extern struct Saveanchor saveanchor; /* Aliged savearea anchor */
+struct Saveanchor backpocket; /* Emergency saveareas */
unsigned int debsave0 = 0; /* Debug flag */
unsigned int backchain = 0; /* Debug flag */
* processors. This represents the minimum number required to process a total system failure without
* destroying valuable and ever-so-handy system debugging information.
*
+ * We keep two global free lists (the savearea free pool and the savearea free list) and one local
+ * list per processor.
*
+ * The local lists are small and require no locked access. They are chained using physical addresses
+ * and no interruptions are allowed when adding to or removing from the list. Also known as the
+ * qfret list. This list is local to a processor and is intended for use only by very low level
+ * context handling code.
+ *
+ * The savearea free list is a medium size list that is globally accessible. It is updated
+ * while holding a simple lock. The length of time that the lock is held is kept short. The
+ * longest period of time is when the list is trimmed. Like the qfret lists, this is chained physically
+ * and must be accessed with translation and interruptions disabled. This is where the bulk
+ * of the free entries are located.
+ *
+ * The saveareas are allocated from full pages. A pool element is marked
+ * with an allocation map that shows which "slots" are free. These pages are allocated via the
+ * normal kernel memory allocation functions. Queueing is with physical addresses. The enqueue,
+ * dequeue, and search for free blocks is done under free list lock.
+ * only if there are empty slots in it.
+ *
+ * Saveareas that are counted as "in use" once they are removed from the savearea free list.
+ * This means that all areas on the local qfret list are considered in use.
+ *
+ * There are two methods of obtaining a savearea. The save_get function (which is also inlined
+ * in the low-level exception handler) attempts to get an area from the local qfret list. This is
+ * done completely without locks. If qfret is exahusted (or maybe just too low) an area is allocated
+ * from the savearea free list. If the free list is empty, we install the back pocket areas and
+ * panic.
+ *
+ * The save_alloc function is designed to be called by high level routines, e.g., thread creation,
+ * etc. It will allocate from the free list. After allocation, it will compare the free count
+ * to the target value. If outside of the range, it will adjust the size either upwards or
+ * downwards.
+ *
+ * If we need to shrink the list, it will be trimmed to the target size and unlocked. The code
+ * will walk the chain and return each savearea to its pool page. If a pool page becomes
+ * completely empty, it is dequeued from the free pool list and enqueued (atomic queue
+ * function) to be released.
+ *
+ * Once the trim list is finished, the pool release queue is checked to see if there are pages
+ * waiting to be released. If so, they are released one at a time.
+ *
+ * If the free list needed to be grown rather than shrunken, we will first attempt to recover
+ * a page from the pending release queue (built when we trim the free list). If we find one,
+ * it is allocated, otherwise, a page of kernel memory is allocated. This loops until there are
+ * enough free saveareas.
+ *
*/
+
+
/*
- * This routine allocates a save area. It checks if enough are available.
- * If not, it allocates upward to the target free count.
- * Then, it allocates one and returns it.
+ * Allocate our initial context save areas. As soon as we do this,
+ * we can take an interrupt. We do the saveareas here, 'cause they're guaranteed
+ * to be at least page aligned.
*/
+void savearea_init(vm_offset_t *addrx) {
-struct savearea *save_alloc(void) { /* Reserve a save area */
-
- kern_return_t retr;
- savectl *sctl; /* Previous and current save pages */
- vm_offset_t vaddr, paddr;
- struct savearea *newbaby;
-
- if(saveanchor.savecount <= (saveanchor.saveneed - saveanchor.saveneghyst)) { /* Start allocating if we drop too far */
- while(saveanchor.savecount < saveanchor.saveneed) { /* Keep adding until the adjustment is done */
-
-
- retr = kmem_alloc_wired(kernel_map, &vaddr, PAGE_SIZE); /* Find a virtual address to use */
-
- if(retr != KERN_SUCCESS) { /* Did we get some memory? */
- panic("Whoops... Not a bit of wired memory left for saveareas\n");
- }
-
- paddr = pmap_extract(kernel_pmap, vaddr); /* Get the physical */
-
- bzero((void *)vaddr, PAGE_SIZE); /* Clear it all to zeros */
- sctl = (savectl *)(vaddr+PAGE_SIZE-sizeof(savectl)); /* Point to the control area of the new page */
- sctl->sac_alloc = sac_empty; /* Mark all entries free */
- sctl->sac_vrswap = (unsigned int)vaddr ^ (unsigned int)paddr; /* Form mask to convert V to R and vice versa */
+ savearea_comm *savec, *savec2, *saveprev;
+ vm_offset_t save, save2, addr;
+ int i;
- sctl->sac_flags |= 0x0000EE00; /* (TEST/DEBUG) */
-
- if(!save_queue(paddr)) { /* Add the new ones to the free savearea list */
- panic("Arrgghhhh, time out trying to lock the savearea anchor during upward adjustment\n");
- }
- }
- }
- if (saveanchor.savecount > saveanchor.savemaxcount)
- saveanchor.savemaxcount = saveanchor.savecount;
+
+ saveanchor.savetarget = InitialSaveTarget; /* Initial target value */
+ saveanchor.saveinuse = 0; /* Number of areas in use */
- newbaby = save_get(); /* Get a savearea and return it */
- if(!((unsigned int)newbaby & 0xFFFFF000)) { /* Whoa... None left??? No, way, no can do... */
- panic("No saveareas?!?!?! No way! Can't happen! Nuh-uh... I'm dead, done for, kaput...\n");
- }
+ saveanchor.savefree = 0; /* Remember the start of the free chain */
+ saveanchor.savefreecnt = 0; /* Remember the length */
+ saveanchor.savepoolfwd = (unsigned int *)&saveanchor; /* Remember pool forward */
+ saveanchor.savepoolbwd = (unsigned int *)&saveanchor; /* Remember pool backward */
- return newbaby; /* Bye-bye baby... */
-
-}
+ addr = *addrx; /* Make this easier for ourselves */
+ save = addr; /* Point to the whole block of blocks */
/*
- * This routine releases a save area to the free queue. If after that, we have more than our maximum target,
- * we start releasing what we can until we hit the normal target.
