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slw_zxy.spb.ru (Slawa Olhovchenkov)
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Aug 16 2016, 9:48 PM (139 w, 5 d)

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Mar 11 2019

slw_zxy.spb.ru added a comment to D19094: Restore ARC MFU/MRU pressure.
In D19094#418092, @avg wrote:

No more replays?

Unfortunately, no.
I think that we can commit your proposed change. If George comes up with a different and better solution later on, there should be no problem switching to it.

Mar 11 2019, 10:28 AM · ZFS

Mar 7 2019

slw_zxy.spb.ru added a comment to D19094: Restore ARC MFU/MRU pressure.
In D19094#412736, @avg wrote:

Do you succesefull contact George?

I've just got a reply from George.
He agrees with your analysis, but needs some more time to think about how to address the issue.
Let's wait a bit more.
Thanks!

Mar 7 2019, 10:08 AM · ZFS

Feb 19 2019

slw_zxy.spb.ru added a comment to D19094: Restore ARC MFU/MRU pressure.
In D19094#410508, @avg wrote:

Let me try to contact George again.

Feb 19 2019, 9:46 PM · ZFS

Feb 13 2019

slw_zxy.spb.ru added a comment to D19094: Restore ARC MFU/MRU pressure.
In D19094#410239, @mav wrote:

Don't sure about calling remove_reference() from arc_hdr_alloc_pabd() (or from parallel tasks), but see at ARC MFU/MRU size calculation in arc_change_state() called from arc_access() and !GHOST_STATE(state) case in arc_get_data_impl() called from arc_hdr_alloc_pabd().
I mean interchange this lines can cause problems for this accountings.

I am not sure what accounting problem you are talking about,

Feb 13 2019, 7:08 PM · ZFS
slw_zxy.spb.ru added a comment to D19094: Restore ARC MFU/MRU pressure.
In D19094#410062, @mav wrote:

While I see the problem you are fixing, the fix looks ugly to me, that is why I would look for something nicer.

Feb 13 2019, 2:15 PM · ZFS

Feb 6 2019

slw_zxy.spb.ru created D19094: Restore ARC MFU/MRU pressure.
Feb 6 2019, 2:48 PM · ZFS

Aug 29 2018

slw_zxy.spb.ru added a comment to D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.
  1. ARC don't rised, memory pressure does not arise, page daemon not activated.

The ARC is not growing after 8, but the ARC hit rate is too low. Why is it not growing? Is it because the free_memory < (arc_c >> arc_no_grow_shift) condition is true, or is there some other reason?

Aug 29 2018, 7:57 PM · ZFS

Aug 28 2018

slw_zxy.spb.ru added a comment to D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.
In D7538#361135, @markj wrote:

To be clear, I'm just stating that r332365 changed zfs_arc_free_target to be equal vm_cnt.v_free_target. It looks to me that this is equivalent to the change you made to arc_available_memory(EXCLUDE_ZONE_CACHE), where v_free_target is referenced directly.

No.
arc_available_memory(EXCLUDE_ZONE_CACHE) check conditions for memory pressure, check how many free memory see by OS (and kmem cache not counted for this).

Yes, which is exactly what the computation freemem - zfs_arc_free_target is. If you expand these definitions, it is vm_cnt.v_free_count - vm_cnt.v_free_target, where v_free_count does not include UMA caches. When v_free_count < v_free_target, the system is under memory pressure, and the page daemon attempts to free pages until v_free_count >= v_free_target. In -CURRENT, you can think of needfree as being the same as v_free_target - v_free_target when this difference is positive. In stable branches this is not quite true.

Aug 28 2018, 11:12 PM · ZFS

Aug 23 2018

slw_zxy.spb.ru added a comment to D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.

To be clear, I'm just stating that r332365 changed zfs_arc_free_target to be equal vm_cnt.v_free_target. It looks to me that this is equivalent to the change you made to arc_available_memory(EXCLUDE_ZONE_CACHE), where v_free_target is referenced directly.

Aug 23 2018, 10:04 PM · ZFS
slw_zxy.spb.ru added a comment to D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.
In D7538#358922, @markj wrote:

Sorry that this review has stalled lately. I would like to compare this patch to what's in -CURRENT, which has evolved a fair bit since the patch was updated. Once that picture is more clear, we can focus on stable/11.

Aug 23 2018, 1:26 PM · ZFS

Jun 18 2018

slw_zxy.spb.ru added a comment to D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.

I have come to realise that there is another issue related to this, the default arc_max being wired ram that is not counted in max_wired means a default setup is allowed to wire more than the physical ram installed.
See my comment here for more explanation.

Jun 18 2018, 1:53 PM · ZFS

May 22 2018

slw_zxy.spb.ru updated the diff for D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.

Unified for -stable and current now

May 22 2018, 3:49 PM · ZFS

May 11 2018

slw_zxy.spb.ru updated the diff for D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.

Update to latest -STABLE changes

May 11 2018, 10:16 PM · ZFS

Sep 28 2017

slw_zxy.spb.ru added a comment to D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.

