This changes the way we calculate how much space to reserve for the
pHyp dump. Currently we reserve 256MB only. With this change, the
code first checks to see if an amount has been specified on the boot
command line with the "phyp_dump_reserve_size" option, and if so, uses
that much.
Otherwise it computes 5% of total ram and rounds it down to a multiple
of 256MB, and uses the larger of that or 256MB.
This is for large systems with a lot of memory (10GB or more). The
aim is to have more space available for the kernel on reboot on
machines with more resources. Although the dump will be collected
pretty fast and the memory released really early on allowing the
machine to have the full memory available, this alleviates any issues
that can be caused by having way too little memory on very very large
systems during those few minutes.
Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This adds /sys/kernel/phyp_dump_active so that kdump init scripts may
look for it and take appropriate action if this file is found. This
file is only created when phyp_dump has been registered.
Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This adds a kernel command line option "phyp_dump", which takes a 0/1
value for disabling/ enabling phyp_dump at boot time. Kdump can use
this on cmdline (phyp_dump=0) to disable phyp-dump during boot when
enabling itself. This will ensure only one dumping mechanism is active
at any given time.
Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This tracks the size freed. For now it does a simple rudimentary
calculation of the ranges freed. The idea is to keep it simple at the
external shell script level and send in large chunks for now.
Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This adds routines to
a. invalidate dump
b. calculate region that is reserved and needs to be freed. This is
exported through sysfs interface.
Unregister has been removed for now as it wasn't being used.
Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Set up the actual dump header, register it with the hypervisor.
Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Check to see if there actually is data from a previously
crashed kernel waiting. If so, allow user-space tools to
grab the data (by reading /proc/kcore). When user-space
finishes dumping a section, it must release that memory
by writing to sysfs. For example,
echo "0x40000000 0x10000000" > /sys/kernel/release_region
will release 256MB starting at the 1GB. The released memory
becomes free for general use.
Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>
Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Initial patch for reserving memory in early boot, and freeing it
later. If the previous boot had ended with a crash, the reserved
memory would contain a copy of the crashed kernel data.
Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Manish Ahuja