+ * First we allocate the back pocket in case of emergencies
*/
+ for(i=0; i < 8; i++) { /* Initialize the back pocket saveareas */
-void save_release(struct savearea *save) { /* Release a save area */
-
- savectl *csave; /* The just released savearea block */
+ savec = (savearea_comm *)save; /* Get the control area for this one */
- save_ret(save); /* Return a savearea to the free list */
-
- if(saveanchor.savecount > (saveanchor.saveneed + saveanchor.saveposhyst)) { /* Start releasing if we have to many */
- csave = (savectl *)42; /* Start with some nonzero garbage */
- while((unsigned int)csave && (saveanchor.savecount > saveanchor.saveneed)) { /* Keep removing until the adjustment is done */
+ savec->sac_alloc = 0; /* Mark it allocated */
+ savec->sac_vrswap = 0; /* V=R, so the translation factor is 0 */
+ savec->sac_flags = sac_perm; /* Mark it permanent */
+ savec->sac_flags |= 0x0000EE00; /* Debug eyecatcher */
+ save_queue((savearea *)savec); /* Add page to savearea lists */
+ save += PAGE_SIZE; /* Jump up to the next one now */
- csave = save_dequeue(); /* Find and dequeue one that is all empty */
-
- if((unsigned int)csave & 1) { /* Did we timeout trying to get the lock? */
- panic("Arrgghhhh, time out trying to lock the savearea anchor during downward adjustment\n");
- return;
- }
-
- if((unsigned int)csave) kmem_free(kernel_map, (vm_offset_t) csave, PAGE_SIZE); /* Release the page if we found one */
- }
}
- return;
-
-}
-
-
-save_fake_zone_info(int *count, vm_size_t *cur_size, vm_size_t *max_size, vm_size_t *elem_size,
- vm_size_t *alloc_size, int *collectable, int *exhaustable)
-{
- *count = saveanchor.saveinuse;
- *cur_size = saveanchor.savecount * (PAGE_SIZE / 2);
- *max_size = saveanchor.savemaxcount * (PAGE_SIZE / 2);
- *elem_size = PAGE_SIZE / 2;
- *alloc_size = PAGE_SIZE;
- *collectable = 1;
- *exhaustable = 0;
-}
+ backpocket = saveanchor; /* Save this for emergencies */
/*
- * This routine prints the free savearea block chain for debugging.
