 8823 Direct reclaim pages scanned: 2438797 Direct reclaim file pages scanned: 1315200 Direct reclaim anon pages scanned: 1123597 Direct reclaim pages reclaimed: 446139 Direct reclaim file pages reclaimed: 378668 Direct reclaim anon pages reclaimed: 67471 Direct reclaim write file sync I/O: 0 Direct reclaim write anon sync I/O: 0 Direct reclaim write file async I/O: 0 Direct reclaim write anon async I/O: 4240 Wake kswapd requests: 122310 Time stalled direct reclaim: 13.78 seconds Kswapd wakeups: 25817 Kswapd pages scanned: 170779115 Kswapd file pages scanned: 162725123 Kswapd anon pages scanned: 8053992 Kswapd pages reclaimed: 129065738 Kswapd file pages reclaimed: 128500930 Kswapd anon pages reclaimed: 564808 Kswapd reclaim write file sync I/O: 0 Kswapd reclaim write anon sync I/O: 0 Kswapd reclaim write file async I/O: 36 Kswapd reclaim write anon async I/O: 730730 Time kswapd awake: 1015.50 seconds Signed-off-by:
Chen Yucong <slaoub@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
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Wang Sheng-Hui authored
vm_total_pages is calculated by nr_free_pagecache_pages(), which counts the number of pages which are beyond the high watermark within all zones. So vm_total_pages is not equal to total number of pages which the VM controls. Signed-off-by:
Wang Sheng-Hui <shhuiw@gmail.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
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Cyrill Gorcunov authored
Otherwise we may not notice that pte was softdirty because pte_mksoft_dirty helper _returns_ new pte but doesn't modify the argument. In case if page fault happend on dirty filemapping the newly created pte may loose softdirty bit thus if a userspace program is tracking memory changes with help of a memory tracker (CONFIG_MEM_SOFT_DIRTY) it might miss modification of a memory page (which in worts case may lead to data inconsistency). Signed-off-by:
Cyrill Gorcunov <gorcunov@openvz.org> Acked-by:
Pavel Emelyanov <xemul@parallels.com> Signed-off-by:
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Yasuaki Ishimatsu authored
When limiting memory by mem= and ACPI DSDT table has PNP0C80, firmware_map_entrys of same memory range are allocated and memmap X sysfses which have same memory range are created as follows: # cat /sys/firmware/memmap/0/* 0x407ffffffff 0x40000000000 System RAM # cat /sys/firmware/memmap/33/* 0x407ffffffff 0x40000000000 System RAM # cat /sys/firmware/memmap/35/* 0x407ffffffff 0x40000000000 System RAM In this case, when hot-removing memory, kernel panic occurs, showing following call trace: BUG: unable to handle kernel paging request at 00000001003e000b IP: sysfs_open_file+0x46/0x2b0 PGD 203a89fe067 PUD 0 Oops: 0000 [#1] SMP ... Call Trace: do_dentry_open+0x1ef/0x2a0 finish_open+0x31/0x40 do_last+0x57c/0x1220 path_openat+0xc2/0x4c0 do_filp_open+0x4b/0xb0 do_sys_open+0xf3/0x1f0 SyS_open+0x1e/0x20 system_call_fastpath+0x16/0x1b The problem occurs as follows: When calling e820_reserve_resources(), firmware_map_entrys of all e820 memory map are allocated. And all firmware_map_entrys is added map_entries list as follows: map_entries -> +--- entry A --------+ -> ... | start 0x407ffffffff| | end 0x40000000000| | type System RAM | +--------------------+ After that, if ACPI DSDT table has PNP0C80 and the memory range is limited by mem=, the PNP0C80 is hot-added. Then firmware_map_entry of PNP0C80 is allocated and added map_entries list as follows: map_entries -> +--- entry A --------+ -> ... -> +--- entry B --------+ | start 0x407ffffffff| | start 0x407ffffffff| | end 0x40000000000| | end 0x40000000000| | type System RAM | | type System RAM | +--------------------+ +--------------------+ Then memmap 0 sysfs for entry B is created. After that, firmware_memmap_init() creates memmap sysfses of all firmware_map_entrys in map_entries list. As a result, memmap 33 sysfs for entry A and memmap 35 sysfs for entry B are created. But kobject of entry B has been used by memmap 0 sysfs. So when creating memmap 35 sysfs, the kobject is broken. If hot-removing memory, memmap 0 sysfs is destroyed and kobject of memmap 0 sysfs is freed. But the kobject can be accessed via memmap 35 sysfs. So when open memmap 35 sysfs, kernel panic occurs. This patch checks whether there is firmware_map_entry of same memory range in map_entries list and don't allocate firmware_map_entry of same memroy range. Signed-off-by:Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: Toshi Kani <toshi.kani@hp.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
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Yasuaki Ishimatsu authored
firmware_map_add_hotplug() calls firmware_map_find_entry_bootmem() to get free firmware_map_entry. But end arguments is not correct. So firmware_map_find_entry_bootmem() cannot not find firmware_map_entry. The patch passes the correct end argument to firmware_map_find_entry_bootmem(). Signed-off-by:
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WANG Chao authored
