From: Heiko Carstens <[email protected]>
[S390] Use diag260 for memory size detection.
Avoid the tprot loop if diag260 works and reports that there are no
holes in memory. The tprot instruction can lead to a significant delay
in the ipl process if the virtual guest has a lot of memory and the
host is under memory pressure.
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>
---
arch/s390/kernel/head64.S | 17 +++++++++++++++--
1 files changed, 15 insertions(+), 2 deletions(-)
diff -urpN linux-2.6/arch/s390/kernel/head64.S linux-2.6-patched/arch/s390/kernel/head64.S
--- linux-2.6/arch/s390/kernel/head64.S 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6-patched/arch/s390/kernel/head64.S 2006-12-04 14:50:55.000000000 +0100
@@ -70,7 +70,22 @@ startup_continue:
sgr %r5,%r5 # set src,length and pad to zero
mvcle %r2,%r4,0 # clear mem
jo .-4 # branch back, if not finish
+ # set program check new psw mask
+ mvc __LC_PGM_NEW_PSW(8),.Lpcmsk-.LPG1(%r13)
+ larl %r1,.Lslowmemdetect # set program check address
+ stg %r1,__LC_PGM_NEW_PSW+8
+ lghi %r1,0xc
+ diag %r0,%r1,0x260 # get memory size of virtual machine
+ cgr %r0,%r1 # different? -> old detection routine
+ jne .Lslowmemdetect
+ aghi %r1,1 # size is one more than end
+ larl %r2,memory_chunk
+ stg %r1,8(%r2) # store size of chunk
+ larl %r2,memory_size
+ stg %r1,0(%r2) # set memory size
+ j .Ldonemem
+.Lslowmemdetect:
l %r2,.Lrcp-.LPG1(%r13) # Read SCP forced command word
.Lservicecall:
stosm .Lpmask-.LPG1(%r13),0x01 # authorize ext interrupts
@@ -139,8 +154,6 @@ startup_continue:
.int 0x100000
.Lfchunk:
- # set program check new psw mask
- mvc __LC_PGM_NEW_PSW(8),.Lpcmsk-.LPG1(%r13)
#
# find memory chunks.
-
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