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nova: optimize unmap path

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Directly unmap memory range instead of looking first it up and then unmap it.

Prerequisite for #675
This commit is contained in:
Alexander Boettcher 2013-02-27 15:58:58 +01:00 committed by Norman Feske
parent 974c5442c6
commit b2d92f3d94
2 changed files with 47 additions and 81 deletions
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82
base-nova/src/core/include/nova_util.h
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@ -2,6 +2,7 @@
* \brief NOVA-specific convenience functions
* \author Norman Feske
* \author Sebastian Sumpf
* \author Alexander Boettcher
* \date 2010-01-19
*/
@ -86,6 +87,20 @@ inline int map_local_one_to_one(Nova::Utcb *utcb, Nova::Crd crd) {
return map_local(utcb, crd, crd, true); }
/**
* Find least significant set bit in value
*/
inline unsigned char
lsb_bit(unsigned long const &value, unsigned char const shift = 0)
{
unsigned long const scan = value >> shift;
if (scan == 0) return 0;
unsigned char pos = __builtin_ctzl(scan);
unsigned char res = shift ? pos + shift : pos;
return res;
}
/**
* Remap pages in the local address space
*
@ -123,19 +138,10 @@ inline int map_local(Nova::Utcb *utcb,
*/
addr_t const common_bits = from_curr | to_curr;
/*
* Find highest clear bit in 'diff', starting from the least
* significant candidate. We can skip all bits lower then
* 'get_page_size_log2()' because they are not relevant as flexpage
* size (and are always zero).
*/
size_t order = get_page_size_log2();
for (; order < 32 && !(common_bits & (1UL << order)); order++);
/*
* Look if flexpage fits into both 'from' and 'to' address range
*/
/* find least set bit in common bits */
size_t order = lsb_bit(common_bits, get_page_size_log2());
/* look if flexpage fits into both 'from' and 'to' address range */
if ((from_end - from_curr) < (1UL << order))
order = log2(from_end - from_curr);
@ -165,48 +171,42 @@ inline int map_local(Nova::Utcb *utcb,
* \param utcb UTCB of the main thread
* \param start local virtual address
* \param num_pages number of pages to unmap
* \param self unmap from this pd or solely from other pds
*/
inline void unmap_local(Nova::Utcb *utcb,
Genode::addr_t start,
Genode::size_t num_pages)
inline void unmap_local(Nova::Utcb *utcb, Genode::addr_t start,
Genode::size_t num_pages,
bool const self = true)
{
if (verbose_local_map)
Genode::printf("::unmap_local: from %lx, %zd pages\n",
start, num_pages);
using namespace Nova;
using namespace Genode;
Rights const rwx(true, true, true);
Genode::addr_t end = start + (num_pages << get_page_size_log2()) - 1;
Genode::addr_t base = start >> get_page_size_log2();
while (true) {
Nova::Mem_crd crd(start >> 12, 32, rwx);
Nova::lookup(crd);
if (start & (get_page_size() - 1)) {
PERR("unmap failed - unaligned address specified");
return;
}
if (!crd.is_null()) {
if (verbose_local_map)
PINF("Unmapping local: range 0x%lx+0x%zx", base, num_pages);
if (verbose_local_map)
PINF("Unmapping local: %08lx base: %lx order: %lx size: %lx is null: %d",
start, crd.base(), crd.order(),
(0x1000UL << crd.order()), crd.is_null());
Nova::Rights const rwx = Nova::Rights(true, true, true);
unmap_local(crd, true);
while (num_pages) {
unsigned char const base_bit = lsb_bit(base);
unsigned char const order_bit = min(log2(num_pages), 31U);
unsigned char const order = min(order_bit, base_bit);
start = (crd.base() << 12) /* base address of mapping */
+ (0x1000 << crd.order()); /* size of mapping */
} else {
Mem_crd const crd(base, order, rwx);
/* This can happen if the region has never been touched */
if (verbose_local_map)
PINF("Unmapping local: 0x%lx+0x%lx", crd.base(),
1UL << crd.order());
if (verbose_local_map)
PINF("Nothing mapped at local: %08lx", start);
unmap_local(crd, self);
start += 0x1000;
}
if (start > end)
return;
num_pages -= 1UL << order;
base += 1UL << order;
}
}

46
base-nova/src/core/rm_session_support.cc
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@ -12,53 +12,19 @@
* under the terms of the GNU General Public License version 2.
*/
/* Genode includes */
#include <base/printf.h>
#include <base/ipc_pager.h>
/* core includes */
#include <rm_session_component.h>
#include <nova_util.h>
using namespace Genode;
static const bool verbose = false;
void Rm_client::unmap(addr_t core_local_base, addr_t virt_base, size_t size)
void Rm_client::unmap(addr_t core_local_base, addr_t, size_t size)
{
addr_t const core_local_end = core_local_base + (size - 1);
off_t const core_to_virt = virt_base - core_local_base;
using namespace Nova;
Nova::Rights rwx(true, true, true);
Utcb * utcb = reinterpret_cast<Utcb *>(Genode::Thread_base::myself()->utcb());
while (true) {
Nova::Mem_crd crd(core_local_base >> 12, 32, rwx);
Nova::lookup(crd);
if (!crd.is_null()) {
if (verbose)
PINF("Unmapping local: %08lx virt: %08lx base: %lx order: %lx size: %lx is null: %d",
core_local_base, core_local_base + core_to_virt, crd.base(), crd.order(),
(0x1000UL << crd.order()), crd.is_null());
unmap_local(crd, false);
core_local_base = (crd.base() << 12) /* base address of mapping */
+ (0x1000 << crd.order()); /* size of mapping */
} else {
/* this can happen if the region has never been touched */
if (verbose)
PINF("Nothing mapped at local: %08lx virt: %08lx",
core_local_base, core_local_base + core_to_virt);
core_local_base += 0x1000;
}
if (core_local_base > core_local_end)
return;
}
unmap_local(utcb, trunc_page(core_local_base),
(round_page(core_local_base + size) -
trunc_page(core_local_base)) / get_page_size(), false);
}