* + userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.patch added to -mm tree
@ 2021-05-09 4:09 akpm
0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2021-05-09 4:09 UTC (permalink / raw)
To: aarcange, almasrymina, axelrasmussen, bgeffon, dgilbert, hughd,
jglisse, joe, kirill, lokeshgidra, mike.kravetz, mm-commits,
oupton, peterx, rppt, sfr, shli, shuah, viro, wangqing
The patch titled
Subject: userfaultfd/selftests: remove the time() check on delayed uffd
has been added to the -mm tree. Its filename is
userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.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: Peter Xu <peterx@redhat.com>
Subject: userfaultfd/selftests: remove the time() check on delayed uffd
There seems to have no guarantee that time() will return the same for the
two calls even if there's no delay, e.g. when a fault is accidentally
crossing the changing of a second. Meanwhile, this message is also not
helping that much since delay could happen with a lot of reasons, e.g.,
schedule latency of resolving thread. It may not mean an issue with uffd.
Neither do I saw this error triggered either in the past runs. Even if it
triggers, it'll be drown in all the rest of test logs. Remove it.
Link: https://lkml.kernel.org/r/20210412232753.1012412-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Wang Qing <wangqing@vivo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
tools/testing/selftests/vm/userfaultfd.c | 8 --------
1 file changed, 8 deletions(-)
--- a/tools/testing/selftests/vm/userfaultfd.c~userfaultfd-selftests-remove-the-time-check-on-delayed-uffd
+++ a/tools/testing/selftests/vm/userfaultfd.c
@@ -395,7 +395,6 @@ static void *locking_thread(void *arg)
unsigned long long count;
char randstate[64];
unsigned int seed;
- time_t start;
if (bounces & BOUNCE_RANDOM) {
seed = (unsigned int) time(NULL) - bounces;
@@ -432,7 +431,6 @@ static void *locking_thread(void *arg)
page_nr += 1;
page_nr %= nr_pages;
- start = time(NULL);
if (bounces & BOUNCE_VERIFY) {
count = *area_count(area_dst, page_nr);
if (!count) {
@@ -495,12 +493,6 @@ static void *locking_thread(void *arg)
count++;
*area_count(area_dst, page_nr) = count_verify[page_nr] = count;
pthread_mutex_unlock(area_mutex(area_dst, page_nr));
-
- if (time(NULL) - start > 1)
- fprintf(stderr,
- "userfault too slow %ld "
- "possible false positive with overcommit\n",
- time(NULL) - start);
}
return NULL;
_
Patches currently in -mm which might be from peterx@redhat.com are
mm-hugetlb-fix-f_seal_future_write.patch
mm-hugetlb-fix-cow-where-page-writtable-in-child.patch
mm-gup_benchmark-support-threading.patch
userfaultfd-selftests-use-user-mode-only.patch
userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.patch
userfaultfd-selftests-dropping-verify-check-in-locking_thread.patch
userfaultfd-selftests-only-dump-counts-if-mode-enabled.patch
userfaultfd-selftests-unify-error-handling.patch
mm-thp-simplify-copying-of-huge-zero-page-pmd-when-fork.patch
mm-userfaultfd-fix-uffd-wp-special-cases-for-fork.patch
mm-userfaultfd-fix-a-few-thp-pmd-missing-uffd-wp-bit.patch
mm-userfaultfd-fail-uffd-wp-registeration-if-not-supported.patch
mm-pagemap-export-uffd-wp-protection-information.patch
userfaultfd-selftests-add-pagemap-uffd-wp-test.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
* + userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.patch added to -mm tree
@ 2021-03-10 23:53 akpm
0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2021-03-10 23:53 UTC (permalink / raw)
To: aarcange, axelrasmussen, mm-commits, nadav.amit, peterx
The patch titled
Subject: userfaultfd/selftests: remove the time() check on delayed uffd
has been added to the -mm tree. Its filename is
userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.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: Peter Xu <peterx@redhat.com>
Subject: userfaultfd/selftests: remove the time() check on delayed uffd
There seems to have no guarantee that time() will return the same for the
two calls even if there's no delay, e.g. when a fault is accidentally
crossing the changing of a second. Meanwhile, this message is also not
helping that much since delay could happen with a lot of reasons, e.g.,
schedule latency of resolving thread. It may not mean an issue with uffd.
Neither do I see this error triggered either in the past runs. Even if it
triggers, it'll be drown in all the rest of test logs. Remove it.
Link: https://lkml.kernel.org/r/20210310004511.51996-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
tools/testing/selftests/vm/userfaultfd.c | 8 --------
1 file changed, 8 deletions(-)
--- a/tools/testing/selftests/vm/userfaultfd.c~userfaultfd-selftests-remove-the-time-check-on-delayed-uffd
+++ a/tools/testing/selftests/vm/userfaultfd.c
@@ -568,7 +568,6 @@ static void *locking_thread(void *arg)
unsigned long long count;
char randstate[64];
unsigned int seed;
- time_t start;
if (bounces & BOUNCE_RANDOM) {
seed = (unsigned int) time(NULL) - bounces;
@@ -605,7 +604,6 @@ static void *locking_thread(void *arg)
page_nr += 1;
page_nr %= nr_pages;
- start = time(NULL);
if (bounces & BOUNCE_VERIFY) {
count = *area_count(area_dst, page_nr);
if (!count) {
@@ -668,12 +666,6 @@ static void *locking_thread(void *arg)
count++;
*area_count(area_dst, page_nr) = count_verify[page_nr] = count;
pthread_mutex_unlock(area_mutex(area_dst, page_nr));
-
- if (time(NULL) - start > 1)
- fprintf(stderr,
- "userfault too slow %ld "
- "possible false positive with overcommit\n",
- time(NULL) - start);
}
return NULL;
_
Patches currently in -mm which might be from peterx@redhat.com are
hugetlb-dedup-the-code-to-add-a-new-file_region.patch
hugetlg-break-earlier-in-add_reservation_in_range-when-we-can.patch
mm-introduce-page_needs_cow_for_dma-for-deciding-whether-cow.patch
mm-use-is_cow_mapping-across-tree-where-proper.patch
hugetlb-do-early-cow-when-page-pinned-on-src-mm.patch
hugetlb-pass-vma-into-huge_pte_alloc-and-huge_pmd_share.patch
hugetlb-pass-vma-into-huge_pte_alloc-and-huge_pmd_share-fix.patch
hugetlb-userfaultfd-forbid-huge-pmd-sharing-when-uffd-enabled.patch
hugetlb-userfaultfd-forbid-huge-pmd-sharing-when-uffd-enabled-fix.patch
mm-hugetlb-move-flush_hugetlb_tlb_range-into-hugetlbh.patch
hugetlb-userfaultfd-unshare-all-pmds-for-hugetlbfs-when-register-wp.patch
userfaultfd-selftests-use-user-mode-only.patch
userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.patch
userfaultfd-selftests-dropping-verify-check-in-locking_thread.patch
userfaultfd-selftests-only-dump-counts-if-mode-enabled.patch
userfaultfd-selftests-unify-error-handling.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-05-09 4:09 + userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.patch added to -mm tree akpm
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2021-03-10 23:53 akpm
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