diff options
| author | NeilBrown <neilb@suse.de> | 2022-05-09 18:20:49 -0700 |
|---|---|---|
| committer | akpm <akpm@linux-foundation.org> | 2022-05-09 18:20:49 -0700 |
| commit | 2282679fb20bf036a714ed49fadd0230c278a203 (patch) | |
| tree | 9d800e63a82d3405fd1897ab4b8e3873d7ebb561 /include/linux/writeback.h | |
| parent | 5169b844b7dd5934cd4f22ab66de0cc669abf0b0 (diff) | |
| download | linux-2282679fb20bf036a714ed49fadd0230c278a203.tar.gz | |
mm: submit multipage write for SWP_FS_OPS swap-space
swap_writepage() is given one page at a time, but may be called repeatedly
in succession.
For block-device swapspace, the blk_plug functionality allows the multiple
pages to be combined together at lower layers. That cannot be used for
SWP_FS_OPS as blk_plug may not exist - it is only active when
CONFIG_BLOCK=y. Consequently all swap reads over NFS are single page
reads.
With this patch we pass a pointer-to-pointer via the wbc. swap_writepage
can store state between calls - much like the pointer passed explicitly to
swap_readpage. After calling swap_writepage() some number of times, the
state will be passed to swap_write_unplug() which can submit the combined
request.
Link: https://lkml.kernel.org/r/164859778128.29473.5191868522654408537.stgit@noble.brown
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: David Howells <dhowells@redhat.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/writeback.h')
| -rw-r--r-- | include/linux/writeback.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/writeback.h b/include/linux/writeback.h index fec248ab1fec58..32b35f21cb97ec 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -80,6 +80,13 @@ struct writeback_control { unsigned punt_to_cgroup:1; /* cgrp punting, see __REQ_CGROUP_PUNT */ + /* To enable batching of swap writes to non-block-device backends, + * "plug" can be set point to a 'struct swap_iocb *'. When all swap + * writes have been submitted, if with swap_iocb is not NULL, + * swap_write_unplug() should be called. + */ + struct swap_iocb **swap_plug; + #ifdef CONFIG_CGROUP_WRITEBACK struct bdi_writeback *wb; /* wb this writeback is issued under */ struct inode *inode; /* inode being written out */ |