On Tue, Feb 22, 2011 at 10:42:41AM -0800, Chad Talbott wrote:

On Tue, Feb 22, 2011 at 9:12 AM, Andrea Righi [off-list ref] wrote:

quoted

Add the tracking of buffered (writeback) and anonymous pages.

...

quoted

---
 block/blk-throttle.c   |   87 +++++++++++++++++++++++++++++++++++++++++++++++-
 include/linux/blkdev.h |   26 ++++++++++++++-
 2 files changed, 111 insertions(+), 2 deletions(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 9ad3d1e..a50ee04 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c

...

quoted

+int blk_throtl_set_anonpage_owner(struct page *page, struct mm_struct *mm)
+int blk_throtl_set_filepage_owner(struct page *page, struct mm_struct *mm)
+int blk_throtl_copy_page_owner(struct page *npage, struct page *opage)

It would be nice if these were named blk_cgroup_*.  This is arguably
more correct as the id comes from the blkio subsystem, and isn't
specific to blk-throttle.  This will be more important very shortly,
as CFQ will be using this same cgroup id for async IO tracking soon.

Sounds reasonable. Will do in the next version.

is_kernel_io() is a good idea, it avoids a bug that we've run into
with CFQ async IO tracking.  Why isn't PF_KTHREAD sufficient to cover
all kernel threads, including kswapd and those marked PF_MEMALLOC?

With PF_MEMALLOC we're sure we don't add the page tracking overhead also
to non-kernel threads when memory gets low.

PF_KSWAPD is not probably needed, AFAICS it is only used by kswapd, that
is created by kthread_create() and so it has the PF_KTHREAD flag set.

Let's see if someone can give more deatils about that. In the while I'll
investigate and try to do some tests only with PF_KTHREAD.

Thanks,
-Andrea

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