On Wed, 14 Jul 2010, Dmitry Monakhov wrote:
> Lukas Czerner <lczerner@xxxxxxxxxx> writes:
>
> > Walk through each allocation group and trim all free extents. It can be
> > invoked through TRIM ioctl on the file system. The main idea is to
> > provide a way to trim the whole file system if needed, since some SSD's
> > may suffer from performance loss after the whole device was filled (it
> > does not mean that fs is full!).
> >
> > It search fro free extents in each allocation group. When the free
> > extent is found, blocks are marked as used and then trimmed. Afterwards
> > these blocks are marked as free in per-group bitmap.
> Looks ok, except two small notes:
> 1) trim_fs is a time consuming operation and we have to add
> condresced, and signal_pending checks to allow user to interrupt
> cmd if necessery. See patch attached.
Hi, Dimitry
thanks for your patch! Although I have one question:
for (group = 0; group < ngroups; group++) {
- int err;
-
- err = ext4_mb_load_buddy(sb, group, &e4b);
- if (err) {
+ ret = ext4_mb_load_buddy(sb, group, &e4b);
+ if (ret) {
ext4_error(sb, "Error in loading buddy "
"information for %u", group);
- continue;
+ break;
}
Is there really need to jump out from the loop and exit in the case of
load_buddy failure ? Next group may very well succeed in loading buddy,
or am I missing something ?
> 2) IMHO runtime trim support is useful sometimes, for example when
> user really care about data security i.e. unlinked file should be
> trimmed ASAP. I think we have to provide 'secdel' mount option
> similar to secdeletion flag for inode, but this is another story
> not directly connected with the patch.
I like the idea, but IMO this should work for any underlying storage,
not just for SSDs.
Thanks!
-Lukas
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