Currently map_vm_area() takes (struct page *** pages) as third argument, and after mapping, it moves (*pages) to point to (*pages + nr_mappped_pages). It looks like this kind of increment is useless to its caller these days. The callers don't care about the increments and actually they're trying to avoid this by passing another copy to map_vm_area(). The caller can always guarantee all the pages can be mapped into vm_area as specified in first argument and the caller only cares about whether map_vm_area() fails or not. This patch cleans up the pointer movement in map_vm_area() and updates its callers accordingly. Signed-off-by:
WANG Chao <chaowang@redhat.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by:
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Jerome Marchand authored
Commit 71e3aac0 ("thp: transparent hugepage core") adds copy_pte_range prototype to huge_mm.h. I'm not sure why (or if) this function have been used outside of memory.c, but it currently isn't. This patch makes copy_pte_range() static again. Signed-off-by:
Jerome Marchand <jmarchan@redhat.com> Acked-by:
David Rientjes <rientjes@google.com> Signed-off-by:
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David Rientjes authored
They are unnecessary: "zero" can be used in place of "hugetlb_zero" and passing extra2 == NULL is equivalent to infinity. Signed-off-by:
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by:
Luiz Capitulino <lcapitulino@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by:
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David Rientjes authored
Three different interfaces alter the maximum number of hugepages for an hstate: - /proc/sys/vm/nr_hugepages for global number of hugepages of the default hstate, - /sys/kernel/mm/hugepages/hugepages-X/nr_hugepages for global number of hugepages for a specific hstate, and - /sys/kernel/mm/hugepages/hugepages-X/nr_hugepages/mempolicy for number of hugepages for a specific hstate over the set of allowed nodes. Generalize the code so that a single function handles all of these writes instead of duplicating the code in two different functions. This decreases the number of lines of code, but also reduces the size of .text by about half a percent since set_max_huge_pages() can be inlined. Signed-off-by:
Davidlohr Bueso <davidlohr@hp.com> Signed-off-by:
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Andi Kleen authored
When a hwpoison page is locked it could change state due to parallel modifications. The original compound page can be torn down and then this 4k page becomes part of a differently-size compound page is is a standalone regular page. Check after the lock if the page is still the same compound page. We could go back, grab the new head page and try again but it should be quite rare, so I thought this was safest. A retry loop would be more difficult to test and may have more side effects. The hwpoison code by design only tries to handle cases that are reasonably common in workloads, as visible in page-flags. I'm not really that concerned about handling this (likely rare case), just not crashing on it. Signed-off-by:
Andi Kleen <ak@linux.intel.com> Acked-by:
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Davidlohr Bueso authored
When returning from hugetlb_cow(), we always (1) put back the refcount for each referenced page -- always 'old', and 'new' if allocation was successful. And (2) retake the page table lock right before returning, as the callers expects. This logic can be simplified and encapsulated, as proposed in this patch. In addition to cleaner code, we also shave a few bytes off the instruction text: text data bss dec hex filename 28399 462 41328 70189 1122d mm/hugetlb.o-baseline 28367 462 41328 70157 1120d mm/hugetlb.o-patched Passes libhugetlbfs testcases. Signed-off-by:
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Davidlohr Bueso authored
This function always returns 1, thus no need to check return value in hugetlb_cow(). By doing so, we can get rid of the unnecessary WARN_ON call. While this logic perhaps existed as a way of identifying future unmap_ref_private() mishandling, reality is it serves no apparent purpose. Signed-off-by:
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Hugh Dickins authored
Do we really need an exported alias for __SetPageReferenced()? Its callers better know what they're doing, in which case the page would not be already marked referenced. Kill init_page_accessed(), just __SetPageReferenced() inline. Signed-off-by:
Hugh Dickins <hughd@google.com> Acked-by:
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Fabian Frederick authored
Fix checkpatch warning: "WARNING: debugfs_remove_recursive(NULL) is safe this check is probably not required" Signed-off-by:
Fabian Frederick <fabf@skynet.be> Acked-by:
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Rafael Aquini authored