+ * We've saved away the back pocket savearea info, so reset it all and
+ * now allocate for real
*/
+ saveanchor.savefree = 0; /* Remember the start of the free chain */
+ saveanchor.savefreecnt = 0; /* Remember the length */
+ saveanchor.saveadjust = 0; /* Set none needed yet */
+ saveanchor.savepoolfwd = (unsigned int *)&saveanchor; /* Remember pool forward */
+ saveanchor.savepoolbwd = (unsigned int *)&saveanchor; /* Remember pool backward */
-void save_free_dump(void) { /* Dump the free chain */
+ for(i=0; i < InitialSaveBloks; i++) { /* Initialize the saveareas */
- unsigned int *dsv, omsr;
- savectl *dsc;
-
- dsv = save_deb(&omsr); /* Get the virtual of the first and disable interrupts */
+ savec = (savearea_comm *)save; /* Get the control area for this one */
- while(dsv) { /* Do 'em all */
- dsc=(savectl *)((unsigned int)dsv+4096-sizeof(savectl)); /* Point to the control area */
-// printf("%08X %08X: nxt=%08X; alloc=%08X; flags=%08X\n", dsv, /* Print it all out */
-// ((unsigned int)dsv)^(dsc->sac_vrswap), dsc->sac_next, dsc->sac_alloc, dsc->sac_flags);
- dsv=(unsigned int *)(((unsigned int) dsc->sac_next)^(dsc->sac_vrswap)); /* On to the next, virtually */
+ savec->sac_alloc = 0; /* Mark it allocated */
+ savec->sac_vrswap = 0; /* V=R, so the translation factor is 0 */
+ savec->sac_flags = sac_perm; /* Mark it permanent */
+ savec->sac_flags |= 0x0000EE00; /* Debug eyecatcher */
+ save_queue((savearea *)savec); /* Add page to savearea lists */
+ save += PAGE_SIZE; /* Jump up to the next one now */
}
- __asm__ volatile ("mtmsr %0" : : "r" (omsr)); /* Restore the interruption mask */
+
+ *addrx = save; /* Move the free storage lowwater mark */
+
+/*
+ * We now have a free list that has our initial number of entries
+ * The local qfret lists is empty. When we call save_get below it will see that
+ * the local list is empty and fill it for us.
+ *
+ * It is ok to call save_get_phys here because even though if we are translation on, we are still V=R and
+ * running with BAT registers so no interruptions. Regular interruptions will be off. Using save_get
+ * would be wrong if the tracing was enabled--it would cause an exception.
+ */
+
+ save2 = (vm_offset_t)save_get_phys(); /* This will populate the local list
+ and get the first one for the system */
+ per_proc_info[0].next_savearea = (unsigned int)save2; /* Tell the exception handler about it */
+
+/*
+ * The system is now able to take interruptions
+ */
+
return;
+
}
+
+
+
/*
- * This routine prints the free savearea block chain for debugging.
+ * Returns a savearea. If the free list needs size adjustment it happens here.
+ * Don't actually allocate the savearea until after the adjustment is done.
*/
+struct savearea *save_alloc(void) { /* Reserve a save area */
+
+
+ if(saveanchor.saveadjust) save_adjust(); /* If size need adjustment, do it now */
+
+ return save_get(); /* Pass the baby... */
+}
+
+
+/*
+ * This routine releases a save area to the free queue. If after that, we have more than our maximum target,
+ * we start releasing what we can until we hit the normal target.
+ */
-void DumpTheSave(struct savearea *save) { /* Dump the free chain */
- unsigned int *r;
+void save_release(struct savearea *save) { /* Release a save area */
+
+ save_ret(save); /* Return a savearea to the free list */
+
+ if(saveanchor.saveadjust) save_adjust(); /* Adjust the savearea free list and pool size if needed */
- printf("savearea at %08X\n", save);
- printf(" srrs: %08X %08X\n", save->save_srr0, save->save_srr1);
- printf(" cr, xer, lr: %08X %08X %08X\n", save->save_cr, save->save_xer, save->save_lr);
- printf("ctr, dar, dsisr: %08X %08X %08X\n", save->save_ctr, save->save_dar, save->save_dsisr);
- printf(" space, copyin: %08X %08X\n", save->save_space, save->save_sr_copyin);
- r=&save->save_r0;
- printf(" regs: %08X %08X %08X %08X %08X %08X %08X %08X\n", r[0], r[1], r[2], r[3], r[4], r[5], r[6], r[7]);
- printf(" %08X %08X %08X %08X %08X %08X %08X %08X\n", r[8], r[9], r[10], r[11], r[12], r[13], r[14], r[15]);
- printf(" %08X %08X %08X %08X %08X %08X %08X %08X\n", r[16], r[17], r[18], r[19], r[20], r[21], r[22], r[23]);
- printf(" %08X %08X %08X %08X %08X %08X %08X %08X\n", r[24], r[25], r[29], r[27], r[28], r[29], r[30], r[31]);
- r=(unsigned int *)&save->save_fp0;
- printf(" floats: %08X%08X %08X%08X %08X%08X %08X%08X\n", r[0], r[1], r[2], r[3], r[4], r[5], r[6], r[7]);
- printf(" %08X%08X %08X%08X %08X%08X %08X%08X\n", r[8], r[9], r[10], r[11], r[12], r[13], r[14], r[15]);
- printf(" %08X%08X %08X%08X %08X%08X %08X%08X\n", r[16], r[17], r[18], r[19], r[20], r[21], r[22], r[23]);
- printf(" %08X%08X %08X%08X %08X%08X %08X%08X\n", r[24], r[25], r[29], r[27], r[28], r[29], r[30], r[31]);
- printf(" %08X%08X %08X%08X %08X%08X %08X%08X\n", r[32], r[33], r[34], r[35], r[36], r[37], r[38], r[39]);
- printf(" %08X%08X %08X%08X %08X%08X %08X%08X\n", r[40], r[41], r[42], r[43], r[44], r[45], r[46], r[47]);
- printf(" %08X%08X %08X%08X %08X%08X %08X%08X\n", r[48], r[49], r[50], r[51], r[52], r[53], r[54], r[55]);
- printf(" %08X%08X %08X%08X %08X%08X %08X%08X\n", r[56], r[57], r[58], r[59], r[60], r[61], r[62], r[63]);
- r=&save->save_sr0;
- printf(" srs: %08X %08X %08X %08X %08X %08X %08X %08X\n", r[0], r[1], r[2], r[3], r[4], r[5], r[6], r[7]);
- printf(" %08X %08X %08X %08X %08X %08X %08X %08X\n", r[8], r[9], r[10], r[11], r[12], r[13], r[14], r[15]);
- printf("prev, phys, act: %08X %08X %08X\n", save->save_prev, save->save_phys, save->save_act);
- printf(" flags: %08X\n", save->save_flags);
return;
+
}
-
-
/*
- * Dumps out savearea and stack backchains
+ * Adjusts the size of the free list. Can either release or allocate full pages
+ * of kernel memory. This can block.
