remotefilelog: replace repack lock to solve race condition
2c74337e6483 reduced the probability of race-conditions when starting
background repack and prefetch and we saw the difference in our CI instance
with all failures disappearing except one where one call to waitonrepack seems
to returns too early.
I'm not sure what exactly goes wrong but I realized that while the prefetch
operation uses a standard Mercurial lock, the repack operation is using a
custom lock based on `fcntl.flock` on available platforms. As `extutil.flock`
fallback on traditional Mercurial locks on other platforms and the tests are
stable on my laptop, our CI environment and GCC112, I'm sending this patch to
standardize the behavior across environments.
Differential Revision: https://phab.mercurial-scm.org/D6844
#require no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
# devel.remotefilelog.ensurestart: reduce race condition with
# waiton{repack/prefetch}
$ cat >> $HGRCPATH <<EOF
> [devel]
> remotefilelog.ensurestart=True
> EOF
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ echo z > z
$ hg commit -qAm x
$ echo x2 > x
$ echo y > y
$ hg commit -qAm y
$ echo w > w
$ rm z
$ hg commit -qAm w
$ hg bookmark foo
$ cd ..
# clone the repo
$ hgcloneshallow ssh://user@dummy/master shallow --noupdate
streaming all changes
2 files to transfer, 776 bytes of data
transferred 776 bytes in * seconds (*/sec) (glob)
searching for changes
no changes found
# Set the prefetchdays config to zero so that all commits are prefetched
# no matter what their creation date is. Also set prefetchdelay config
# to zero so that there is no delay between prefetches.
$ cd shallow
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> prefetchdays=0
> prefetchdelay=0
> EOF
$ cd ..
# prefetch a revision
$ cd shallow
$ hg prefetch -r 0
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ hg cat -r 0 x
x
# background prefetch on pull when configured
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> pullprefetch=bookmark()
> backgroundprefetch=True
> EOF
$ hg strip tip
saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/6b4b6f66ef8c-b4b8bdaf-backup.hg (glob)
$ clearcache
$ hg pull
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
updating bookmark foo
added 1 changesets with 0 changes to 0 files
new changesets 6b4b6f66ef8c
(run 'hg update' to get a working copy)
prefetching file contents
$ sleep 0.5
$ hg debugwaitonprefetch >/dev/null 2>%1
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/ef95c5376f34698742fe34f315fd82136f8f68c0
$TESTTMP/hgcache/master/95/cb0bfd2977c761298d9624e4b4d4c72a39974a/076f5e2225b3ff0400b98c92aa6cdf403ee24cca
$TESTTMP/hgcache/master/af/f024fe4ab0fece4091de044c58c9ae4233383a/bb6ccd5dceaa5e9dc220e0dad65e051b94f69a2c
$TESTTMP/hgcache/repos
# background prefetch with repack on pull when configured
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> backgroundrepack=True
> EOF
$ hg strip tip
saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/6b4b6f66ef8c-b4b8bdaf-backup.hg (glob)
$ clearcache
$ hg pull
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
updating bookmark foo
added 1 changesets with 0 changes to 0 files
new changesets 6b4b6f66ef8c
(run 'hg update' to get a working copy)
prefetching file contents
$ sleep 0.5
$ hg debugwaitonprefetch >/dev/null 2>%1
$ sleep 0.5
$ hg debugwaitonrepack >/dev/null 2>%1
$ sleep 0.5
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/packs/6e8633deba6e544e5f8edbd7b996d6e31a2c42ae.histidx
$TESTTMP/hgcache/master/packs/6e8633deba6e544e5f8edbd7b996d6e31a2c42ae.histpack
$TESTTMP/hgcache/master/packs/8ce5ab3745465ab83bba30a7b9c295e0c8404652.dataidx
$TESTTMP/hgcache/master/packs/8ce5ab3745465ab83bba30a7b9c295e0c8404652.datapack
$TESTTMP/hgcache/repos
# background prefetch with repack on update when wcprevset configured
$ clearcache
$ hg up -r 0
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0
$TESTTMP/hgcache/master/39/5df8f7c51f007019cb30201c49e884b46b92fa/69a1b67522704ec122181c0890bd16e9d3e7516a
$TESTTMP/hgcache/repos
$ hg up -r 1
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
2 files fetched over 2 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> bgprefetchrevs=.::
> EOF
$ clearcache
$ hg up -r 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
* files fetched over * fetches - (* misses, 0.00% hit ratio) over *s (glob)
$ sleep 1
$ hg debugwaitonprefetch >/dev/null 2>%1
$ sleep 1
$ hg debugwaitonrepack >/dev/null 2>%1
$ sleep 1
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histidx
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histpack
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.dataidx
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.datapack
$TESTTMP/hgcache/repos
# Ensure that file 'w' was prefetched - it was not part of the update operation and therefore
# could only be downloaded by the background prefetch
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407:
w:
Node Delta Base Delta Length Blob Size
bb6ccd5dceaa 000000000000 2 2
Total: 2 2 (0.0% bigger)
x:
Node Delta Base Delta Length Blob Size
ef95c5376f34 000000000000 3 3
1406e7411862 ef95c5376f34 14 2
Total: 17 5 (240.0% bigger)
y:
Node Delta Base Delta Length Blob Size
076f5e2225b3 000000000000 2 2
Total: 2 2 (0.0% bigger)
z:
Node Delta Base Delta Length Blob Size
