* [PATCH] fs: annotate refault stalls from bdev_read_page
@ 2019-10-09 21:18 Minchan Kim
2019-10-09 22:25 ` Shakeel Butt
0 siblings, 1 reply; 3+ messages in thread
From: Minchan Kim @ 2019-10-09 21:18 UTC (permalink / raw)
To: Andrew Morton; +Cc: LKML, linux-mm, Minchan Kim, Johannes Weiner
From: Minchan Kim <minchan@google.com>
If block device supports rw_page operation, it doesn't submit bio
so annotation in submit_bio for refault stall doesn't work.
It happens with zram in android, especially swap read path which
could consume CPU cycle for decompress.
Annotate bdev_read_page() to account the synchronous IO overhead
to prevent underreport memory pressure.
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Minchan Kim <minchan@google.com>
---
fs/block_dev.c | 13 +++++++++++++
mm/memory.c | 1 +
2 files changed, 14 insertions(+)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9c073dbdc1b0..82ca28eb9a57 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -26,6 +26,7 @@
#include <linux/writeback.h>
#include <linux/mpage.h>
#include <linux/mount.h>
+#include <linux/psi.h>
#include <linux/pseudo_fs.h>
#include <linux/uio.h>
#include <linux/namei.h>
@@ -701,6 +702,8 @@ int bdev_read_page(struct block_device *bdev, sector_t sector,
{
const struct block_device_operations *ops = bdev->bd_disk->fops;
int result = -EOPNOTSUPP;
+ unsigned long pflags;
+ bool workingset_read;
if (!ops->rw_page || bdev_get_integrity(bdev))
return result;
@@ -708,9 +711,19 @@ int bdev_read_page(struct block_device *bdev, sector_t sector,
result = blk_queue_enter(bdev->bd_queue, 0);
if (result)
return result;
+
+ workingset_read = PageWorkingset(page);
+ if (workingset_read)
+ psi_memstall_enter(&pflags);
+
result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
REQ_OP_READ);
+
+ if (workingset_read)
+ psi_memstall_leave(&pflags);
+
blk_queue_exit(bdev->bd_queue);
+
return result;
}
EXPORT_SYMBOL_GPL(bdev_read_page);
diff --git a/mm/memory.c b/mm/memory.c
index 06935826d71e..6357d5a0a2a5 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2801,6 +2801,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
if (page) {
__SetPageLocked(page);
__SetPageSwapBacked(page);
+ SetPageWorkingset(page);
set_page_private(page, entry.val);
lru_cache_add_anon(page);
swap_readpage(page, true);
--
2.23.0.581.g78d2f28ef7-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] fs: annotate refault stalls from bdev_read_page
2019-10-09 21:18 [PATCH] fs: annotate refault stalls from bdev_read_page Minchan Kim
@ 2019-10-09 22:25 ` Shakeel Butt
2019-10-09 22:43 ` Minchan Kim
0 siblings, 1 reply; 3+ messages in thread
From: Shakeel Butt @ 2019-10-09 22:25 UTC (permalink / raw)
To: Minchan Kim; +Cc: Andrew Morton, LKML, linux-mm, Minchan Kim, Johannes Weiner
On Wed, Oct 9, 2019 at 2:19 PM Minchan Kim <minchan@kernel.org> wrote:
>
> From: Minchan Kim <minchan@google.com>
>
> If block device supports rw_page operation, it doesn't submit bio
> so annotation in submit_bio for refault stall doesn't work.
> It happens with zram in android, especially swap read path which
> could consume CPU cycle for decompress.
What about zswap? Do we need the same in zswap_frontswap_load()?
>
> Annotate bdev_read_page() to account the synchronous IO overhead
> to prevent underreport memory pressure.
