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author | ivoras <ivoras@FreeBSD.org> | 2010-08-09 22:22:46 +0000 |
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committer | ivoras <ivoras@FreeBSD.org> | 2010-08-09 22:22:46 +0000 |
commit | fa067e3c3039de4e253b44dc547cbf0f9f9fb3f8 (patch) | |
tree | 8b6c4b89b7402fa14af0b66ac3a5ff97c5ad7b5d /sys/kern | |
parent | 6328a1bf234ed2d7887025aa36af52c854711c18 (diff) | |
download | FreeBSD-src-fa067e3c3039de4e253b44dc547cbf0f9f9fb3f8.zip FreeBSD-src-fa067e3c3039de4e253b44dc547cbf0f9f9fb3f8.tar.gz |
Elaborate on how hirunningspace was chosen.
Diffstat (limited to 'sys/kern')
-rw-r--r-- | sys/kern/vfs_bio.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c index 34f7acb..fe9b189 100644 --- a/sys/kern/vfs_bio.c +++ b/sys/kern/vfs_bio.c @@ -622,8 +622,11 @@ bufinit(void) /* * Note: The 16 MB upper limit for hirunningspace was chosen - * arbitrarily and may need further tuning. The lower 1 MB - * limit is the historical upper limit for hirunningspace. + * arbitrarily and may need further tuning. It corresponds to + * 128 outstanding write IO requests (if IO size is 128 KiB), + * which fits with many RAID controllers' tagged queing limits. + * The lower 1 MB limit is the historical upper limit for + * hirunningspace. */ hirunningspace = lmax(lmin(roundup(hibufspace / 64, MAXBSIZE), 16 * 1024 * 1024), 1024 * 1024); |