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authorYang Yang <yang.yang29@zte.com.cn>2022-06-02 01:55:25 +0300
committerakpm <akpm@linux-foundation.org>2022-06-02 01:55:25 +0300
commit662ce1dc9caf493c309200edbe38d186f1ea20d0 (patch)
treee49eeda0a61590b5843d47d1be17dbb18cf3aaa1 /mm
parent54eb8462f21fb170a05ad64620f0d8d0cf2b7fb5 (diff)
downloadlinux-662ce1dc9caf493c309200edbe38d186f1ea20d0.tar.xz
delayacct: track delays from write-protect copy
Delay accounting does not track the delay of write-protect copy. When tasks trigger many write-protect copys(include COW and unsharing of anonymous pages[1]), it may spend a amount of time waiting for them. To get the delay of tasks in write-protect copy, could help users to evaluate the impact of using KSM or fork() or GUP. Also update tools/accounting/getdelays.c: / # ./getdelays -dl -p 231 print delayacct stats ON listen forever PID 231 CPU count real total virtual total delay total delay average 6247 1859000000 2154070021 1674255063 0.268ms IO count delay total delay average 0 0 0ms SWAP count delay total delay average 0 0 0ms RECLAIM count delay total delay average 0 0 0ms THRASHING count delay total delay average 0 0 0ms COMPACT count delay total delay average 3 72758 0ms WPCOPY count delay total delay average 3635 271567604 0ms [1] commit 31cc5bc4af70("mm: support GUP-triggered unsharing of anonymous pages") Link: https://lkml.kernel.org/r/20220409014342.2505532-1-yang.yang29@zte.com.cn Signed-off-by: Yang Yang <yang.yang29@zte.com.cn> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Jiang Xuexin <jiang.xuexin@zte.com.cn> Reviewed-by: Ran Xiaokai <ran.xiaokai@zte.com.cn> Reviewed-by: wangyong <wang.yong12@zte.com.cn> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/hugetlb.c8
-rw-r--r--mm/memory.c8
2 files changed, 16 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 7c468ac1d069..a57e1be41401 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -32,6 +32,7 @@
#include <linux/cma.h>
#include <linux/migrate.h>
#include <linux/nospec.h>
+#include <linux/delayacct.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
@@ -5230,6 +5231,8 @@ static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
pte = huge_ptep_get(ptep);
old_page = pte_page(pte);
+ delayacct_wpcopy_start();
+
retry_avoidcopy:
/*
* If no-one else is actually using this page, we're the exclusive
@@ -5240,6 +5243,8 @@ retry_avoidcopy:
page_move_anon_rmap(old_page, vma);
if (likely(!unshare))
set_huge_ptep_writable(vma, haddr, ptep);
+
+ delayacct_wpcopy_end();
return 0;
}
VM_BUG_ON_PAGE(PageAnon(old_page) && PageAnonExclusive(old_page),
@@ -5309,6 +5314,7 @@ retry_avoidcopy:
* race occurs while re-acquiring page table
* lock, and our job is done.
*/
+ delayacct_wpcopy_end();
return 0;
}
@@ -5367,6 +5373,8 @@ out_release_old:
put_page(old_page);
spin_lock(ptl); /* Caller expects lock to be held */
+
+ delayacct_wpcopy_end();
return ret;
}
diff --git a/mm/memory.c b/mm/memory.c
index 21dadf03f089..7a089145cad4 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3090,6 +3090,8 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
int page_copied = 0;
struct mmu_notifier_range range;
+ delayacct_wpcopy_start();
+
if (unlikely(anon_vma_prepare(vma)))
goto oom;
@@ -3114,6 +3116,8 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
put_page(new_page);
if (old_page)
put_page(old_page);
+
+ delayacct_wpcopy_end();
return 0;
}
}
@@ -3220,12 +3224,16 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
free_swap_cache(old_page);
put_page(old_page);
}
+
+ delayacct_wpcopy_end();
return (page_copied && !unshare) ? VM_FAULT_WRITE : 0;
oom_free_new:
put_page(new_page);
oom:
if (old_page)
put_page(old_page);
+
+ delayacct_wpcopy_end();
return VM_FAULT_OOM;
}