b363709c11
This change brings in changes at multiple places - Reuse buffers at almost all locations ranging from rpc, fs, xl, checksum etc. - Change caching behavior to disable itself under low memory conditions i.e < 8GB of RAM. - Only objects cached are of size 1/10th the size of the cache for example if 4GB is the cache size the maximum object size which will be cached is going to be 400MB. This change is an optimization to cache more objects rather than few larger objects. - If object cache is enabled default GC percent has been reduced to 20% in lieu with newly found behavior of GC. If the cache utilization reaches 75% of the maximum value GC percent is reduced to 10% to make GC more aggressive. - Do not use *bytes.Buffer* due to its growth requirements. For every allocation *bytes.Buffer* allocates an additional buffer for its internal purposes. This is undesirable for us, so implemented a new cappedWriter which is capped to a desired size, beyond this all writes rejected. Possible fix for #3403.
51 lines
1.5 KiB
Go
51 lines
1.5 KiB
Go
/*
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* Minio Cloud Storage, (C) 2016 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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// Package objcache implements in memory caching methods.
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package objcache
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// Used for adding entry to the object cache.
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// Implements io.WriteCloser
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type cappedWriter struct {
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offset int64
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cap int64
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buffer []byte
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onClose func() error
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}
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// Write implements a limited writer, returns error.
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// if the writes go beyond allocated size.
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func (c *cappedWriter) Write(b []byte) (n int, err error) {
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if c.offset+int64(len(b)) > c.cap {
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return 0, ErrExcessData
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}
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n = copy(c.buffer[int(c.offset):int(c.offset)+len(b)], b)
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c.offset = c.offset + int64(n)
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return n, nil
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}
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// Reset relinquishes the allocated underlying buffer.
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func (c *cappedWriter) Reset() {
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c.buffer = nil
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}
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// On close, onClose() is called which checks if all object contents
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// have been written so that it can save the buffer to the cache.
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func (c cappedWriter) Close() (err error) {
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return c.onClose()
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}
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