81 lines
2.3 KiB
Ruby
81 lines
2.3 KiB
Ruby
# frozen_string_literal: true
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require 'fiddle'
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module Gitlab
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module Memory
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module Jemalloc
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extend self
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STATS_FORMATS = {
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json: { options: 'J', extension: 'json' },
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text: { options: '', extension: 'txt' }
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}.freeze
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STATS_DEFAULT_FORMAT = :json
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# Return jemalloc stats as a string.
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def stats(format: STATS_DEFAULT_FORMAT)
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dump_stats(StringIO.new, format: format).string
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end
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# Streams jemalloc stats to the given IO object.
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def dump_stats(io, format: STATS_DEFAULT_FORMAT)
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verify_format!(format)
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format_settings = STATS_FORMATS[format]
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with_malloc_stats_print do |stats_print|
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write_stats(stats_print, io, format_settings)
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end
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io
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end
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private
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def verify_format!(format)
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raise "format must be one of #{STATS_FORMATS.keys}" unless STATS_FORMATS.key?(format)
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end
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def with_malloc_stats_print
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fiddle_func = malloc_stats_print
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return unless fiddle_func
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yield fiddle_func
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end
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def malloc_stats_print
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method = Fiddle::Handle.sym("malloc_stats_print")
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Fiddle::Function.new(
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method,
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# C signature:
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# void (write_cb_t *write_cb, void *cbopaque, const char *opts)
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# arg1: callback function pointer (see below)
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# arg2: pointer to cbopaque holding additional callback data; always NULL here
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# arg3: options string, affects output format (text or JSON)
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#
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# Callback signature (write_cb_t):
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# void (void *, const char *)
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# arg1: pointer to cbopaque data (see above; unused)
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# arg2: pointer to string buffer holding textual output
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[Fiddle::TYPE_VOIDP, Fiddle::TYPE_VOIDP, Fiddle::TYPE_VOIDP],
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Fiddle::TYPE_VOID
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)
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rescue Fiddle::DLError
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# This means the Fiddle::Handle to jemalloc was not open (jemalloc wasn't loaded)
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# or already closed. Eiher way, return nil.
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end
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def write_stats(stats_print, io, format)
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callback = Fiddle::Closure::BlockCaller.new(
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Fiddle::TYPE_VOID, [Fiddle::TYPE_VOIDP, Fiddle::TYPE_VOIDP]) do |_, fragment|
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io << fragment
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end
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stats_print.call(callback, nil, format[:options])
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end
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end
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end
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end
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