If I 'systemctl restart packagekit' the new process consumes about 25MiB for at least 5 minutes. And then seemingly after a repository cache update, this grows > 300 MiB and isn't ever released,  it only grows from there.

I guess that's the DnfContext, although I'm not really sure. 25MiB seems like more what I'd expect for packagekid, although even that seems an order of magnitude more than what I'd want. Does the RSS blow up if you select a different backend? e.g. sudo /usr/libexec/packagekitd --backend=dummy

root        9384  0.0  0.1 262320  9072 pts/1    S+   10:43   0:00 sudo /usr/libexec/packagekitd --backend=dummy
root        9386  0.0  0.1 538404 11052 pts/1    Sl+  10:43   0:00 /usr/libexec/packagekitd --backend=dummy

So, quite a lot less.

For what it's worth, this is not a new problem, I see it in Fedora 31 also. 

PackageKit-1.1.12-11.fc31.x86_64

Clean install, reboot, and within 5 minutes of uptime and following completion of g-i-s:

root        1095 64.1 15.5 1296972 625480 ?      Ssl  11:17   3:29 /usr/libexec/packagekitd

That's 15% of installed RAM with our recommended system requirements, and 30% with the minimum system requirement.

Both of these are on Fedora 31, but the behavior is the same on Fedora 32 and 33. These are taken 10 minutes uptime.

# cat /proc/1095/status
Name:	packagekitd
Umask:	0022
State:	S (sleeping)
Tgid:	1095
Ngid:	0
Pid:	1095
PPid:	1
TracerPid:	0
Uid:	0	0	0	0
Gid:	0	0	0	0
FDSize:	128
Groups:	 
NStgid:	1095
NSpid:	1095
NSpgid:	1095
NSsid:	1095
VmPeak:	 1446396 kB
VmSize:	 1277444 kB
VmLck:	       0 kB
VmPin:	       0 kB
VmHWM:	  719632 kB
VmRSS:	  624760 kB
RssAnon:	  601776 kB
RssFile:	   22984 kB
RssShmem:	       0 kB
VmData:	  668180 kB
VmStk:	     132 kB
VmExe:	     208 kB
VmLib:	   21468 kB
VmPTE:	    1428 kB
VmSwap:	    2900 kB
HugetlbPages:	       0 kB
CoreDumping:	0
THP_enabled:	1
Threads:	3
SigQ:	4/15567
SigPnd:	0000000000000000
ShdPnd:	0000000000000000
SigBlk:	0000000000000000
SigIgn:	0000000000001000
SigCgt:	0000000180000002
CapInh:	0000000000000000
CapPrm:	0000003fffffffff
CapEff:	0000003fffffffff
CapBnd:	0000003fffffffff
CapAmb:	0000000000000000
NoNewPrivs:	0
Seccomp:	0
Speculation_Store_Bypass:	thread vulnerable
Cpus_allowed:	f
Cpus_allowed_list:	0-3
Mems_allowed:	00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000001
Mems_allowed_list:	0
voluntary_ctxt_switches:	4774
nonvoluntary_ctxt_switches:	12447



chris       1736  2.1  5.1 1327320 205368 ?      Sl   11:18   0:13 /usr/bin/gnome-software --gapplication-service

# cat /proc/1736/status
Name:	gnome-software
Umask:	0022
State:	S (sleeping)
Tgid:	1736
Ngid:	0
Pid:	1736
PPid:	1474
TracerPid:	0
Uid:	1000	1000	1000	1000
Gid:	1000	1000	1000	1000
FDSize:	256
Groups:	10 1000 
NStgid:	1736
NSpid:	1736
NSpgid:	1474
NSsid:	1474
VmPeak:	 1376496 kB
VmSize:	 1327320 kB
VmLck:	       0 kB
VmPin:	       0 kB
VmHWM:	  221896 kB
VmRSS:	  205368 kB
RssAnon:	  169184 kB
RssFile:	   35680 kB
RssShmem:	     504 kB
VmData:	  225644 kB
VmStk:	     132 kB
VmExe:	     576 kB
VmLib:	   37852 kB
VmPTE:	     628 kB
VmSwap:	       0 kB
HugetlbPages:	       0 kB
CoreDumping:	0
THP_enabled:	1
Threads:	4
SigQ:	0/15567
SigPnd:	0000000000000000
ShdPnd:	0000000000000000
SigBlk:	0000000000000000
SigIgn:	0000000000001000
SigCgt:	0000000180000000
CapInh:	0000000000000000
CapPrm:	0000000000000000
CapEff:	0000000000000000
CapBnd:	0000003fffffffff
CapAmb:	0000000000000000
NoNewPrivs:	0
Seccomp:	0
Speculation_Store_Bypass:	thread vulnerable
Cpus_allowed:	f
Cpus_allowed_list:	0-3
Mems_allowed:	00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000001
Mems_allowed_list:	0
voluntary_ctxt_switches:	15342
nonvoluntary_ctxt_switches:	1784

