Allow swap_pager_putpages() to allocate one block at a time.
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Authored by markj on Feb 19 2020, 8:41 PM.

Details

Reviewers

alc
dougm
kib
jeff

Commits

rS358261: Allow swap_pager_putpages() to allocate one block at a time.

Summary

Alan points out that the minimum allocation size of 4 blocks is an old
policy that came with the "new" swap pager in r42957. Since then the
blist allocator has gotten better at minimizing fragmentation; for
example, with r349777 it can return a range that spans multiple leaves.
When swap space is close to being exhaused, the minimum of 4 blocks most
likely exacerbates things. Reduce it to 1.

Test Plan

Peter reported no problems.

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Build Status

Buildable 29502
Build 27372: arc lint + arc unit

Event Timeline

markj created this revision.Feb 19 2020, 8:41 PM

Harbormaster completed remote builds in B29502: Diff 68559.Feb 19 2020, 8:41 PM

markj edited the summary of this revision. (Show Details)Feb 19 2020, 8:43 PM

markj edited the test plan for this revision. (Show Details)

markj added reviewers: alc, dougm, kib, jeff.

kib accepted this revision.Feb 20 2020, 1:39 PM

This revision is now accepted and ready to land.Feb 20 2020, 1:39 PM

alc accepted this revision.Feb 22 2020, 9:30 PM

This change makes the second argument to swp_pager_getswapspace redundant. A future change might as well eliminate it.

In D23763#522914, @dougm wrote:

This change makes the second argument to swp_pager_getswapspace redundant. A future change might as well eliminate it.

Indeed. I didn't bother since that change doesn't really simplify swp_pager_getswapspace() at all, but it seems reasonable to me.

Closed by commit rS358261: Allow swap_pager_putpages() to allocate one block at a time. (authored by markj). · Explain WhyFeb 23 2020, 6:00 PM

This revision was automatically updated to reflect the committed changes.

markj added a commit: rS358261: Allow swap_pager_putpages() to allocate one block at a time..

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