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| author | Gerd Hoffmann <kraxel@redhat.com> | 2015-10-30 12:10:00 +0100 |
|---|---|---|
| committer | Gerd Hoffmann <kraxel@redhat.com> | 2015-11-05 09:08:41 +0100 |
| commit | 1ff36b5d4d00a4e3633eb960bf2be562f5e47dbf (patch) | |
| tree | 4534dbf57bfeaf9611baa4b1041282a48c81b138 /util/buffer.c | |
| parent | 830a9583206a051c240b74c3f688a015dc5d2967 (diff) | |
| download | qemu-1ff36b5d4d00a4e3633eb960bf2be562f5e47dbf.zip qemu-1ff36b5d4d00a4e3633eb960bf2be562f5e47dbf.tar.gz qemu-1ff36b5d4d00a4e3633eb960bf2be562f5e47dbf.tar.bz2 | |
buffer: add buffer_shrink
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1446203414-4013-6-git-send-email-kraxel@redhat.com
Diffstat (limited to 'util/buffer.c')
| -rw-r--r-- | util/buffer.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/util/buffer.c b/util/buffer.c index e8f798e..234e33d 100644 --- a/util/buffer.c +++ b/util/buffer.c @@ -20,7 +20,8 @@ #include "qemu/buffer.h" -#define BUFFER_MIN_INIT_SIZE 4096 +#define BUFFER_MIN_INIT_SIZE 4096 +#define BUFFER_MIN_SHRINK_SIZE 65536 void buffer_init(Buffer *buffer, const char *name, ...) { @@ -31,6 +32,23 @@ void buffer_init(Buffer *buffer, const char *name, ...) va_end(ap); } +void buffer_shrink(Buffer *buffer) +{ + /* + * Only shrink in case the used size is *much* smaller than the + * capacity, to avoid bumping up & down the buffers all the time. + * realloc() isn't exactly cheap ... + */ + if (buffer->offset < (buffer->capacity >> 3) && + buffer->capacity > BUFFER_MIN_SHRINK_SIZE) { + return; + } + + buffer->capacity = pow2ceil(buffer->offset); + buffer->capacity = MAX(buffer->capacity, BUFFER_MIN_SHRINK_SIZE); + buffer->buffer = g_realloc(buffer->buffer, buffer->capacity); +} + void buffer_reserve(Buffer *buffer, size_t len) { if ((buffer->capacity - buffer->offset) < len) { |