4c1392296
Denis Vlasenko
2007-12-02
Subject
Introduce FEATURE_COPYBUF_KB. People who want smaller stack at any cost may use it to reduce cp's stack usage (FEATURE_COPYBUF_KB=1). Desktop people may get faster copy of big files (FEATURE_COPYBUF_KB=32 is ~30% faster than 4kb)
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libbb/Config.in+10 -0
| @@ -110,6 +110,16 @@ config FEATURE_EDITING_FANCY_PROMPT | |
| Setting this option allows for prompts to use things like \w and | |
| \$ and escape codes. | |
| + | config FEATURE_COPYBUF_KB |
| + | int "Copy buffer size, in kilobytes" |
| + | range 1 1024 |
| + | default 4 |
| + | help |
| + | Size of buffer used by cp, mv, install etc. |
| + | Buffers which are 4 kb or less will be allocated on stack. |
| + | Bigger buffers will be allocated with mmap, with fallback to 4 kb |
| + | stack buffer if mmap fails. |
| + | |
| config MONOTONIC_SYSCALL | |
| bool "Use clock_gettime(CLOCK_MONOTONIC) syscall" | |
| default y | |
libbb/copyfd.c+24 -8
| @@ -9,31 +9,42 @@ | |
| #include "libbb.h" | |
| - | #if BUFSIZ < 4096 |
| - | #undef BUFSIZ |
| - | #define BUFSIZ 4096 |
| - | #endif |
| - | |
| /* Used by NOFORK applets (e.g. cat) - must not use xmalloc */ | |
| static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size) | |
| { | |
| int status = -1; | |
| off_t total = 0; | |
| - | char buffer[BUFSIZ]; |
| + | #if CONFIG_FEATURE_COPYBUF_KB <= 4 |
| + | char buffer[CONFIG_FEATURE_COPYBUF_KB * 1024]; |
| + | enum { buffer_size = sizeof(buffer) }; |
| + | #else |
| + | char *buffer; |
| + | int buffer_size; |
| + | |
| + | buffer = mmap(NULL, CONFIG_FEATURE_COPYBUF_KB * 1024, |
| + | PROT_READ | PROT_WRITE, |
| + | MAP_PRIVATE | MAP_ANON, |
| + | /* ignored: */ -1, 0); |
| + | buffer_size = CONFIG_FEATURE_COPYBUF_KB * 1024; |
| + | if (buffer == MAP_FAILED) { |
| + | buffer = alloca(4 * 1024); |
| + | buffer_size = 4 * 1024; |
| + | } |
| + | #endif |
| if (src_fd < 0) | |
| goto out; | |
| if (!size) { | |
| - | size = BUFSIZ; |
| + | size = buffer_size; |
| status = 1; /* copy until eof */ | |
| } | |
| while (1) { | |
| ssize_t rd; | |
| - | rd = safe_read(src_fd, buffer, size > BUFSIZ ? BUFSIZ : size); |
| + | rd = safe_read(src_fd, buffer, size > buffer_size ? buffer_size : size); |
| if (!rd) { /* eof - all done */ | |
| status = 0; | |
| @@ -62,6 +73,11 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size) | |
| } | |
| } | |
| out: | |
| + | |
| + | #if CONFIG_FEATURE_COPYBUF_KB > 4 |
| + | if (buffer_size != 4 * 1024) |
| + | munmap(buffer, buffer_size); |
| + | #endif |
| return status ? -1 : total; | |
| } | |