bcda0042e
Denys Vlasenko
2010-03-19
Subject
libbb/copyfd.c: don't mmap a largish buffer if we only want to copy a few kb
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Commit Diff GitHub →
libbb/copyfd.c+3 -0
| @@ -22,6 +22,8 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size) | |
| char *buffer; | |
| int buffer_size; | |
| + | if (size > 0 && size <= 4 * 1024) |
| + | goto use_small_buf; |
| /* We want page-aligned buffer, just in case kernel is clever | |
| * and can do page-aligned io more efficiently */ | |
| buffer = mmap(NULL, CONFIG_FEATURE_COPYBUF_KB * 1024, | |
| @@ -30,6 +32,7 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size) | |
| /* ignored: */ -1, 0); | |
| buffer_size = CONFIG_FEATURE_COPYBUF_KB * 1024; | |
| if (buffer == MAP_FAILED) { | |
| + | use_small_buf: |
| buffer = alloca(4 * 1024); | |
| buffer_size = 4 * 1024; | |
| } | |