Author: delphij
Date: Sun Apr 5 02:08:17 2020
New Revision: 359636
URL: https://svnweb.freebsd.org/changeset/base/359636
Log:
MFC r357609: MFV r357608: Limit memory usage in xz(1) instead of in tuklib.
Modified:
stable/12/contrib/xz/src/common/tuklib_physmem.c
stable/12/contrib/xz/src/xz/hardware.c
stable/12/contrib/xz/src/xz/xz.1
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/contrib/xz/src/common/tuklib_physmem.c
==============================================================================
--- stable/12/contrib/xz/src/common/tuklib_physmem.c Sun Apr 5 01:53:35
2020 (r359635)
+++ stable/12/contrib/xz/src/common/tuklib_physmem.c Sun Apr 5 02:08:17
2020 (r359636)
@@ -45,7 +45,6 @@
# include <sys/systemcfg.h>
#elif defined(TUKLIB_PHYSMEM_SYSCONF)
-# include <limits.h>
# include <unistd.h>
#elif defined(TUKLIB_PHYSMEM_SYSCTL)
@@ -146,16 +145,13 @@ tuklib_physmem(void)
#elif defined(TUKLIB_PHYSMEM_SYSCONF)
const long pagesize = sysconf(_SC_PAGESIZE);
const long pages = sysconf(_SC_PHYS_PAGES);
- if (pagesize != -1 && pages != -1) {
+ if (pagesize != -1 && pages != -1)
// According to docs, pagesize * pages can overflow.
// Simple case is 32-bit box with 4 GiB or more RAM,
// which may report exactly 4 GiB of RAM, and "long"
// being 32-bit will overflow. Casting to uint64_t
// hopefully avoids overflows in the near future.
ret = (uint64_t)pagesize * (uint64_t)pages;
- if (ret > SIZE_T_MAX)
- ret = SIZE_T_MAX;
- }
#elif defined(TUKLIB_PHYSMEM_SYSCTL)
int name[2] = {
Modified: stable/12/contrib/xz/src/xz/hardware.c
==============================================================================
--- stable/12/contrib/xz/src/xz/hardware.c Sun Apr 5 01:53:35 2020
(r359635)
+++ stable/12/contrib/xz/src/xz/hardware.c Sun Apr 5 02:08:17 2020
(r359636)
@@ -68,8 +68,38 @@ hardware_memlimit_set(uint64_t new_memlimit,
new_memlimit = (uint32_t)new_memlimit * total_ram / 100;
}
- if (set_compress)
+ if (set_compress) {
memlimit_compress = new_memlimit;
+
+#if SIZE_MAX == UINT32_MAX
+ // FIXME?
+ //
+ // When running a 32-bit xz on a system with a lot of RAM and
+ // using a percentage-based memory limit, the result can be
+ // bigger than the 32-bit address space. Limiting the limit
+ // below SIZE_MAX for compression (not decompression) makes
+ // xz lower the compression settings (or number of threads)
+ // to a level that *might* work. In practice it has worked
+ // when using a 64-bit kernel that gives full 4 GiB address
+ // space to 32-bit programs. In other situations this might
+ // still be too high, like 32-bit kernels that may give much
+ // less than 4 GiB to a single application.
+ //
+ // So this is an ugly hack but I will keep it here while
+ // it does more good than bad.
+ //
+ // Use a value less than SIZE_MAX so that there's some room
+ // for the xz program and so on. Don't use 4000 MiB because
+ // it could look like someone mixed up base-2 and base-10.
+ const uint64_t limit_max = UINT64_C(4020) << 20;
+
+ // UINT64_MAX is a special case for the string "max" so
+ // that has to be handled specially.
+ if (memlimit_compress != UINT64_MAX
+ && memlimit_compress > limit_max)
+ memlimit_compress = limit_max;
+#endif
+ }
if (set_decompress)
memlimit_decompress = new_memlimit;
Modified: stable/12/contrib/xz/src/xz/xz.1
==============================================================================
--- stable/12/contrib/xz/src/xz/xz.1 Sun Apr 5 01:53:35 2020
(r359635)
+++ stable/12/contrib/xz/src/xz/xz.1 Sun Apr 5 02:08:17 2020
(r359636)
@@ -1005,6 +1005,25 @@ instead of
until the details have been decided.
.RE
.IP ""
+For 32-bit
+.BR xz
+there is a special case: if the
+.I limit
+would be over
+.BR "4020\ MiB" ,
+the
+.I limit
+is set to
+.BR "4020\ MiB" .
+(The values
+.B 0
+and
+.B max
+aren't affected by this.
+A similar feature doesn't exist for decompression.)
+This can be helpful when a 32-bit executable has access
+to 4\ GiB address space while hopefully doing no harm in other situations.
+.IP ""
See also the section
.BR "Memory usage" .
.TP
_______________________________________________
svn-src-all@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
