Replace the last use of sbrk() in the tree with mmap().
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Authored by brooks on Jan 21 2016, 1:15 AM.

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emaste
jilles
cem
jhb

Commits

rS294523: Replace the last non-optional use of sbrk() in the tree with mmap().

Summary

All gmon want's is a region of memory without the overhead of malloc().
Just mapping a page with mmap is an easy way to accomplish this.

Obtained from: CheriBSD (bf33e1e70b368ababde74aa3ac70d108c8a52c69)
Sponsored by: DARPA, AFRL

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rS FreeBSD src repository - subversion

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Event Timeline

brooks updated this revision to Diff 12528.Jan 21 2016, 1:15 AM

brooks retitled this revision from to Replace the last use of sbrk() in the tree with mmap()..

brooks updated this object.

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

brooks added a reviewer: jilles.

Herald added a subscriber: imp. · View Herald TranscriptJan 21 2016, 1:15 AM

emaste added a subscriber: emaste.Jan 21 2016, 1:21 AM

Egads, what madness lurks in the depths of libc.

This revision is now accepted and ready to land.Jan 21 2016, 1:22 AM

cem accepted this revision.Jan 21 2016, 1:37 AM

cem added a reviewer: cem.

cem added a subscriber: cem.

cem added inline comments.

lib/libc/gmon/gmon.c
111 ↗	(On Diff #12528)	What was minbrk used for?

brooks added inline comments.Jan 21 2016, 1:41 AM

lib/libc/gmon/gmon.c
111 ↗	(On Diff #12528)	It sets a floor on the break value. AFACT it's a hack that prevents the program from accidentally freeing the gmon memory. See lib/libc/*/sys/brk.S.

emaste accepted this revision.Jan 21 2016, 2:47 AM

emaste added a reviewer: emaste.

Closed by commit rS294523: Replace the last non-optional use of sbrk() in the tree with mmap(). (authored by brooks). · Explain WhyJan 21 2016, 6:17 PM

This revision was automatically updated to reflect the committed changes.

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head/

lib/

libc/

gmon/

gmon.c

15 lines

Diff 12567

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Replace the last use of sbrk() in the tree with mmap().ClosedPublicActions