+ mm-annotate-refault-stalls-from-swap_readpage.patch added to -mm tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The patch titled
     Subject: mm/page_io.c: annotate refault stalls from swap_readpage
has been added to the -mm tree.  Its filename is
     mm-annotate-refault-stalls-from-swap_readpage.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-annotate-refault-stalls-from-swap_readpage.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-annotate-refault-stalls-from-swap_readpage.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Minchan Kim <minchan@xxxxxxxxxx>
Subject: mm/page_io.c: annotate refault stalls from swap_readpage

If a block device supports rw_page operation, it doesn't submit bios so
the 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.  It is also a problem for zswap which uses
frontswap.

Annotate swap_readpage() to account the synchronous IO overhead to prevent
underreport memory pressure.

Link: http://lkml.kernel.org/r/20191010152134.38545-1-minchan@xxxxxxxxxx
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/page_io.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/mm/page_io.c~mm-annotate-refault-stalls-from-swap_readpage
+++ a/mm/page_io.c
@@ -22,6 +22,7 @@
 #include <linux/writeback.h>
 #include <linux/frontswap.h>
 #include <linux/blkdev.h>
+#include <linux/psi.h>
 #include <linux/uio.h>
 #include <linux/sched/task.h>
 #include <asm/pgtable.h>
@@ -354,10 +355,14 @@ int swap_readpage(struct page *page, boo
 	struct swap_info_struct *sis = page_swap_info(page);
 	blk_qc_t qc;
 	struct gendisk *disk;
+	unsigned long pflags;
 
 	VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page);
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 	VM_BUG_ON_PAGE(PageUptodate(page), page);
+
+	psi_memstall_enter(&pflags);
+
 	if (frontswap_load(page) == 0) {
 		SetPageUptodate(page);
 		unlock_page(page);
@@ -371,7 +376,7 @@ int swap_readpage(struct page *page, boo
 		ret = mapping->a_ops->readpage(swap_file, page);
 		if (!ret)
 			count_vm_event(PSWPIN);
-		return ret;
+		goto out;
 	}
 
 	ret = bdev_read_page(sis->bdev, swap_page_sector(page), page);
@@ -382,7 +387,7 @@ int swap_readpage(struct page *page, boo
 		}
 
 		count_vm_event(PSWPIN);
-		return 0;
+		goto out;
 	}
 
 	ret = 0;
@@ -418,6 +423,7 @@ int swap_readpage(struct page *page, boo
 	bio_put(bio);
 
 out:
+	psi_memstall_leave(&pflags);
 	return ret;
 }
 
_

Patches currently in -mm which might be from minchan@xxxxxxxxxx are

mm-annotate-refault-stalls-from-swap_readpage.patch




[Index of Archives]     [Kernel Archive]     [IETF Annouce]     [DCCP]     [Netdev]     [Networking]     [Security]     [Bugtraq]     [Yosemite]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux SCSI]

  Powered by Linux