On Apr 05, 2009 23:45 -0700, Michael Rubin wrote: > Anyone have any comments? Or historical reasons? We operate with some > constrained memory situations, and were wondering if a patch to move > from kmalloc to vmalloc would be well received. On 32-bit machines vmalloc space is tiny, and in all cases vmalloc performance sucks, so traditionally very little kernel allocation is done with vmalloc. For one-off allocations like per-fs it is probably OK to change them to vmalloc. > On Wed, Mar 11, 2009 at 7:32 AM, Curt Wohlgemuth <curtw@xxxxxxxxxx> wrote: > > I've been running various tests of ext4 partitions lately, and have > > found that with very low memory situations, I'm getting intermittent > > mount failures due to ENOMEM from ext4_mb_init() and > > ext4_fill_flex_info() . Here's a typical dmesg from the latter: > > > > EXT4-fs: not enough memory for 8198 flex groups > > EXT4-fs: unable to initialize flex_bg meta info! > > > > This is from a kzalloc() call of size ~64k . I think the > > ext4_mb_init() calls to kmalloc() and alloc_percpu() are even smaller. > > > > I was wondering why all the code in ext4 (and ext[23], for that > > matter) uses kmalloc() and friends instead of vmalloc(), at least > > where it's safe; is it just for performance reasons? > > > > I've seen the above errors when I do a mount -a, causing several > > partitions to be mounted; I can usually mount the failed ones by hand > > right afterwards, but this is a big difference for us, in our > > environment, compared to, say, ext2 partitions. > > > > Thanks, > > Curt > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
