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| author | Eric Blake <eblake@redhat.com> | 2011-04-27 15:41:54 -0600 |
|---|---|---|
| committer | Eric Blake <eblake@redhat.com> | 2011-04-28 14:18:52 -0600 |
| commit | 7cbc494f7cc150886b741e2af5051685d818f89c (patch) | |
| tree | 941060113eabcc615c3b10ef7d8d76f46407a88a | |
| parent | 8585ce2ff5698c650ba5d5e3bb99763654ad62e8 (diff) | |
| download | gnulib-7cbc494f7cc150886b741e2af5051685d818f89c.tar.gz | |
utimecmp: drop dependency on xmalloc
utimecmp's only use of malloc was for a cache; we can always bypass
the cache in low memory, and thus avoid dragging in xalloc-die.
* lib/utimecmp.c (utimecmp): Work even if hash table cache fails
due to memory pressure.
* modules/utimecmp (Depends-on): Drop xalloc.
Signed-off-by: Eric Blake <eblake@redhat.com>
| -rw-r--r-- | ChangeLog | 7 | ||||
| -rw-r--r-- | lib/utimecmp.c | 58 | ||||
| -rw-r--r-- | modules/utimecmp | 1 |
3 files changed, 48 insertions, 18 deletions
@@ -1,3 +1,10 @@ +2011-04-28 Eric Blake <eblake@redhat.com> + + utimecmp: drop dependency on xmalloc + * lib/utimecmp.c (utimecmp): Work even if hash table cache fails + due to memory pressure. + * modules/utimecmp (Depends-on): Drop xalloc. + 2011-04-27 Eric Blake <eblake@redhat.com> getcwd: fix mingw bugs diff --git a/lib/utimecmp.c b/lib/utimecmp.c index 356763ff61..c0f6713e3b 100644 --- a/lib/utimecmp.c +++ b/lib/utimecmp.c @@ -33,7 +33,6 @@ #include "stat-time.h" #include "utimens.h" #include "verify.h" -#include "xalloc.h" #ifndef MAX # define MAX(a, b) ((a) > (b) ? (a) : (b)) @@ -122,7 +121,9 @@ utimecmp (char const *dst_name, /* Things to watch out for: The code uses a static hash table internally and is not safe in the - presence of signals, multiple threads, etc. + presence of signals, multiple threads, etc. However, memory pressure + that prevents use of the hash table is not fatal - we just fall back + to redoing the computations on every call in that case. int and long int might be 32 bits. Many of the calculations store numbers up to 2 billion, and multiply by 10; they have to avoid @@ -143,12 +144,13 @@ utimecmp (char const *dst_name, { /* Look up the time stamp resolution for the destination device. */ - /* Hash table for devices. */ + /* Hash table for caching information learned about devices. */ static Hash_table *ht; /* Information about the destination file system. */ static struct fs_res *new_dst_res; - struct fs_res *dst_res; + struct fs_res *dst_res = NULL; + struct fs_res tmp_dst_res; /* Time stamp resolution in nanoseconds. */ int res; @@ -163,24 +165,46 @@ utimecmp (char const *dst_name, if (src_s <= dst_s - 2) return 1; + /* Try to do a hash lookup, but fall back to stack variables and + recomputation on low memory situations. */ if (! ht) ht = hash_initialize (16, NULL, dev_info_hash, dev_info_compare, free); - if (! new_dst_res) + if (ht) { - new_dst_res = xmalloc (sizeof *new_dst_res); - new_dst_res->resolution = 2 * BILLION; - new_dst_res->exact = false; - } - new_dst_res->dev = dst_stat->st_dev; - dst_res = hash_insert (ht, new_dst_res); - if (! dst_res) - xalloc_die (); + if (! new_dst_res) + { + new_dst_res = malloc (sizeof *new_dst_res); + if (!new_dst_res) + goto low_memory; + new_dst_res->resolution = 2 * BILLION; + new_dst_res->exact = false; + } + new_dst_res->dev = dst_stat->st_dev; + dst_res = hash_insert (ht, new_dst_res); + if (! dst_res) + goto low_memory; - if (dst_res == new_dst_res) + if (dst_res == new_dst_res) + { + /* NEW_DST_RES is now in use in the hash table, so allocate a + new entry next time. */ + new_dst_res = NULL; + } + } + else { - /* NEW_DST_RES is now in use in the hash table, so allocate a - new entry next time. */ - new_dst_res = NULL; + low_memory: + if (ht) + { + tmp_dst_res.dev = dst_stat->st_dev; + dst_res = hash_lookup (ht, &tmp_dst_res); + } + if (!dst_res) + { + dst_res = &tmp_dst_res; + dst_res->resolution = 2 * BILLION; + dst_res->exact = false; + } } res = dst_res->resolution; diff --git a/modules/utimecmp b/modules/utimecmp index 7be906b219..a3160c8d54 100644 --- a/modules/utimecmp +++ b/modules/utimecmp @@ -11,7 +11,6 @@ hash stat-time time utimens -xalloc intprops lstat stdbool |