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cxl: Fix allocating a minimum of 2 pages for the SPA

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The Scheduled Process Area is allocated dynamically with enough pages to
fit at least as many processes as the AFU descriptor indicated. Since
the calculation is non-trivial, it does this by calculating how many
processes could fit in an allocation of a given order, and increasing
that order until it can fit enough processes or hits the maximum
supported size.

Currently, it will start this search using a SPA of 2 pages instead of
1. This can waste a page of memory if the AFU's maximum number of
supported processes was small enough to fit in one page.

Fix the algorithm to start the search at 1 page.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Ian Munsie 2016-06-29 22:16:26 +10:00 committed by Michael Ellerman
parent 49e9c99f47
commit 2224b6719b
1 changed files with 1 additions and 1 deletions
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2
drivers/misc/cxl/native.c
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@ -189,7 +189,7 @@ int cxl_alloc_spa(struct cxl_afu *afu)
unsigned spa_size;
/* Work out how many pages to allocate */
afu->native->spa_order = 0;
afu->native->spa_order = -1;
do {
afu->native->spa_order++;
spa_size = (1 << afu->native->spa_order) * PAGE_SIZE;