diff options
| -rw-r--r-- | usr/src/uts/common/sys/fs/tmp.h | 30 |
1 files changed, 17 insertions, 13 deletions
diff --git a/usr/src/uts/common/sys/fs/tmp.h b/usr/src/uts/common/sys/fs/tmp.h index 641d76f7d9..d9d3075c59 100644 --- a/usr/src/uts/common/sys/fs/tmp.h +++ b/usr/src/uts/common/sys/fs/tmp.h @@ -67,22 +67,26 @@ enum de_op { DE_CREATE, DE_MKDIR, DE_LINK, DE_RENAME }; /* direnter ops */ enum dr_op { DR_REMOVE, DR_RMDIR, DR_RENAME }; /* dirremove ops */ /* - * tmpfs_minfree is the amount (in pages) of anonymous memory that tmpfs leaves - * free for the rest of the system. In antiquity, this number could be + * tmpfs_minfree is the amount (in pages) of anonymous memory that tmpfs + * leaves free for the rest of the system. In antiquity, this number could be * relevant on a system-wide basis, as physical DRAM was routinely exhausted; * however, in more modern times, the relative growth of DRAM with respect to - * application footprint means that this number is only likely to become factor - * in a virtualized OS environment (e.g., a zone) -- and even then only when - * DRAM and swap have both been capped low to allow for maximum tenancy. In - * general, this number should be configured to be the largest value that is - * still smaller than the smallest practical value for memory + swap for a - * zone. (As of this writing, that's about 128MB.) This can be tuned up with - * little consequence (other than generating ENOSPC for tmpfs writes) -- but - * caution should be used if tuning this value too low (e.g., less than a - * megabyte), as it increases the likelihood that tmpfs consumption alone will - * be able to induce application-level memory allocation failure. + * application footprint means that this number is only likely to become + * factor in a virtualized OS environment (e.g., a zone) -- and even then only + * when DRAM and swap have both been capped low to allow for maximum tenancy. + * TMPMINFREE -- the value from which tmpfs_minfree is derived -- should + * therefore be configured to a value that is roughly the smallest practical + * value for memory + swap minus the largest reasonable size for tmpfs in such + * a configuration. As of this writing, the smallest practical memory + swap + * configuration is 128MB, and it seems reasonable to allow tmpfs to consume + * no more than seven-eighths of this, yielding a TMPMINFREE of 16MB. Care + * should be exercised in changing this: tuning this value too high will + * result in spurious ENOSPC errors in tmpfs in small zones (a problem that + * can induce cascading failure surprisingly often); tuning this value too low + * will result in tmpfs consumption alone to alone induce application-level + * memory allocation failure. */ -#define TMPMINFREE 128 * 1024 * 1024 /* 128 Megabytes */ +#define TMPMINFREE 16 * 1024 * 1024 /* 16 Megabytes */ extern size_t tmpfs_minfree; /* Anonymous memory in pages */ |