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copy: Set copy buffer size based on total physical memory

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This should increase memory efficiency for very small computers such as embedded systems.
This commit is contained in:
Andrei 2024-06-27 17:34:00 -07:00
parent d108198f39
commit 7ba6fb6816
1 changed files with 29 additions and 5 deletions
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34
src/shared/copy.c
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@ -21,6 +21,7 @@
#include "fileio.h"
#include "fs-util.h"
#include "io-util.h"
#include "limits-util.h"
#include "macro.h"
#include "missing_fs.h"
#include "missing_syscall.h"
@ -41,9 +42,6 @@
#include "user-util.h"
#include "xattr-util.h"
/* If we copy via a userspace buffer, size it to 64K */
#define COPY_BUFFER_SIZE (64U*U64_KB)
/* If a byte progress function is specified during copying, never try to copy more than 1M, so that we can
* reasonably call the progress function still */
#define PROGRESS_STEP_SIZE (1U*U64_MB)
@ -53,6 +51,32 @@
* case of bind mount cycles and suchlike. */
#define COPY_DEPTH_MAX 2048U
static uint64_t copy_buffer_size(void) {
/* If we copy via a userspace buffer, try to find a reasonable size for the copy buffer proportional
to the total physical memory of the system */
static uint64_t size = 0;
if (size == 0) {
uint64_t mem = physical_memory();
if (mem <= 128U*U64_MB)
size = 8U * U64_KB;
else if (mem <= 256U*U64_MB)
size = 12U * U64_KB;
else if (mem <= 512U*U64_MB)
size = 24U * U64_KB;
else if (mem <= 2U*U64_GB)
size = 32U * U64_KB;
else
size = 64U * U64_KB;
}
return size;
}
static ssize_t try_copy_file_range(
int fd_in, loff_t *off_in,
int fd_out, loff_t *off_out,
@ -460,7 +484,7 @@ int copy_bytes_full(
/* As a fallback just copy bits by hand */
{
uint8_t buf[MIN(m, COPY_BUFFER_SIZE)], *p = buf;
uint8_t buf[MIN(m, copy_buffer_size())], *p = buf;
ssize_t z;
n = read(fdf, buf, sizeof buf);
@ -503,7 +527,7 @@ int copy_bytes_full(
copied_total += n;
/* Disable sendfile() in case we are getting too close to it's SSIZE_MAX-offset limit */
if (copied_total > SSIZE_MAX - COPY_BUFFER_SIZE)
if (copied_total > SSIZE_MAX - copy_buffer_size())
try_sendfile = false;
if (progress) {