Piteball
/
android_kernel_google_msm
mirror of https://github.com/followmsi/android_kernel_google_msm.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

mm: change initial readahead window size calculation 

Change the logic which determines the initial readahead window size
such that for small requests (one page) the initial window size
will be x4 the size of the original request, regardless of the
VM_MAX_READAHEAD value. This prevents a rapid ramp-up
that could be caused due to increasing VM_MAX_READAHEAD.

Change-Id: I93d59c515d7e6c6d62348790980ff7bd4f434997
Signed-off-by: Lee Susman <lsusman@codeaurora.org>
This commit is contained in:
Lee Susman 2013-04-08 13:09:48 +03:00 committed by Zhao Wei Liew
parent c8ad3a7446
commit b91dba25fc
1 changed files with 3 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
mm/readahead.c
View File

@ -261,6 +261,8 @@ unsigned long ra_submit(struct file_ra_state *ra,
/*
* Set the initial window size, round to next power of 2 and square
* Small size is not dependant on max value - only a one-page read is regarded
* as small.
* for small size, x 4 for medium, and x 2 for large
* for 128k (32 page) max ra
* 1-8 page = 32k initial, > 8 page = 128k initial
@ -269,7 +271,7 @@ static unsigned long get_init_ra_size(unsigned long size, unsigned long max)
{
unsigned long newsize = roundup_pow_of_two(size);
if (newsize <= max / 32)
if (newsize <= 1)
newsize = newsize * 4;
else if (newsize <= max / 4)
newsize = newsize * 2;