criu/Documentation
Dan Feigin 97a87b82df criu: add --image-io-mode option to gate O_DIRECT reads of the pages image
Since #3022 restore reads the pages image with O_DIRECT unconditionally. That
helps a cold or cross-host restore, but on a same-host restore it bypasses the
still-warm cache and reads from disk, which made maps04 much slower (#3053).

Add an --image-io-mode option to select the pages-image I/O method: writeback
(default) keeps the buffered behaviour, direct uses O_DIRECT. It applies to both
dump and restore and can be set on the command line or over RPC.

Gate the restore side at the probe's call sites: open_page_read_at() and the
restore vma-io builder in mem.c switch the pages fd to O_DIRECT only when direct
mode was requested, so writeback keeps reading through the host page cache. The
probe itself no longer inspects the mode; as it now runs only on an explicit
request, its buffered-fallback log becomes a warning. The dump side follows in
the next commit.

Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Dan Feigin <dfeigin@nvidia.com>
2026-07-08 09:52:16 +01:00
..
under-the-hood docs: Clarify memory consistency and performance in pre-dump documentation 2026-06-25 13:16:05 -07:00
.gitattributes docs: Initial commit 2012-01-29 00:09:32 +04:00
.gitignore .gitignore: update to recent changes 2017-03-14 21:03:22 +03:00
asciidoc.conf docs: Initial commit 2012-01-29 00:09:32 +04:00
compel.txt infect: add SIGTSTP support 2023-04-15 21:17:21 -07:00
crit.txt crit: added crit manpage 2016-12-12 11:34:22 +03:00
criu-amdgpu-plugin.txt plugins/amdgpu: Update README.md and criu-amdgpu-plugin.txt 2025-11-14 18:27:31 +00:00
criu-ns.txt criu-ns: add support for 'check' action 2021-09-03 10:31:00 -07:00
criu.txt criu: add --image-io-mode option to gate O_DIRECT reads of the pages image 2026-07-08 09:52:16 +01:00
custom.xsl Documentation: enable monospaced font in PS/PDF 2016-09-27 17:06:02 +03:00
HOWTO.cross-compile Documentation: Add a hint about docker build 2020-02-04 12:39:04 -08:00
logo.svg readme: use a local copy of the CRIU logo 2025-12-17 08:43:50 -08:00
Makefile make: remove checks for python 2 binary 2023-10-22 13:29:25 -07:00