02-15-2016, 11:26 AM | #1 |
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Using swap on a KT
On a KT (B00F - fw-5.3.7.3), 256Mbyte Ram, 4Gbyte eMMC ::
Using the system feature that /var/local is always mounted; either in 'main' or 'diags'. Setup to use 1/4 of /var/local for a system swap file. Over ssh (or telnet or serial port or from kTerm) - Code:
[root@kindle root]# cd /var/local [root@kindle local]# df . Filesystem 1K-blocks Used Available Use% Mounted on /dev/mmcblk0p3 31729 13083 17008 43% /var/local Code:
[root@kindle local]# echo $((1024*1024*8/4096)) 2048 Code:
[root@kindle local]# dd if=/dev/zero of=swap bs=4096 count=2048 2048+0 records in 2048+0 records out 8388608 bytes (8.0MB) copied, 0.186354 seconds, 42.9MB/s Code:
[root@kindle local]# mkswap ./swap Setting up swapspace version 1, size = 8384 kB no label, UUID=7b04d237-2476-4b2c-8b7b-0a5b58bf3006 Its use by the system is controlled by the swapon and swapoff commands. Code:
[root@kindle local]# swapon ./swap [root@kindle local]# free total used free shared buffers cached Mem: 255660 248608 7052 0 30308 85580 -/+ buffers/cache: 132720 122940 Swap: 7852 0 7852 Code:
[root@kindle local]# free total used free shared buffers cached Mem: 255660 247056 8604 0 22084 80048 -/+ buffers/cache: 144924 110736 Swap: 7852 2068 5784 Then close Kindle User's Guide Code:
[root@kindle local]# swapon -s Filename Type Size Used Priority /var/local/swap file 7852 2056 -1 [root@kindle local]# df . Filesystem 1K-blocks Used Available Use% Mounted on /dev/mmcblk0p3 31729 21306 8785 71% /var/local Even using only 2Mbyte of file space for the swap file reduces the kernel's page management workload. To the end-user, the appearent change is a more responsive Kindle. Since the above steps do not make an addition to /etc/fstab, the use of the swap file will 'go away' with the next re-boot. That is: the 'swapon /var/local/swap' command needs to re-issued after each reboot (the normal system shutdown will take care of the 'swapoff' process). When (IF) I get the spare time, I'll create a KUAL extension button (set) to let the non-technical user deal with all of the above. Note 1: If your 'main' system chokes by running out of space on /var/local - just re-boot into 'diags' and remove the /var/local/swap file. Note 2: Other directions you find may say to put the swap file in user storage. Not a good idea, because the Kernel can't access user storage when it is exported as mass storage over USB. And the Kernel really, really does not like to have the backing store of its swap file suddenly disappear. Note 3: The KT is the earliest Kindle with a large enough /var/local partition to make the above practical. Last edited by knc1; 02-15-2016 at 11:31 AM. |
02-15-2016, 12:11 PM | #2 |
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What about /mnt/base-us ?
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02-15-2016, 12:25 PM | #3 |
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I tried that - it seems that the fuse driver gets confused in some way (I ended up with two file type signatures on mmcblk0p4).
The '7th gen' devices are running a series 3.0.x kernel, not the 2.6.x kernel of earlier devices. So changes in internal behavior can be expected. I can always try again - perhaps I did something wrong when testing. And, I did not test on the KT (kern-2.6.x), only the PW-3 (kern-3.0.x). Last edited by knc1; 02-15-2016 at 12:29 PM. |
02-15-2016, 12:31 PM | #4 |
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Alternatively, here's a good excuse to play with the partition tables.
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02-15-2016, 01:18 PM | #5 | |
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Quote:
Code:
[root@kindle root]# cat /proc/self/mountinfo 13 1 179:1 / / ro,noatime,nodiratime - ext3 /dev/root ro,barrier=0,data=writeback 11 13 0:3 / /proc rw,nosuid,nodev,noexec,relatime - proc none rw 12 13 0:11 / /sys rw,nosuid,nodev,noexec,relatime - sysfs none rw 14 13 0:12 / /dev rw,relatime - tmpfs tmpfs rw,mode=755 15 14 0:13 / /dev/shm rw,relatime - tmpfs tmpfs rw 16 14 0:9 / /dev/pts rw,relatime - devpts devpts rw,gid=5,mode=620 17 13 0:14 / /var rw,relatime - tmpfs tmpfs rw,size=32768k 18 13 7:2 / /usr/share/X11/xkb ro,noatime,nodiratime - cramfs /dev/loop/2 ro 19 13 7:3 / /usr/java/lib/fonts ro,noatime,nodiratime - cramfs /dev/loop/3 ro 20 13 7:4 / /etc/kdb.src ro,noatime,nodiratime - cramfs /dev/loop/4 ro 21 13 7:5 / /usr/lib/locale ro,noatime,nodiratime - cramfs /dev/loop/5 ro 22 13 7:6 / /usr/share/keyboard ro,noatime,nodiratime - cramfs /dev/loop/6 ro 23 17 179:3 / /var/local rw,relatime - ext3 /dev/mmcblk0p3 rw,errors=continue,barrier=0,data=writeback 25 13 0:15 / /mnt/us rw,nosuid,nodev,noatime - fuse.fsp fsp rw,user_id=0,group_id=0,allow_other 24 13 7:0 / /mnt/base-us rw,noexec,noatime,nodiratime - vfat /dev/loop/0 rw,fmask=0000,dmask=0000,allow_utime=0022,codepage=cp437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro [root@kindle root]# losetup /dev/loop/1 losetup: /dev/loop/1: No such device or address Code:
