On Tuesday 26 June 2001 01:59, Rik van Riel wrote:

On Tue, 26 Jun 2001, Roger Larsson wrote:

quoted

What about

   unsigned int vm_pgfails /* failed alloc attempts, in pages (not calls)
*/

What would that represent ?

How often __alloc_pages() exits without allocating anything?

Yes, failed allocs  [Call it vm_pgalloc_fails ?]

quoted

maybe even a

   unsigned int vm_pgallocs /* alloc attempts, in pages */

for sanity checking - should be the sum of several other combinations...

Sounds like a nice idea.

Let this and vm_pgalloc_fails work together,

at __alloc_pages entry (always done) account in vm_pgallocs
at failed exit account in vm_pgallocs_failed

quoted

Should memory zone be used as dimension?

Useful for allocations I guess, but it may be too confusing
if we do this for all statistics... OTOH...

Using order as another dimension could also be interesting...
Something like this?

vm_pgallocs[
	order < MAX_ACCOUNT_ORDER ? order : MAX_ACCOUNT_ORDER][
	gfp_mask & GFP_ZONEMASK] += (1 << order)

Or even simpler (assuming MAX_ACCOUNT_ORDER == 1)

vm_pgallocs[!!order][gfp_mask & GFP_ZONEMASK] += (1 << order)

BTW, why is GFP_ZONEMASK 0xf when MAX_NR_ZONES is 3 ? (i.e. 0..2)

/RogerL

-- 
Roger Larsson
Skelleftea
Sweden
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