linux-kernel - Re: [PATCH 2/2] msync: start async writeout when MS

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Thu, 14 Jun 2012 14:24:51 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	linux-kernel@...r.kernel.org, Hugh Dickins <hughd@...gle.com>
Subject: Re: [PATCH 2/2] msync: start async writeout when MS_ASYNC

Il 13/06/2012 23:29, Andrew Morton ha scritto:
> Also, it hardwires into the kernel behaviour which userspace itself
> could have initiated, with sync_file_range().  ie: reduced flexibility.

Actually sync_file_range calls filemap_fdatawrite_range with
WB_SYNC_ALL, hence it does the writeout synchronously and can block for
an extended period of time.  Hence sync_file_range is more similar to
MS_SYNC except without the metadata write.

Instead, this patch uses WB_SYNC_NONE, while still using tag-and-write
to avoid livelock.

I'll wait a day or two to let others voice their opinions, and then send
a fixed v2 with updated commit messages from this discussion.

Paolo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/