+ *
+ * Note that we will only run one adjustment and the amount needed may change
+ * while we are executing.
+ *
+ * Calling this routine is triggered by saveanchor.saveadjust. This value is always calculated just before
+ * we unlock the saveanchor lock (this keeps it pretty accurate). If the total of savefreecnt and saveinuse
+ * is within the hysteresis range, it is set to 0. If outside, it is set to the number needed to bring
+ * the total to the target value. Note that there is a minimum size to the free list (FreeListMin) and if
+ * savefreecnt falls below that, saveadjust is set to the number needed to bring it to that.
*/
-
-void DumpBackChain(struct savearea *save) { /* Prints out back chains */
- unsigned int *r;
- savearea *sv;
+
+void save_adjust(void) {
- if(!backchain) return;
- printf("Proceeding back from savearea at %08X:\n", save);
- sv=save;
- while(sv) {
- printf(" curr=%08X; prev=%08X; stack=%08X\n", sv, sv->save_prev, sv->save_r1);
- sv=sv->save_prev;
+ savearea_comm *sctl, *sctlnext, *freepool, *freepage, *realpage;
+ kern_return_t ret;
+
+ if(saveanchor.saveadjust < 0) { /* Do we need to adjust down? */
+
+ sctl = (savearea_comm *)save_trim_free(); /* Trim list to the need count, return start of trim list */
+
+ while(sctl) { /* Release the free pages back to the kernel */
+ sctlnext = (savearea_comm *)sctl->save_prev; /* Get next in list */
+ kmem_free(kernel_map, (vm_offset_t) sctl, PAGE_SIZE); /* Release the page */
+ sctl = sctlnext; /* Chain onwards */
+ }
+ }
+ else { /* We need more... */
+
+ if(save_recover()) return; /* If we can recover enough from the pool, return */
+
+ while(saveanchor.saveadjust > 0) { /* Keep going until we have enough */
+
+ ret = kmem_alloc_wired(kernel_map, (vm_offset_t *)&freepage, PAGE_SIZE); /* Get a page for free pool */
+ if(ret != KERN_SUCCESS) { /* Did we get some memory? */
+ panic("Whoops... Not a bit of wired memory left for saveareas\n");
+ }
+
+ realpage = (savearea_comm *)pmap_extract(kernel_pmap, (vm_offset_t)freepage); /* Get the physical */
+
+ bzero((void *)freepage, PAGE_SIZE); /* Clear it all to zeros */
+ freepage->sac_alloc = 0; /* Mark all entries taken */
+ freepage->sac_vrswap = (unsigned int)freepage ^ (unsigned int)realpage; /* Form mask to convert V to R and vice versa */
+
+ freepage->sac_flags |= 0x0000EE00; /* Set debug eyecatcher */
+
+ save_queue((savearea *)realpage); /* Add all saveareas on page to free list */
+ }
}
- return;
}
+/*
+ * Fake up information to make the saveareas look like a zone
+ */
+save_fake_zone_info(int *count, vm_size_t *cur_size, vm_size_t *max_size, vm_size_t *elem_size,
+ vm_size_t *alloc_size, int *collectable, int *exhaustable)
+{
+ *count = saveanchor.saveinuse;
+ *cur_size = (saveanchor.savefreecnt + saveanchor.saveinuse) * (PAGE_SIZE / sac_cnt);
+ *max_size = saveanchor.savemaxcount * (PAGE_SIZE / sac_cnt);
+ *elem_size = sizeof(savearea);
+ *alloc_size = PAGE_SIZE;
+ *collectable = 1;
+ *exhaustable = 0;
+}
projects / apple / xnu.git / blobdiff