Historically, we exported shared pages to userspace via sysinfo(2) sharedram and /proc/meminfo's "MemShared" fields. With the advent of tmpfs, from kernel v2.4 onward, that old way for accounting shared mem was deemed inaccurate and we started to export a hard-coded 0 for sysinfo.sharedram. Later on, during the 2.6 timeframe, "MemShared" got re-introduced to /proc/meminfo re-branded as "Shmem", but we're still reporting sysinfo.sharedmem as that old hard-coded zero, which makes the "shared memory" report inconsistent across interfaces. This patch leverages the addition of explicit accounting for pages used by shmem/tmpfs -- "4b02108a mm: oom analysis: add shmem vmstat" -- in order to make the users of sysinfo(2) and si_meminfo*() friends aware of that vmstat entry and make them report it consistently across the interfaces, as well to make sysinfo(2) returned data consistent with our current API documentation states. Signed-off-by:
Rafael Aquini <aquini@redhat.com> Acked-by:
Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by:
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Konstantin Khlebnikov authored
Print a warning (if CONFIG_DEBUG_VM=y) when memory commitment becomes too negative. This shouldn't happen any more - the previous two patches fixed the committed_as underflow issues. [akpm@linux-foundation.org: use VM_WARN_ONCE, per Dave] Signed-off-by:
Konstantin Khlebnikov <koct9i@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by:
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Konstantin Khlebnikov authored
A shared anonymous mapping created without MAP_NORESERVE holds memory reservation for whole range of shmem segment. Usually there is no way to change its size, but /proc/<pid>/map_files/... (available if CONFIG_CHECKPOINT_RESTORE=y) allows that. This patch adjusts the memory reservation in shmem_setattr(). Signed-off-by:
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Konstantin Khlebnikov authored
If __shmem_file_setup() fails on struct file allocation it uncharges memory commitment twice: first by shmem_unacct_size() and second time implicitly in shmem_evict_inode() when it kills the newly created inode. This patch removes shmem_unacct_size() from error path if the inode was already there. Signed-off-by:
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Andrew Morton authored
It was missing... Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by:
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David Rientjes authored
tmp_mask in the __vmalloc_area_node() iteration never changes so it can be moved into function scope and marked with const. This causes the movl and orl to only be done once per call rather than area->nr_pages times. nested_gfp can also be marked const. Signed-off-by:
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Eric Dumazet authored
It is not uncommon on busy servers to get stuck hundred of ms in vmalloc() calls (like file descriptor expansions). Add a cond_resched() to __vmalloc_area_node() to be gentle to other tasks. [akpm@linux-foundation.org: only do it for __GFP_WAIT, per David] Signed-off-by:
Eric Dumazet <edumazet@google.com> Cc: Hugh Dickins <hughd@google.com> Acked-by:
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Wang Sheng-Hui authored
Currently, we have more filesystems supporting fallocate, e.g ext4/btrfs. Remove the outdated comment for madvise_remove. Signed-off-by:
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Max Asbock authored
The mm_migrate_pages trace event reports a reason for the migration, typically as a symbolic string. The exception is the reason MR_NUMA_MISPLACED for which it just displays the numeric value: mm_migrate_pages: nr_succeeded=1 nr_failed=0 mode=MIGRATE_ASYNC reason=0x5 This patch makes the output consistent by introducing a string value for MR_NUMA_MISPLACED. The event is then reported as: mm_migrate_pages: nr_succeeded=1 nr_failed=0 mode=MIGRATE_ASYNC reason=numa_misplaced Signed-off-by:
Max Asbock <masbock@linux.vnet.ibm.com> Acked-by:
Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Acked-by:
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Johannes Weiner authored
Reorder the members by input and output, then turn the individual integers for may_writepage, may_unmap, may_swap, compaction_ready, hibernation_mode into bit fields to save stack space: +72/-296 -224 kswapd 104 176 +72 try_to_free_pages 80 56 -24 try_to_free_mem_cgroup_pages 80 56 -24 shrink_all_memory 88 64 -24 reclaim_clean_pages_from_list 168 144 -24 mem_cgroup_shrink_node_zone 104 80 -24 __zone_reclaim 176 152 -24 balance_pgdat 152 - -152 Signed-off-by:
Michal Hocko <mhocko@suse.cz> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Rik van Riel <riel@redhat.com> Acked-by:
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Johannes Weiner authored
Swappiness is determined for each scanned memcg individually in shrink_zone() and is not a parameter that applies throughout the reclaim scan. Move it out of struct scan_control to prevent accidental use of a stale value. Signed-off-by:
Minchan Kim <minchan@kernel.org> Signed-off-by:
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Johannes Weiner authored
Direct reclaim currently calls shrink_zones() to reclaim all members of a zonelist, and if that wasn't successful it does another pass through the same zonelist to check overall reclaimability. Just check reclaimability in shrink_zones() directly and propagate the result through the return value. Then remove all_unreclaimable(). Signed-off-by:
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Johannes Weiner authored
Page reclaim for a higher-order page runs until compaction is ready, then aborts and signals this situation through the return value of shrink_zones(). This is an oddly specific signal to encode in the return value of shrink_zones(), though, and can be quite confusing. Introduce sc->compaction_ready and signal the compactability of the zones out-of-band to free up the return value of shrink_zones() for actual zone reclaimability. Signed-off-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Michal Hocko <mhocko@suse.cz> Acked-by:
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Johannes Weiner authored
shrink_zones() has a special branch to skip the all_unreclaimable() check during hibernation, because a frozen kswapd can't mark a zone unreclaimable. But ever since commit 6e543d57 ("mm: vmscan: fix do_try_to_free_pages() livelock"), determining a zone to be unreclaimable is done by directly looking at its scan history and no longer relies on kswapd setting the per-zone flag. Remove this branch and let shrink_zones() check the reclaimability of the target zones regardless of hibernation state. Signed-off-by:
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Wang Nan authored
In original code, zone_movable_is_highmem() assumes ZONE_MOVABLE not highmem if CONFIG_HAVE_MEMBLOCK_NODE_MAP is not set. In online_pages, it extracts pages from the previous zone before ZONE_MOVABLE. Which is logically inconsistent: If HAVE_MEMBLOCK_NODE_MAP is turned off but HIGHMEM is on, zone_movable_is_highmem() makes movable zone not highmem, but online_pages() extracts pages from ZONE_HIGHMEM. This inconsistency doesn't cause real problem currently, because all architectures support online_pages also have HAVE_MEMBLOCK_NODE_MAP. However, fixing it makes code clear, and also helps futher coding. Signed-off-by:
Wang Nan <wangnan0@huawei.com> Cc: Zhang Zhen <zhangzhen@huawei.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Jiang Liu <liuj97@gmail.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Yinghai Lu <yinghai@kernel.org> Signed-off-by:
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Zhang Zhen authored
Use the newer and more pleasant kstrtoull() to replace simple_strtoull(), because simple_strtoull() is marked for obsoletion. Signed-off-by:
Zhang Zhen <zhenzhang.zhang@huawei.com> Acked-by:
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Johannes Weiner authored
Kmem page charging and uncharging is serialized by means of exclusive access to the page. Do not take the page_cgroup lock and don't set pc->flags atomically. Signed-off-by:
Vladimir Davydov <vdavydov@parallels.com> Cc: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by:
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Johannes Weiner authored
There is a write barrier between setting pc->mem_cgroup and PageCgroupUsed, which was added to allow LRU operations to lookup the memcg LRU list of a page without acquiring the page_cgroup lock. But ever since commit 38c5d72f ("memcg: simplify LRU handling by new rule"), pages are ensured to be off-LRU while charging, so nobody else is changing LRU state while pc->mem_cgroup is being written, and there are no read barriers anymore. Remove the unnecessary write barrier. Signed-off-by:
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Johannes Weiner authored
Due to an old optimization to keep expensive res_counter changes at a minimum, the root_mem_cgroup res_counter is never charged; there is no limit at that level anyway, and any statistics can be generated on demand by summing up the counters of all other cgroups. However, with per-cpu charge caches, res_counter operations do not even show up in profiles anymore, so this optimization is no longer necessary. Remove it to simplify the code. Signed-off-by:
Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by:
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Johannes Weiner authored
When mem_cgroup_try_charge() returns -EINTR, it bypassed the charge to the root memcg. But move precharging does not catch this and treats this case as if no charge had happened, thus leaking a charge against root. Because of an old optimization, the root memcg's res_counter is not actually charged right now, but it's still an imbalance and subsequent patches will charge the root memcg again. Catch those bypasses to the root memcg and properly cancel them before giving up the move. Signed-off-by:
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