>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Minchan Kim <minchan@google.com>
> ---
> fs/block_dev.c | 13 +++++++++++++
> mm/memory.c | 1 +
> 2 files changed, 14 insertions(+)
>
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index 9c073dbdc1b0..82ca28eb9a57 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -26,6 +26,7 @@
> #include <linux/writeback.h>
> #include <linux/mpage.h>
> #include <linux/mount.h>
> +#include <linux/psi.h>
> #include <linux/pseudo_fs.h>
> #include <linux/uio.h>
> #include <linux/namei.h>
> @@ -701,6 +702,8 @@ int bdev_read_page(struct block_device *bdev, sector_t sector,
> {
> const struct block_device_operations *ops = bdev->bd_disk->fops;
> int result = -EOPNOTSUPP;
> + unsigned long pflags;
> + bool workingset_read;
>
> if (!ops->rw_page || bdev_get_integrity(bdev))
> return result;
> @@ -708,9 +711,19 @@ int bdev_read_page(struct block_device *bdev, sector_t sector,
> result = blk_queue_enter(bdev->bd_queue, 0);
> if (result)
> return result;
> +
> + workingset_read = PageWorkingset(page);
> + if (workingset_read)
> + psi_memstall_enter(&pflags);
> +
> result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
> REQ_OP_READ);
> +
> + if (workingset_read)
> + psi_memstall_leave(&pflags);
> +
> blk_queue_exit(bdev->bd_queue);
> +
> return result;
> }
> EXPORT_SYMBOL_GPL(bdev_read_page);
> diff --git a/mm/memory.c b/mm/memory.c
> index 06935826d71e..6357d5a0a2a5 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -2801,6 +2801,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
> if (page) {
> __SetPageLocked(page);
> __SetPageSwapBacked(page);
> + SetPageWorkingset(page);
> set_page_private(page, entry.val);
> lru_cache_add_anon(page);
> swap_readpage(page, true);
> --
> 2.23.0.581.g78d2f28ef7-goog
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] fs: annotate refault stalls from bdev_read_page
2019-10-09 22:25 ` Shakeel Butt
@ 2019-10-09 22:43 ` Minchan Kim
0 siblings, 0 replies; 3+ messages in thread
From: Minchan Kim @ 2019-10-09 22:43 UTC (permalink / raw)
To: Shakeel Butt; +Cc: Andrew Morton, LKML, linux-mm, Johannes Weiner
On Wed, Oct 09, 2019 at 03:25:10PM -0700, Shakeel Butt wrote:
> On Wed, Oct 9, 2019 at 2:19 PM Minchan Kim <minchan@kernel.org> wrote:
> >
> > From: Minchan Kim <minchan@google.com>
> >
> > If block device supports rw_page operation, it doesn't submit bio
> > so annotation in submit_bio for refault stall doesn't work.
> > It happens with zram in android, especially swap read path which
> > could consume CPU cycle for decompress.
>
> What about zswap? Do we need the same in zswap_frontswap_load()?
Yub, it needs it. Maybe, a annotation in swap_readpage will cover both
all at once in real pratice unless we need to take care of nvdimms
which supports rw_page operation.
Thanks.
>
> >
> > Annotate bdev_read_page() to account the synchronous IO overhead
> > to prevent underreport memory pressure.
> >
> > Cc: Johannes Weiner <hannes@cmpxchg.org>
> > Signed-off-by: Minchan Kim <minchan@google.com>
> > ---
> > fs/block_dev.c | 13 +++++++++++++
> > mm/memory.c | 1 +
> > 2 files changed, 14 insertions(+)
> >
> > diff --git a/fs/block_dev.c b/fs/block_dev.c
> > index 9c073dbdc1b0..82ca28eb9a57 100644
> > --- a/fs/block_dev.c
> > +++ b/fs/block_dev.c
> > @@ -26,6 +26,7 @@
> > #include <linux/writeback.h>
> > #include <linux/mpage.h>
> > #include <linux/mount.h>
> > +#include <linux/psi.h>
> > #include <linux/pseudo_fs.h>
> > #include <linux/uio.h>
> > #include <linux/namei.h>
> > @@ -701,6 +702,8 @@ int bdev_read_page(struct block_device *bdev, sector_t sector,
> > {
> > const struct block_device_operations *ops = bdev->bd_disk->fops;
> > int result = -EOPNOTSUPP;
> > + unsigned long pflags;
> > + bool workingset_read;
> >
> > if (!ops->rw_page || bdev_get_integrity(bdev))
> > return result;
> > @@ -708,9 +711,19 @@ int bdev_read_page(struct block_device *bdev, sector_t sector,
> > result = blk_queue_enter(bdev->bd_queue, 0);
> > if (result)
> > return result;
> > +
> > + workingset_read = PageWorkingset(page);
> > + if (workingset_read)
> > + psi_memstall_enter(&pflags);
> > +
> > result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
> > REQ_OP_READ);
> > +
> > + if (workingset_read)
> > + psi_memstall_leave(&pflags);
> > +
> > blk_queue_exit(bdev->bd_queue);
> > +
> > return result;
> > }
> > EXPORT_SYMBOL_GPL(bdev_read_page);
> > diff --git a/mm/memory.c b/mm/memory.c
> > index 06935826d71e..6357d5a0a2a5 100644
> > --- a/mm/memory.c
> > +++ b/mm/memory.c
> > @@ -2801,6 +2801,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
> > if (page) {
> > __SetPageLocked(page);
> > __SetPageSwapBacked(page);
> > + SetPageWorkingset(page);
> > set_page_private(page, entry.val);
> > lru_cache_add_anon(page);
> > swap_readpage(page, true);
> > --
> > 2.23.0.581.g78d2f28ef7-goog
> >
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-10-09 21:18 [PATCH] fs: annotate refault stalls from bdev_read_page Minchan Kim
2019-10-09 22:25 ` Shakeel Butt
2019-10-09 22:43 ` Minchan Kim
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