69a1b6752270 000000000000 2 2
Total: 2 2 (0.0% bigger)
# background prefetch with repack on commit when wcprevset configured
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> bgprefetchrevs=0::
> EOF
$ clearcache
$ find $CACHEDIR -type f | sort
$ echo b > b
$ hg commit -qAm b
* files fetched over 1 fetches - (* misses, 0.00% hit ratio) over *s (glob)
$ hg bookmark temporary
$ sleep 1
$ hg debugwaitonprefetch >/dev/null 2>%1
$ sleep 1
$ hg debugwaitonrepack >/dev/null 2>%1
$ sleep 1
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histidx
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histpack
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.dataidx
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.datapack
$TESTTMP/hgcache/repos
# Ensure that file 'w' was prefetched - it was not part of the commit operation and therefore
# could only be downloaded by the background prefetch
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407:
w:
Node Delta Base Delta Length Blob Size
bb6ccd5dceaa 000000000000 2 2
Total: 2 2 (0.0% bigger)
x:
Node Delta Base Delta Length Blob Size
ef95c5376f34 000000000000 3 3
1406e7411862 ef95c5376f34 14 2
Total: 17 5 (240.0% bigger)
y:
Node Delta Base Delta Length Blob Size
076f5e2225b3 000000000000 2 2
Total: 2 2 (0.0% bigger)
z:
Node Delta Base Delta Length Blob Size
69a1b6752270 000000000000 2 2
Total: 2 2 (0.0% bigger)
# background prefetch with repack on rebase when wcprevset configured
$ hg up -r 2
3 files updated, 0 files merged, 3 files removed, 0 files unresolved
(leaving bookmark temporary)
$ clearcache
$ find $CACHEDIR -type f | sort
$ hg rebase -s temporary -d foo
rebasing 3:58147a5b5242 "b" (temporary tip)
saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/58147a5b5242-c3678817-rebase.hg
3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
$ sleep 1
$ hg debugwaitonprefetch >/dev/null 2>%1
$ sleep 1
$ hg debugwaitonrepack >/dev/null 2>%1
$ sleep 1
# Ensure that file 'y' was prefetched - it was not part of the rebase operation and therefore
# could only be downloaded by the background prefetch
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407:
w:
Node Delta Base Delta Length Blob Size
bb6ccd5dceaa 000000000000 2 2
Total: 2 2 (0.0% bigger)
x:
Node Delta Base Delta Length Blob Size
ef95c5376f34 000000000000 3 3
1406e7411862 ef95c5376f34 14 2
Total: 17 5 (240.0% bigger)
y:
Node Delta Base Delta Length Blob Size
076f5e2225b3 000000000000 2 2
Total: 2 2 (0.0% bigger)
z:
Node Delta Base Delta Length Blob Size
69a1b6752270 000000000000 2 2
Total: 2 2 (0.0% bigger)
# Check that foregound prefetch with no arguments blocks until background prefetches finish
$ hg up -r 3
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ clearcache
$ hg prefetch --repack
waiting for lock on prefetching in $TESTTMP/shallow held by process * on host * (glob) (?)
got lock after * seconds (glob) (?)
(running background incremental repack)
* files fetched over 1 fetches - (* misses, 0.00% hit ratio) over *s (glob) (?)
$ sleep 0.5
$ hg debugwaitonrepack >/dev/null 2>%1
$ sleep 0.5
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histidx
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histpack
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.dataidx
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.datapack
$TESTTMP/hgcache/repos
# Ensure that files were prefetched
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407:
w:
Node Delta Base Delta Length Blob Size
bb6ccd5dceaa 000000000000 2 2
Total: 2 2 (0.0% bigger)
x:
Node Delta Base Delta Length Blob Size
ef95c5376f34 000000000000 3 3
1406e7411862 ef95c5376f34 14 2
Total: 17 5 (240.0% bigger)
y:
Node Delta Base Delta Length Blob Size
076f5e2225b3 000000000000 2 2
Total: 2 2 (0.0% bigger)
z:
Node Delta Base Delta Length Blob Size
69a1b6752270 000000000000 2 2
Total: 2 2 (0.0% bigger)
# Check that foreground prefetch fetches revs specified by '. + draft() + bgprefetchrevs + pullprefetch'
$ clearcache
$ hg prefetch --repack
waiting for lock on prefetching in $TESTTMP/shallow held by process * on host * (glob) (?)
got lock after * seconds (glob) (?)
(running background incremental repack)
* files fetched over 1 fetches - (* misses, 0.00% hit ratio) over *s (glob) (?)
$ sleep 0.5
$ hg debugwaitonrepack >/dev/null 2>%1
$ sleep 0.5
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histidx
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histpack
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.dataidx
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.datapack
$TESTTMP/hgcache/repos
# Ensure that files were prefetched
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407:
w:
Node Delta Base Delta Length Blob Size
bb6ccd5dceaa 000000000000 2 2
Total: 2 2 (0.0% bigger)
x:
Node Delta Base Delta Length Blob Size
ef95c5376f34 000000000000 3 3
1406e7411862 ef95c5376f34 14 2
Total: 17 5 (240.0% bigger)
y:
Node Delta Base Delta Length Blob Size
076f5e2225b3 000000000000 2 2
Total: 2 2 (0.0% bigger)
z:
Node Delta Base Delta Length Blob Size
69a1b6752270 000000000000 2 2
Total: 2 2 (0.0% bigger)
# Test that if data was prefetched and repacked we dont need to prefetch it again
# It ensures that Mercurial looks not only in loose files but in packs as well
$ hg prefetch --repack
(running background incremental repack)