Hi

Could someone please post a code sample or explain how to create a
lookaside list and use it, and when to use the paged or non paged
version of it?

Thanks!

There are examples in the DDK samples. With the latest DDK take a look at
src\general\pcidrv for a good sample. You decide to use paged versus
non-paged the same way you decide for any other memory allocation, is the
memory from the list going to be accessed in cases where the driver is
running at IRQL DISPATCH_LEVEL or higher? If so use non-paged, otherwise
use paged.


--
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting
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"Omer" <Omerb99@gmail.com> wrote in message
news:1116319561.751772.125220@o13g2000cwo.googlegr oups.com...

"Omer" wrote:
Recently there was some interesting detail on this in the OSR NTDEV list.
Check it if you're subscribed.

--PA

you would use a lookaside list when you make frequent allocations and frees
of memory that are all of the same size (or if not of the same size, if you
can round up to size where you do not burn alot of unused memory).

d

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"Omer" <Omerb99@gmail.com> wrote in message
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So, lookaside list is more like a "heap manager" then a list, right ?

No.

On frees, it preserves the blocks on the hot-reserve list, and just
detaches it back on future allocations. If the hot-reserve is over - it falls
back to usual ExAllocatePoolWithTag.

--
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
maxim@storagecraft.com
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"sharon sahar" <sharon.sahar@gmail.com> wrote in message
news:1116348662.108923.167940@g47g2000cwa.googlegr oups.com...

so i use a single or duoble linked list and instead of allocating each
block with ExAllocatePool() i use the lookaside mechanism?

Lookaside lists are not lists, they are an allocation mechanism for
allocating and freeing multiple of the same size block. If you have needs
for a dynamic environment of the same size blocks, where you do both
allocates and frees then this is a good mechanism.


--
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting
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"Omer" <Omerb99@gmail.com> wrote in message
news:1116415232.219696.279560@g47g2000cwa.googlegr oups.com...

the list part of the name refers to a list of free blocks w/in the
lookaside. this means that when you free a block back to the lookaside
list, instead of calling ExFreePool, the lookaside list inserts the block
into an internal list. when you go to allocate another block, it can pull
blocks from this list instead of calling ExAllocatePool. Furthermore, the
system knows about these lookaside lists. When the system is low on
resources, it can go into the lookaside list and grab some of the free
blocks. So, in the end a lookaside list is helpful for your perf and plays
nice with the rest of the system.

d

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"Don Burn" <burn@stopspam.acm.org> wrote in message
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Thanks alot to you all !
Your replies were very helpful, especially the last one !