Brian, can you take a look at this?

When debugging the UsedPct histograms we noticed the 96%-100% bucket was hit more often that we thought was possible and it turns out if the logic is such that if IsCorrupt() is true then it sets free to 0 and will hit that bucket. I think that case should be logged separately.

Logging the corrupted case sounds like a good idea.

I'll also remove the setting of "free" to zero, at least for histogram reporting, to avoid any future confusion.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cc51fdc84d9c63e481dabbcdb7710d26e685940e

commit cc51fdc84d9c63e481dabbcdb7710d26e685940e
Author: bcwhite <bcwhite@chromium.org>
Date: Wed Jan 25 16:45:25 2017

Create 'errors' histogram for failures.

BUG= 671649 

Review-Url: https://codereview.chromium.org/2635303002
Cr-Commit-Position: refs/heads/master@{#446037}

[modify] https://crrev.com/cc51fdc84d9c63e481dabbcdb7710d26e685940e/base/metrics/persistent_memory_allocator.cc
[modify] https://crrev.com/cc51fdc84d9c63e481dabbcdb7710d26e685940e/base/metrics/persistent_memory_allocator.h
[modify] https://crrev.com/cc51fdc84d9c63e481dabbcdb7710d26e685940e/tools/metrics/histograms/extract_histograms.py
[modify] https://crrev.com/cc51fdc84d9c63e481dabbcdb7710d26e685940e/tools/metrics/histograms/histograms.xml

Is this change applicable to all OSes or any specific OS?

Your change meets the bar and is auto-approved for M57. Please go ahead and merge the CL to branch 2987 manually. Please contact milestone owner if you have questions.
Owners: amineer@(clank), cmasso@(bling), ketakid@(cros), govind@(desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5cfb1802e5196854a6829e47d186e2246c5c4700

commit 5cfb1802e5196854a6829e47d186e2246c5c4700
Author: Brian White <bcwhite@chromium.org>
Date: Mon Jan 30 21:58:52 2017

Create 'errors' histogram for failures.

BUG= 671649 

Review-Url: https://codereview.chromium.org/2635303002
Cr-Commit-Position: refs/heads/master@{#446037}
(cherry picked from commit cc51fdc84d9c63e481dabbcdb7710d26e685940e)

Review-Url: https://codereview.chromium.org/2662083002 .
Cr-Commit-Position: refs/branch-heads/2987@{#192}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}

[modify] https://crrev.com/5cfb1802e5196854a6829e47d186e2246c5c4700/base/metrics/persistent_memory_allocator.cc
[modify] https://crrev.com/5cfb1802e5196854a6829e47d186e2246c5c4700/base/metrics/persistent_memory_allocator.h
[modify] https://crrev.com/5cfb1802e5196854a6829e47d186e2246c5c4700/tools/metrics/histograms/extract_histograms.py
[modify] https://crrev.com/5cfb1802e5196854a6829e47d186e2246c5c4700/tools/metrics/histograms/histograms.xml