As some of you probably know I've been chasing this same general issue here: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=187594
I'm playing with this patch set now on 11.1-STABLE (r324056) and other than leaving a crazy amount of inactive pages outstanding (which never get reclaimed in many instances, thus pressuring ARC size to half or so of what it could otherwise be) it appears to behave well.
I think I've got a fix for that last issue, and this patch set is a more-elegant approach to the UMA bloat problem then I had come up with. I want to run my changes to this code for a few days before contributing my thoughts in the form of code, but the short version is that adding a pager wakeup somewhat above the low-memory threshold appears to resolve the "frozen" inactive page issue and, if that proves up, this patch set looks very good and somewhat-superior to the one I have been running for ofa while (and thus a better option.)

Sep 28 2017, 10:30 PM · ZFS

Mar 18 2017

slw_zxy.spb.ru updated the diff for D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.
  1. Restore lost code
  2. Conrtol (by sysctl) draining per-CPU UMA cache
  3. Skip first draining UMA cache for case of enough memory in caches.
  4. Don't wait drained memory accounted as free. Stop daining if expect as enough.
Mar 18 2017, 10:34 AM · ZFS

Mar 5 2017

slw_zxy.spb.ru updated the diff for D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.

Fix userland compilation

Mar 5 2017, 1:43 PM · ZFS

Mar 4 2017

slw_zxy.spb.ru updated the diff for D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.

Generalize zone travers algorithm and do some optimization on cache reclaim (arc_kmem_reap_now() costly and call only as last resort)

Mar 4 2017, 4:09 PM · ZFS

Mar 2 2017

slw_zxy.spb.ru updated the diff for D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.

Optimize zone processing

Mar 2 2017, 12:59 PM · ZFS
slw_zxy.spb.ru updated the diff for D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.

per-CPU cache must be drained before zone drain

Mar 2 2017, 11:53 AM · ZFS

Mar 1 2017

slw_zxy.spb.ru updated the diff for D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.

fix typo again

Mar 1 2017, 9:11 AM · ZFS
slw_zxy.spb.ru updated D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.
Mar 1 2017, 8:43 AM · ZFS
slw_zxy.spb.ru updated the diff for D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.

fix typo

Mar 1 2017, 8:42 AM · ZFS
slw_zxy.spb.ru updated the diff for D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.
  1. Check size of free items in zones (now eleminate false pressure to ARC by per-CPU zone cache)
  2. Do cleanup per-CPU zone cache after arc_kmem_reap_now() (immediatle available as free memory shrinked ARC cache)
Mar 1 2017, 8:40 AM · ZFS

Feb 14 2017

slw_zxy.spb.ru added a comment to D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.
In D7538#198159, @avg wrote:
  • there needs to be a very good explanation of why we would want to calculate needfree in the proposed fashion

main goal: don't allow drop freemem below v_free_min

I think that the existing check handles that already.

Feb 14 2017, 2:55 PM · ZFS
slw_zxy.spb.ru added a comment to D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.
  • there needs to be a very good explanation of why we would want to calculate needfree in the proposed fashion
Feb 14 2017, 2:37 PM · ZFS
slw_zxy.spb.ru added a comment to D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.
In D7538#198085, @avg wrote:
  • I don't think that the needfree calculations in the patch are correct
    • in illumos needfree means something entirely different from what's calculated in the patch
    • there needs to be a very good explanation of why we would want to calculate needfree in the proposed fashion
Feb 14 2017, 2:01 PM · ZFS

Feb 13 2017

slw_zxy.spb.ru added inline comments to D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.
Feb 13 2017, 8:47 PM · ZFS
slw_zxy.spb.ru updated the diff for D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.
Feb 13 2017, 7:27 PM · ZFS

Oct 17 2016

slw_zxy.spb.ru added a comment to D8211: Fix a double-free when an inp transitions to INP_TIMEWAIT state after having been dropped..

I was testing this patch in 3 days.
No TCP related problems.

Oct 17 2016, 10:38 AM

Oct 10 2016

slw_zxy.spb.ru added a comment to D8211: Fix a double-free when an inp transitions to INP_TIMEWAIT state after having been dropped..

I think imp also have reproduced this issue (https://lists.freebsd.org/pipermail/freebsd-stable/2016-September/085518.html)
Also report Urmas Lett <urmas.lett@eenet.ee> (email to jch)

Oct 10 2016, 11:22 AM

Aug 17 2016

slw_zxy.spb.ru updated the diff for D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD.

Illumos update needfree by kmem susbsystem. On FreeBSD emulate this in next way:

Aug 17 2016, 1:44 PM · ZFS

Aug 16 2016

slw_zxy.spb.ru retitled D7538: Correct adaptation ZFS ARC memory pressure to FreeBSD from to Correct adaptation of needfree (from illumos) to FreeBSD (ZFS ARC memory pressure).
Aug 16 2016, 9:59 PM · ZFS