Re: [U-Boot] [PATCH] fw_setenv: avoid writing environment when nothing has changed
On 2018-09-24 09:42, Alex Kiernan wrote: > On Wed, Sep 5, 2018 at 8:23 PM Rasmus Villemoes > wrote: >> >> In the case where one deletes an already-non-existing variable, or sets >> a variable to the value it already has, there is no point in writing the >> environment back, thus reducing wear on the underlying storage >> device. >> >> Signed-off-by: Rasmus Villemoes > > If you were running with a redundant env, and you were trying to sync > both copies, wouldn't you want a non-changing write to happen? Hm, probably, yes. But I'd still like to avoid it if they are already in sync, so perhaps I could just add if (memcmp(environment.data, redundant->data, ENV_SIZE)) environment.dirty = 1; after reading in the second copy [using that environment.data at that point is still ((struct env_image_redundant *)addr0)->data ]. Rasmus ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
Re: [U-Boot] [PATCH] fw_setenv: avoid writing environment when nothing has changed
On Mon, 2018-09-24 at 08:42 +0100, Alex Kiernan wrote: > CAUTION: This email originated from outside of the organization. Do not click > links or open attachments unless you recognize the sender and know the > content is safe. > > > On Wed, Sep 5, 2018 at 8:23 PM Rasmus Villemoes > wrote: > > > > In the case where one deletes an already-non-existing variable, or sets > > a variable to the value it already has, there is no point in writing the > > environment back, thus reducing wear on the underlying storage > > device. > > > > Signed-off-by: Rasmus Villemoes > > If you were running with a redundant env, and you were trying to sync > both copies, wouldn't you want a non-changing write to happen? That is a valid point, I have sometimes used this property to make sure I have a valid env. in both copies. Jocke ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
Re: [U-Boot] [PATCH] fw_setenv: avoid writing environment when nothing has changed
On Wed, Sep 5, 2018 at 8:23 PM Rasmus Villemoes
wrote:
>
> In the case where one deletes an already-non-existing variable, or sets
> a variable to the value it already has, there is no point in writing the
> environment back, thus reducing wear on the underlying storage
> device.
>
> Signed-off-by: Rasmus Villemoes
If you were running with a redundant env, and you were trying to sync
both copies, wouldn't you want a non-changing write to happen?
> ---
> tools/env/fw_env.c | 10 +-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/tools/env/fw_env.c b/tools/env/fw_env.c
> index a5d75958e1..87aaa15198 100644
> --- a/tools/env/fw_env.c
> +++ b/tools/env/fw_env.c
> @@ -110,6 +110,7 @@ struct environment {
> unsigned char *flags;
> char *data;
> enum flag_scheme flag_scheme;
> + int dirty;
> };
>
> static struct environment environment = {
> @@ -508,6 +509,9 @@ int fw_env_flush(struct env_opts *opts)
> if (!opts)
> opts = _opts;
>
> + if (!environment.dirty)
> + return 0;
> +
> /*
> * Update CRC
> */
> @@ -553,7 +557,8 @@ int fw_env_write(char *name, char *value)
>
> deleting = (oldval && !(value && strlen(value)));
> creating = (!oldval && (value && strlen(value)));
> - overwriting = (oldval && (value && strlen(value)));
> + overwriting = (oldval && (value && strlen(value) &&
> + strcmp(oldval, value)));
>
> /* check for permission */
> if (deleting) {
> @@ -593,6 +598,7 @@ int fw_env_write(char *name, char *value)
> /* Nothing to do */
> return 0;
>
> + environment.dirty = 1;
> if (deleting || overwriting) {
> if (*++nxt == '\0') {
> *env = '\0';
> @@ -1441,6 +1447,7 @@ int fw_env_open(struct env_opts *opts)
> "Warning: Bad CRC, using default
> environment\n");
> memcpy(environment.data, default_environment,
>sizeof(default_environment));
> + environment.dirty = 1;
> }
> } else {
> flag0 = *environment.flags;
> @@ -1503,6 +1510,7 @@ int fw_env_open(struct env_opts *opts)
> "Warning: Bad CRC, using default
> environment\n");
> memcpy(environment.data, default_environment,
>sizeof(default_environment));
> + environment.dirty = 1;
> dev_current = 0;
> } else {
> switch (environment.flag_scheme) {
> --
> 2.16.4
>
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--
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Re: [U-Boot] [PATCH] fw_setenv: avoid writing environment when nothing has changed
Hi On Mon., 24 Sep. 2018, 8:19 am Rasmus Villemoes, wrote: > On 2018-09-05 21:22, Rasmus Villemoes wrote: > > In the case where one deletes an already-non-existing variable, or sets > > a variable to the value it already has, there is no point in writing the > > environment back, thus reducing wear on the underlying storage > > device. > > ping > Sorry I will give a try and make sense in my use cases Michael > ___ > U-Boot mailing list > U-Boot@lists.denx.de > https://lists.denx.de/listinfo/u-boot > ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
Re: [U-Boot] [PATCH] fw_setenv: avoid writing environment when nothing has changed
On 2018-09-05 21:22, Rasmus Villemoes wrote: > In the case where one deletes an already-non-existing variable, or sets > a variable to the value it already has, there is no point in writing the > environment back, thus reducing wear on the underlying storage > device. ping ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
[U-Boot] [PATCH] fw_setenv: avoid writing environment when nothing has changed
In the case where one deletes an already-non-existing variable, or sets
a variable to the value it already has, there is no point in writing the
environment back, thus reducing wear on the underlying storage
device.
Signed-off-by: Rasmus Villemoes
---
tools/env/fw_env.c | 10 +-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/tools/env/fw_env.c b/tools/env/fw_env.c
index a5d75958e1..87aaa15198 100644
--- a/tools/env/fw_env.c
+++ b/tools/env/fw_env.c
@@ -110,6 +110,7 @@ struct environment {
unsigned char *flags;
char *data;
enum flag_scheme flag_scheme;
+ int dirty;
};
static struct environment environment = {
@@ -508,6 +509,9 @@ int fw_env_flush(struct env_opts *opts)
if (!opts)
opts = _opts;
+ if (!environment.dirty)
+ return 0;
+
/*
* Update CRC
*/
@@ -553,7 +557,8 @@ int fw_env_write(char *name, char *value)
deleting = (oldval && !(value && strlen(value)));
creating = (!oldval && (value && strlen(value)));
- overwriting = (oldval && (value && strlen(value)));
+ overwriting = (oldval && (value && strlen(value) &&
+ strcmp(oldval, value)));
/* check for permission */
if (deleting) {
@@ -593,6 +598,7 @@ int fw_env_write(char *name, char *value)
/* Nothing to do */
return 0;
+ environment.dirty = 1;
if (deleting || overwriting) {
if (*++nxt == '\0') {
*env = '\0';
@@ -1441,6 +1447,7 @@ int fw_env_open(struct env_opts *opts)
"Warning: Bad CRC, using default
environment\n");
memcpy(environment.data, default_environment,
sizeof(default_environment));
+ environment.dirty = 1;
}
} else {
flag0 = *environment.flags;
@@ -1503,6 +1510,7 @@ int fw_env_open(struct env_opts *opts)
"Warning: Bad CRC, using default
environment\n");
memcpy(environment.data, default_environment,
sizeof(default_environment));
+ environment.dirty = 1;
dev_current = 0;
} else {
switch (environment.flag_scheme) {
--
2.16.4
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