Checking back on F31 after 2 hours uptime, packagekitd is not running at all. And gnome-software is still running (in the background) consuming 210M. Let me know if these are possibly related, or if the gnome-software case needs a separate bug report.

F33 after 6 hours uptime. Terminal is the only application launched.

chris       2181  0.0  4.2 1115640 169824 ?      Sl   15:01   0:06 /usr/bin/gnome-software --gapplication-service
root        2381  0.2  8.8 1024596 353976 ?      Ssl  15:01   0:44 /usr/libexec/packagekitd

FWIW, on my Rawhide desktop that's been up for some time, packagekitd shows 1806M virt / 1230m res in htop. So yeah, a lot.

Same here. On a system low on RAM I disabled packagekitd for that reason – this is of course not what the Desktop designers want :-P

*** Bug 1867435 has been marked as a duplicate of this bug. ***

*** Bug 1857819 has been marked as a duplicate of this bug. ***

This message is a reminder that Fedora 33 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora 33 on 2021-11-30.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
Fedora 'version' of '33'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 33 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

This message is a reminder that Fedora 33 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora 33 on 2021-11-30.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
Fedora 'version' of '33'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 33 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

This message is a reminder that Fedora 33 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora 33 on 2021-11-30.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
Fedora 'version' of '33'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 33 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

at 1112M virt / 472M res on Rawhide RN. Still seems like a lot.

This bug appears to have been reported against 'rawhide' during the Fedora 36 development cycle.
Changing version to 36.

It's not as bad in F36, but 400M for a background program with file backed cache for exactly this purpose is too high still.

[root@f36 ~]# cat /proc/1068/smaps_rollup
55da85317000-7ffebc8b7000 ---p 00000000 00:00 0                          [rollup]
Rss:              187348 kB
Pss:              169682 kB
Pss_Anon:         163200 kB
Pss_File:           6482 kB
Pss_Shmem:             0 kB
Shared_Clean:      19116 kB
Shared_Dirty:          0 kB
Private_Clean:      5032 kB
Private_Dirty:    163200 kB
Referenced:       187348 kB
Anonymous:        163200 kB
LazyFree:              0 kB
AnonHugePages:         0 kB
ShmemPmdMapped:        0 kB
FilePmdMapped:         0 kB
Shared_Hugetlb:        0 kB
Private_Hugetlb:       0 kB
Swap:                  0 kB
SwapPss:               0 kB
Locked:                0 kB

On my Fedora 34 system, packagekitd will slowly leak memory, with multiple gigabytes consumed after a few days.   Swap ends up becoming very full, and the computer has problems with things being swapped in and out.  After several days this is a severe performance problem and requires a reboot. 

smem -s swap -r|less run as root shows packagekitd is using gigabytes of swap memory.

Systemctl stop packagekit will only return a relatively small amount of memory.  Only a reboot really fixes the memory leak.

Systemctl disable packagekit keeps packagekitd from running.  When this is done, the memory leak will not occur.   

I have had F34 installed on this computer for over a year and the behavior only started about a couple months ago.

FEDORA-2023-6c1c40d160 has been submitted as an update to Fedora 37. https://bodhi.fedoraproject.org/updates/FEDORA-2023-6c1c40d160

This message is a reminder that Fedora Linux 36 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora Linux 36 on 2023-05-16.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
'version' of '36'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, change the 'version' 
to a later Fedora Linux version. Note that the version field may be hidden.
Click the "Show advanced fields" button if you do not see it.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora Linux 36 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora Linux, you are encouraged to change the 'version' to a later version
prior to this bug being closed.

This should be addressed as of current Rawhide and F38, by https://src.fedoraproject.org/rpms/PackageKit/c/bd2bbf1a08ea2b887033b2a16a22e30615bb2a12?branch=f38 . we intentionally didn't backport that to F37 and earlier, though, as it's a fairly significant change.