prstInstall()

The prstInstall() function is used by the bootstrap program to check whether:

• there are RAM blocks already occupied by persistent memory devices that must be registred (tagged) as allocated

• there are requests for additional RAM blocks to be allocated for new persistent memory devices

Typically, during a cold boot, prstInstall() does nothing because there are no persistent memory devices occupying or requesting RAM blocks. During the first hot boot, creation of the first persistent memory device can be required. Subsequently, during the second hot boot, the first memory device would already be registered and another memory device can request RAM block allocation.

Example 3-10 is prstInstall() source code provided in kernel/snippet/nucleus/boot_tools/prstInstall.c.

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Example 3-9 prstInstall()

    void
prstInstall()
{
    int i;

    RamDesc* ram = &bootConf->ramAllocator;
    RebootDesc* rd = bootConf->rebootDesc;

    /*
     * Tag existing persistent memory as allocated
     */
    for (i = 0; i < rd->hot.prstMem.numChunks; ++i) {
        PrstChunk* chunk = &rd->hot.prstMem.chunks[i];
        ASSERT(CEILING2(chunk->size, PAGE_SIZE_f) == chunk->size);
        if (chunk->status & PRST_CHUNK_ALLOCATED) {
            ram_tag(ram, chunk->paddr, (PhSize) chunk->size, PH_RAM_ALLOCATED);
        }
    }

    /*
     * Extend persistent memory
     */
    for (i = 0; i < rd->hot.prstMem.numChunks; ++i) {
        PrstChunk* chunk = &rd->hot.prstMem.chunks[i];
        ASSERT(CEILING2(chunk->size, PAGE_SIZE_f) == chunk->size);
        if (!(chunk->status & PRST_CHUNK_ALLOCATED)) {
            if (!ram_alloc(ram, &chunk->paddr, (PhSize) chunk->size, 
                           PAGE_SIZE_f)) {
                printf ("can't allocate 0x%x bytes of persistent memory\n", 
                        chunk->size);
                ASSERT(0);
            } else {
                chunk->status |= PRST_CHUNK_ALLOCATED;
            }
        }
    }
}

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