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author | Minchan Kim <minchan@kernel.org> | 2013-09-25 18:57:43 -0500 |
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committer | Andreas Blaesius <skate4life@gmx.de> | 2016-06-05 21:21:56 +0200 |
commit | fe6357ae0e88cbe9453e30820151921e68f43c1c (patch) | |
tree | 61420acb686501d9c4eb59132b85929e5bc94889 /include/linux/page-flags.h | |
parent | 9046d8fd97e123866acab7852a25ae796ca771b5 (diff) | |
download | kernel_samsung_espresso10-fe6357ae0e88cbe9453e30820151921e68f43c1c.zip kernel_samsung_espresso10-fe6357ae0e88cbe9453e30820151921e68f43c1c.tar.gz kernel_samsung_espresso10-fe6357ae0e88cbe9453e30820151921e68f43c1c.tar.bz2 |
mm: remove compressed copy from zram in-memory
Swap subsystem does lazy swap slot free with expecting the page would be
swapped out again so we can avoid unnecessary write.
But the problem in in-memory swap(ex, zram) is that it consumes memory
space until vm_swap_full(ie, used half of all of swap device) condition
meet. It could be bad if we use multiple swap device, small in-memory
swap and big storage swap or in-memory swap alone.
This patch makes swap subsystem free swap slot as soon as swap-read is
completed and make the swapcache page dirty so the page should be
written out the swap device to reclaim it. It means we never lose it.
I tested this patch with kernel compile workload.
1. before
compile time : 9882.42
zram max wasted space by fragmentation: 13471881 byte
memory space consumed by zram: 174227456 byte
the number of slot free notify: 206684
2. after
compile time : 9653.90
zram max wasted space by fragmentation: 11805932 byte
memory space consumed by zram: 154001408 byte
the number of slot free notify: 426972
[akpm@linux-foundation.org: tweak comment text]
[artem.savkov@gmail.com: fix BUG due to non-swapcache pages in end_swap_bio_read()]
[akpm@linux-foundation.org: invert unlikely() test, augment comment, 80-col cleanup]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Artem Savkov <artem.savkov@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Konrad Rzeszutek Wilk <konrad@darnok.org>
Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: I8f11fb7f0391954435002e7f290352f311c907d4
Signed-off-by: Paul Reioux <reioux@gmail.com>
Conflicts:
mm/page_io.c
Diffstat (limited to 'include/linux/page-flags.h')
0 files changed, 0 insertions, 0 deletions