From e23aaf450de733044a74bc95528f728478b61c2a Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Mon, 16 Oct 2023 10:41:55 -0700 Subject: xfs: invert the realtime summary cache In commit 355e3532132b ("xfs: cache minimum realtime summary level"), I added a cache of the minimum level of the realtime summary that has any free extents. However, it turns out that the _maximum_ level is more useful for upcoming optimizations, and basically equivalent for the existing usage. So, let's change the meaning of the cache to be the maximum level + 1, or 0 if there are no free extents. For example, if the cache contains: {0, 4} then there are no free extents starting in realtime bitmap block 0, and there are no free extents larger than or equal to 2^4 blocks starting in realtime bitmap block 1. The cache is a loose upper bound, so there may or may not be free extents smaller than 2^4 blocks in realtime bitmap block 1. Signed-off-by: Omar Sandoval Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/xfs/libxfs/xfs_rtbitmap.c | 6 +++--- fs/xfs/xfs_mount.h | 6 +++--- fs/xfs/xfs_rtalloc.c | 31 +++++++++++++++++++------------ 3 files changed, 25 insertions(+), 18 deletions(-) (limited to 'fs/xfs') diff --git a/fs/xfs/libxfs/xfs_rtbitmap.c b/fs/xfs/libxfs/xfs_rtbitmap.c index 9f806af4f720..b332ab490a48 100644 --- a/fs/xfs/libxfs/xfs_rtbitmap.c +++ b/fs/xfs/libxfs/xfs_rtbitmap.c @@ -495,10 +495,10 @@ xfs_rtmodify_summary_int( xfs_suminfo_t val = xfs_suminfo_add(args, infoword, delta); if (mp->m_rsum_cache) { - if (val == 0 && log == mp->m_rsum_cache[bbno]) - mp->m_rsum_cache[bbno]++; - if (val != 0 && log < mp->m_rsum_cache[bbno]) + if (val == 0 && log + 1 == mp->m_rsum_cache[bbno]) mp->m_rsum_cache[bbno] = log; + if (val != 0 && log >= mp->m_rsum_cache[bbno]) + mp->m_rsum_cache[bbno] = log + 1; } xfs_trans_log_rtsummary(args, infoword); if (sum) diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h index d8769dc5f6dd..9cd1d570d24d 100644 --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h @@ -101,9 +101,9 @@ typedef struct xfs_mount { /* * Optional cache of rt summary level per bitmap block with the - * invariant that m_rsum_cache[bbno] <= the minimum i for which - * rsum[i][bbno] != 0. Reads and writes are serialized by the rsumip - * inode lock. + * invariant that m_rsum_cache[bbno] > the maximum i for which + * rsum[i][bbno] != 0, or 0 if rsum[i][bbno] == 0 for all i. + * Reads and writes are serialized by the rsumip inode lock. */ uint8_t *m_rsum_cache; struct xfs_mru_cache *m_filestream; /* per-mount filestream data */ diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c index d5b6be45755f..6bde64584a37 100644 --- a/fs/xfs/xfs_rtalloc.c +++ b/fs/xfs/xfs_rtalloc.c @@ -54,14 +54,19 @@ xfs_rtany_summary( int log; /* loop counter, log2 of ext. size */ xfs_suminfo_t sum; /* summary data */ - /* There are no extents at levels < m_rsum_cache[bbno]. */ - if (mp->m_rsum_cache && low < mp->m_rsum_cache[bbno]) - low = mp->m_rsum_cache[bbno]; + /* There are no extents at levels >= m_rsum_cache[bbno]. */ + if (mp->m_rsum_cache) { + high = min(high, mp->m_rsum_cache[bbno] - 1); + if (low > high) { + *stat = 0; + return 0; + } + } /* * Loop over logs of extent sizes. */ - for (log = low; log <= high; log++) { + for (log = high; log >= low; log--) { /* * Get one summary datum. */ @@ -82,9 +87,9 @@ xfs_rtany_summary( */ *stat = 0; out: - /* There were no extents at levels < log. */ - if (mp->m_rsum_cache && log > mp->m_rsum_cache[bbno]) - mp->m_rsum_cache[bbno] = log; + /* There were no extents at levels > log. */ + if (mp->m_rsum_cache && log + 1 < mp->m_rsum_cache[bbno]) + mp->m_rsum_cache[bbno] = log + 1; return 0; } @@ -887,12 +892,14 @@ xfs_alloc_rsum_cache( xfs_extlen_t rbmblocks) /* number of rt bitmap blocks */ { /* - * The rsum cache is initialized to all zeroes, which is trivially a - * lower bound on the minimum level with any free extents. We can - * continue without the cache if it couldn't be allocated. + * The rsum cache is initialized to the maximum value, which is + * trivially an upper bound on the maximum level with any free extents. + * We can continue without the cache if it couldn't be allocated. */ - mp->m_rsum_cache = kvzalloc(rbmblocks, GFP_KERNEL); - if (!mp->m_rsum_cache) + mp->m_rsum_cache = kvmalloc(rbmblocks, GFP_KERNEL); + if (mp->m_rsum_cache) + memset(mp->m_rsum_cache, -1, rbmblocks); + else xfs_warn(mp, "could not allocate realtime summary cache"); } -- cgit v1.2.3