Messages in this thread | | | From | Linus Torvalds <> | Date | Fri, 20 Sep 2019 16:05:17 -0700 | Subject | Re: [PATCH v2] mm: implement write-behind policy for sequential file writes |
| |
On Fri, Sep 20, 2019 at 12:35 AM Konstantin Khlebnikov <khlebnikov@yandex-team.ru> wrote: > > This patch implements write-behind policy which tracks sequential writes > and starts background writeback when file have enough dirty pages.
Apart from a spelling error ("contigious"), my only reaction is that I've wanted this for the multi-file writes, not just for single big files.
Yes, single big files may be a simpler and perhaps the "10% effort for 90% of the gain", and thus the right thing to do, but I do wonder if you've looked at simply extending it to cover multiple files when people copy a whole directory (or unpack a tar-file, or similar).
Now, I hear you say "those are so small these days that it doesn't matter". And maybe you're right. But partiocularly for slow media, triggering good streaming write behavior has been a problem in the past.
So I'm wondering whether the "writebehind" state should perhaps be considered be a process state, rather than "struct file" state, and also start triggering for writing smaller files.
Maybe this was already discussed and people decided that the big-file case was so much easier that it wasn't worth worrying about writebehind for multiple files.
Linus
| |