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| author | Hugh Dickins <hugh@veritas.com> | 2009-01-06 14:39:51 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-06 15:59:05 -0800 |
| commit | 6a6ba83175c029c7820765bae44692266b29e67a (patch) | |
| tree | 30bfb4938c73b715eb90dd15c09777fe0bbf93e6 /include | |
| parent | ebebbbe904634b0ca1c674457b399f68db5e05b1 (diff) | |
| download | linux-6a6ba83175c029c7820765bae44692266b29e67a.tar.bz2 | |
swapfile: swapon use discard (trim)
When adding swap, all the old data on swap can be forgotten: sys_swapon()
discard all but the header page of the swap partition (or every extent but
the header of the swap file), to give a solidstate swap device the
opportunity to optimize its wear-levelling.
If that succeeds, note SWP_DISCARDABLE for later use, and report it with a
"D" at the right end of the kernel's "Adding ... swap" message. Perhaps
something should be shown in /proc/swaps (swapon -s), but we have to be
more cautious before making any addition to that format.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Joern Engel <joern@logfs.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Donjun Shin <djshin90@gmail.com>
Cc: Tejun Heo <teheo@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/swap.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index 9cabb8b21aba..0b9210ea96c7 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -120,6 +120,7 @@ struct swap_extent { enum { SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ + SWP_DISCARDABLE = (1 << 2), /* blkdev supports discard */ /* add others here before... */ SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ }; |