diff options
Diffstat (limited to 'user')
| -rw-r--r-- | user/Maksym_Planeta.mdwn | 41 |
1 files changed, 30 insertions, 11 deletions
diff --git a/user/Maksym_Planeta.mdwn b/user/Maksym_Planeta.mdwn index 707507a7..6f9bf3ec 100644 --- a/user/Maksym_Planeta.mdwn +++ b/user/Maksym_Planeta.mdwn @@ -13,16 +13,6 @@ License|/fdl]]."]]"""]] ## mach-defpager - <tschwinge>: 1. On every system there is a ``default pager'' (mach-defpager). That one is responsible - for all ``anonymous memory''. For example, when you do malloc(10 MiB), and then there is memory pressure, - this 10 MiB memory region is backed by the default pager, whose job then is it to provide the backing store for this. - <tschwinge>: This is what commonly would be known as a swap partition. - <tschwinge>: And this is also the way tmpfs works (as I understand it). - <tschwinge>: malloc(10 MiB) can also be mmap(MAP_ANONYMOUS, 10 MIB); that's the same, essentially. - <tschwinge>: Now, for ext2fs or any other disk-based file system, this is different: - <tschwinge>: The ext2fs translator implements its own backing store, namely it accesses the disk for storing - changed file content, or to read in data from disk if a new file is opened. - [[defpager|http://www.bddebian.com:8888/~hurd-web/user/Maksym_Planeta/#defpager81111]] ## Steps @@ -41,6 +31,21 @@ License|/fdl]]."]]"""]] Symlinks behavior: [[links|http://www.bddebian.com:8888/~hurd-web/user/Maksym_Planeta/#links81111]] + 8.11.11 Symlinks work. + +4. Control of used space by tmpfs. + + TODO: Make tmpfs use not more space than it was allowed. + +5. Thread safety. + + TODO: During execution tmpfs hangs in random places. The most possible is variant is deadlocks, + because nothing was undertaken for thread safety. + +6. After sometime of inactivity tmpfs exits. + + TODO: Find out why and correct this. + #Debugging To debug tmpfs, using libraries from "$PWD"/lib and trace rpc: @@ -49,6 +54,7 @@ To debug tmpfs, using libraries from "$PWD"/lib and trace rpc: LD_LIBRARY_PATH="$PWD"/lib gdb tmpfs/tmpfs 698 For debugging ext2fs: + settrans --create --active ramdisk0 /hurd/storeio -T copy zero:32M && \ /sbin/mkfs.ext2 -F -b 4096 ramdisk0 && \ settrans --active --orphan ramdisk0 /usr/bin/env LD_LIBRARY_PATH="$PWD"/lib utils/rpctrace -I /usr/share/msgids/ \ @@ -76,6 +82,20 @@ For debugging ext2fs: (10:32:35) braunr: baz -> bar ### defpager<a id="defpager81111"/> + + earlier: + <tschwinge>: 1. On every system there is a ``default pager'' (mach-defpager). That one is responsible + for all ``anonymous memory''. For example, when you do malloc(10 MiB), and then there is memory pressure, + this 10 MiB memory region is backed by the default pager, whose job then is it to provide the backing store for this. + <tschwinge>: This is what commonly would be known as a swap partition. + <tschwinge>: And this is also the way tmpfs works (as I understand it). + <tschwinge>: malloc(10 MiB) can also be mmap(MAP_ANONYMOUS, 10 MIB); that's the same, essentially. + <tschwinge>: Now, for ext2fs or any other disk-based file system, this is different: + <tschwinge>: The ext2fs translator implements its own backing store, namely it accesses the disk for storing + changed file content, or to read in data from disk if a new file is opened. + + ... + (10:36:14) mcsim: who else uses defpager besides tmpfs and kernel? (10:36:27) braunr: normally, nothing directly (10:37:04) mcsim: than why tmpfs should use defpager? @@ -89,7 +109,6 @@ For debugging ext2fs: (10:41:27) braunr: anonymous memory uses swap space as its backing store too (10:43:47) braunr: but be aware that this part of the vm system is known to have deficiencies (10:44:14) braunr: which is why all mach based implementations have rewritten their default pager - (10:44:41) youpi: ArneBab: the intro is already in in my qemu image (10:45:11) mcsim: what kind of deficiencies? (10:45:16) braunr: bugs (10:45:39) braunr: and design issues, making anonymous memory fragmentation horrible |