mirror of
https://github.com/seaweedfs/seaweedfs.git
synced 2026-07-26 01:53:02 +00:00
Chris LuandGitHub
e1fa4ec756
* perf(cache): drop OS page cache after disk cache reads After reading from the on-disk chunk cache, advise the kernel via FADV_DONTNEED to release the corresponding page cache pages. This prevents double-caching the same data in both user-space and kernel page caches, freeing RAM for other uses on systems with large disk caches. * fix(cache): guard dropReadCache against zero length and invalid fd A zero-length fadvise is interpreted as "to end of file" on Linux, which would inadvertently drop the page cache for the entire remainder of the cache volume. Also check fd >= 0 to avoid unnecessary syscalls when the backend file is closed. * perf(cache): only apply FADV_DONTNEED for reads >= 1 MiB For small needle reads the syscall overhead outweighs the memory savings, and the kernel page cache is more beneficial for warm data. Restrict fadvise to reads of at least 1 MiB where the freed page cache is meaningful.
38 lines
796 B
Go
38 lines
796 B
Go
//go:build linux
|
|
|
|
package util
|
|
|
|
import (
|
|
"os"
|
|
"testing"
|
|
)
|
|
|
|
func TestDropOSPageCache(t *testing.T) {
|
|
f, err := os.CreateTemp("", "fadvise_test")
|
|
if err != nil {
|
|
t.Fatalf("failed to create temp file: %v", err)
|
|
}
|
|
defer os.Remove(f.Name())
|
|
defer f.Close()
|
|
|
|
data := make([]byte, 4096)
|
|
for i := range data {
|
|
data[i] = byte(i % 256)
|
|
}
|
|
if _, err := f.Write(data); err != nil {
|
|
t.Fatalf("failed to write test data: %v", err)
|
|
}
|
|
|
|
// Read the data back to populate page cache
|
|
buf := make([]byte, 4096)
|
|
if _, err := f.ReadAt(buf, 0); err != nil {
|
|
t.Fatalf("failed to read test data: %v", err)
|
|
}
|
|
|
|
// Call DropOSPageCache and verify no error
|
|
fd := int(f.Fd())
|
|
if err := DropOSPageCache(fd, 0, int64(len(data))); err != nil {
|
|
t.Errorf("DropOSPageCache returned error: %v", err)
|
|
}
|
|
}
|