Bug 151351 – Reserved VM pool established in r187125 is likely too conservative

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Michael Saboff]

In change set 187125, a 25% reserve of the VM allocation pool was established.  The platform with smallest VM pool is 16MB and a reserve of 25% is 4MB.  Given that the reserve is for "compile must succeed compilations", which are typically for OSR stub generation and other contingent code, this seems a little large.

The proposal is to reduce the reserve from 25% to 15%.

<rdar://problem/22910951>

[Michael Saboff]

Created attachment 265680 [details]
Patch

[Filip Pizlo]

Comment on attachment 265680 [details]
Patch

I seem to recall 0.25 being necessary to fix a bug.

[Michael Saboff]

Created attachment 265688 [details]
Updated patch

After discussing this with Phil and Geoff, we think it would be safer to limit this change to ARM 32 bit only.

[Filip Pizlo]

Comment on attachment 265688 [details]
Updated patch

Nice.

[Filip Pizlo]

Comment on attachment 265688 [details]
Updated patch

View in context: https://bugs.webkit.org/attachment.cgi?id=265688&action=review

> Source/JavaScriptCore/ChangeLog:8
> +        Reduce the VM allocation reserved pool from 25% to 15% for ARM.

I'd say "ARM32" in the changelog, to make sure that if someone reads this, they don't think you also reduced it for ARM64.

[Michael Saboff]

(In reply to comment #5)
> Comment on attachment 265688 [details]
> Updated patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=265688&action=review
> 
> > Source/JavaScriptCore/ChangeLog:8
> > +        Reduce the VM allocation reserved pool from 25% to 15% for ARM.
> 
> I'd say "ARM32" in the changelog, to make sure that if someone reads this,
> they don't think you also reduced it for ARM64.

Will do.

[Michael Saboff]

Created attachment 265696 [details]
Patch for landing

Added feedback from prior reviewed patch.

[WebKit Commit Bot]

Comment on attachment 265696 [details]
Patch for landing

Clearing flags on attachment: 265696

Committed r192527: <http://trac.webkit.org/changeset/192527>