On Tuesday 28 June 2016 08:55:32 Michael Grzeschik wrote: > On Tue, Jun 28, 2016 at 08:18:47AM +0200, Sascha Hauer wrote: > > On Fri, Jun 24, 2016 at 12:06:01PM +0200, Markus Pargmann wrote: > > > From: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx> > > > > > > Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx> > > > Signed-off-by: Markus Pargmann <mpa@xxxxxxxxxxxxxx> > > > --- > > > common/state/backend_bucket_direct.c | 55 ++++++++++++++++++++++++++++++++++++ > > > 1 file changed, 55 insertions(+) > > > > What's the problem this patch tries to solve? > > The backend storage is writing the first correct bucket data it finds > back to each copy. Therefor every bucket got written on every boot. Even > if the content did not change. The direct backend was missing an cache > that represent the current data in the buckets. This patch adds the > cache and improves the bootup time on systems with direct bucket storage > like eeproms. I talked with Sascha. He suggested to use a separate cache that implements caching for any bucket type. That would remove all the caching code from bucket-direct and bucket-circular and make it simpler. Best Regards, Markus > > Michael > > > Sascha > > > > > > > > diff --git a/common/state/backend_bucket_direct.c b/common/state/backend_bucket_direct.c > > > index 08892f001e25..772267f6dc1d 100644 > > > --- a/common/state/backend_bucket_direct.c > > > +++ b/common/state/backend_bucket_direct.c > > > @@ -29,6 +29,10 @@ struct state_backend_storage_bucket_direct { > > > > > > int fd; > > > > > > + /* Cached data of the last read/write */ > > > + u8 *current_data; > > > + ssize_t current_data_len; > > > + > > > struct device_d *dev; > > > }; > > > > > > @@ -99,6 +103,29 @@ static int state_backend_bucket_direct_read(struct state_backend_storage_bucket > > > return 0; > > > } > > > > > > + > > > +static int state_backend_bucket_direct_fill_cache( > > > + struct state_backend_storage_bucket *bucket) > > > +{ > > > + struct state_backend_storage_bucket_direct *direct = > > > + get_bucket_direct(bucket); > > > + ssize_t read_len; > > > + uint8_t *buf; > > > + int ret; > > > + > > > + ret = state_backend_bucket_direct_read(bucket, &buf, &read_len); > > > + if (ret < 0) { > > > + dev_err(direct->dev, "Failed to read from file, %d\n", ret); > > > + free(buf); > > > + return ret; > > > + } > > > + > > > + direct->current_data = buf; > > > + direct->current_data_len = read_len; > > > + > > > + return 0; > > > +} > > > + > > > static int state_backend_bucket_direct_write(struct state_backend_storage_bucket > > > *bucket, const uint8_t * buf, > > > ssize_t len) > > > @@ -111,6 +138,11 @@ static int state_backend_bucket_direct_write(struct state_backend_storage_bucket > > > if (direct->max_size && len > direct->max_size) > > > return -E2BIG; > > > > > > + /* Nothing in cache? Then read to see what is on the device currently */ > > > + if (!direct->current_data) { > > > + state_backend_bucket_direct_fill_cache(bucket); > > > + } > > > + > > > ret = lseek(direct->fd, direct->offset, SEEK_SET); > > > if (ret < 0) { > > > dev_err(direct->dev, "Failed to seek file, %d\n", ret); > > > @@ -119,6 +151,26 @@ static int state_backend_bucket_direct_write(struct state_backend_storage_bucket > > > > > > meta.magic = direct_magic; > > > meta.written_length = len; > > > + > > > + /* > > > + * If we would write the same data that is currently on the device, we > > > + * can return successfully without writing. > > > + * Note that the cache may still be empty if the storage is empty or > > > + * errors occured. > > > + */ > > > + if (direct->current_data) { > > > + dev_dbg(direct->dev, "Comparing cached data, writing %zd bytes, cached %zd bytes\n", > > > + len, direct->current_data_len); > > > + if (len == direct->current_data_len && > > > + !memcmp(direct->current_data, buf, len)) { > > > + dev_dbg(direct->dev, "Data already on device, not writing again\n"); > > > + return ret; > > > + } else { > > > + free(direct->current_data); > > > + direct->current_data = NULL; > > > + } > > > + } > > > + > > > ret = write_full(direct->fd, &meta, sizeof(meta)); > > > if (ret < 0) { > > > dev_err(direct->dev, "Failed to write metadata to file, %d\n", ret); > > > @@ -147,6 +199,9 @@ static void state_backend_bucket_direct_free(struct > > > struct state_backend_storage_bucket_direct *direct = > > > get_bucket_direct(bucket); > > > > > > + if (direct->current_data) > > > + free(direct->current_data); > > > + > > > close(direct->fd); > > > free(direct); > > > } > > > > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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