[root@kindle root]# cat /proc/self/mountinfo 13 1 179:1 / / ro,noatime,nodiratime - ext3 /dev/root ro,barrier=0,data=writeback 11 13 0:3 / /proc rw,nosuid,nodev,noexec,relatime - proc none rw 12 13 0:11 / /sys rw,nosuid,nodev,noexec,relatime - sysfs none rw 14 13 0:12 / /dev rw,relatime - tmpfs tmpfs rw,mode=755 15 14 0:13 / /dev/shm rw,relatime - tmpfs tmpfs rw 16 14 0:9 / /dev/pts rw,relatime - devpts devpts rw,gid=5,mode=620 17 13 0:14 / /var rw,relatime - tmpfs tmpfs rw,size=32768k 18 13 7:2 / /usr/share/X11/xkb ro,noatime,nodiratime - cramfs /dev/loop/2 ro 19 13 7:3 / /usr/java/lib/fonts ro,noatime,nodiratime - cramfs /dev/loop/3 ro 20 13 7:4 / /etc/kdb.src ro,noatime,nodiratime - cramfs /dev/loop/4 ro 21 13 7:5 / /usr/lib/locale ro,noatime,nodiratime - cramfs /dev/loop/5 ro 22 13 7:6 / /usr/share/keyboard ro,noatime,nodiratime - cramfs /dev/loop/6 ro 23 17 179:3 / /var/local rw,relatime - ext3 /dev/mmcblk0p3 rw,errors=continue,barrier=0,data=writeback 25 13 0:15 / /mnt/us rw,nosuid,nodev,noatime - fuse.fsp fsp rw,user_id=0,group_id=0,allow_other [root@kindle root]# losetup /dev/loop/0 /dev/loop/0: 8192 /dev/mmcblk0p4 [root@kindle root]# losetup /dev/loop/1 losetup: /dev/loop/1: No such device or address [root@kindle root]# ls -la /mnt/us drwxrwxrwx 2 root root 1024 Apr 15 2015 . drwxrwxr-x 8 root root 1024 Apr 15 2015 .. Note also that /mnt/base-us (which gets un-mounted) is still in-use by the device-to-device translation in the VFS layers. I am fairly sure that kernel 2.6.x did not support device-to-device translation. @NiLJe: note - Code:
[root@kindle root]# r=$(cat /proc/self/mountinfo | grep '/dev/root') ; set $(echo $r) ; echo $3 179:1 179:2 == 'diags' At least until Lab126 changes the partition order on the eMMC. |
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02-16-2016, 12:54 AM | #6 |
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Actually, I was pondering the idea of repartitioning the userstore, making a swap partition that isn't exported over USB.
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02-16-2016, 12:56 AM | #7 |
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02-16-2016, 01:13 AM | #8 |
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I also remember it was done, but I was hoping someone else would remember where! And how.
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02-16-2016, 02:09 AM | #9 |
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I can give the parts of the chore I know of -
The eMMC at its base address has a DOS HD format disk label (mbr area not used). During boot, the address, size and alignment of partitions 1, 2, and 3 are checked. Note: Partition 1 **DOES NOT** start immediately following the partition table, there is a 16Mbyte gap (at least on the 4Gbyte machines, haven't checked the 2Gbyte machines yet). The address and alignment of partition 4 is checked, the size is set to match the remainder of the eMMC. At the start address of partition 4 is another DOS, HD format disk label. (yes, each partition can have its own partition table, but you will have a hell of a time finding it in the MS documents (it is, or was, in there). ??? I don't recall what things are tested about the sub-partition. ??? Only the first partition table entry is used. (you want to add a partition 2). The partition table (1), partition 4 is mounted with an 8192 byte offset, placing the mbr area and (sub-) partition table (2) **OUTSIDE** of the fuse layer. THAT is the reason for the initial /dev/loop/0 layer - losetup can start at an offset. Although FAT-32 can be re-sized, I don't know if the fuse layer would follow the change in size. (You have to shrink the first (and only) partition to have room for the second.) If trying this myself, I would first (try) to free all use of t1p4:t2p1 (how you like that abbreviation?) that is 'covered' by the fuse layer. I am guessing from this point on - Remove the kernel gadget module - Shut down the fuse layer - un-mount /mnt/us and /dev/loop/0 (or /dev/loop0 depending on kernel version) - un-mount /mnt/base-us if it is still there (???) - re-size the FAT-32 first partition of the second level partition table - re-size the first partition of the second level partition table - The above two re-size operations are so the system doesn't decide some of the system required contents of USB mass storage are missing and re-build everything you just did. create a second partition in the second level partition table - re-mount everything you un-mounted - start everything you had to stop - re-load the kernel modules you had to un-load - Hope the fuse layer stays within the new confines of the smaller first partition - Make use of the new second partition as desired. The exact details of that procedure is left as a student exercise. Next Morning Edit: A whole lot of that would be simplified by doing the work from 'diags' - Last edited by knc1; 02-16-2016 at 09:30 AM. |
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