From: acevest <zhaoyanbai@126.com>
Date: Tue, 2 Nov 2021 06:16:40 +0000 (+0800)
Subject: 加快一点bootmem分配
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/static/doc/zpipe.c?a=commitdiff_plain;h=291c1981f2a5d57deb9434f5c4f8066ef8f13920;p=kernel.git

加快一点bootmem分配
---

diff --git a/include/boot/boot.h b/include/boot/boot.h
index 840cf18..ee2a068 100644
--- a/include/boot/boot.h
+++ b/include/boot/boot.h
@@ -49,8 +49,8 @@ typedef struct bootmem_data {
     unsigned long min_pfn;
     unsigned long max_pfn;
 
-    unsigned long last_offset;   // offset to pfn2pa(this->min_pfn);
-    unsigned long last_hit_pfn;  // last hit index in bitmap
+    // 准备分配的超始pfn
+    unsigned long prepare_alloc_pfn;
 
     void *bitmap;
     unsigned long mapsize;
diff --git a/mm/bootmem.c b/mm/bootmem.c
index d491194..12d3570 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -92,7 +92,7 @@ void e820_init_bootmem_data() {
 
     printk("pfn_min: %d pfn_max: %d\n", bootmem_data.min_pfn, bootmem_data.max_pfn);
 
-    bootmem_data.last_hit_pfn = bootmem_data.min_pfn;
+    bootmem_data.prepare_alloc_pfn = bootmem_data.min_pfn;
 }
 
 void register_bootmem_pages() {
@@ -179,7 +179,7 @@ void *alloc_from_bootmem(unsigned long size, char *title) {
     bootmem_data_t *pbd = &bootmem_data;
 
     // 从该处开始查找空闲区间
-    unsigned long search_bgn_pfn = pbd->min_pfn;
+    unsigned long search_bgn_pfn = pbd->prepare_alloc_pfn;
 
 find_next_block:
     // 先找到第一个空闲的pfn
@@ -214,80 +214,7 @@ find_next_block:
     reserve_bootmem(bgn_pfn, end_pfn);
     region = pfn2va(bgn_pfn);
 
-    return region;
-}
-
-void *alloc_bootmem(unsigned long size, unsigned long align) {
-    bootmem_data_t *pbd = &bootmem_data;
-
-    assert(size != 0);
-    assert((align & (align - 1)) == 0);  // must be power of 2
-
-    unsigned long fallback = 0;
-    unsigned long bgn_pfn, end_pfn, step;
-
-    step = align >> PAGE_SHIFT;
-    step = step > 0 ? step : 1;
-
-    bgn_pfn = ALIGN(pbd->min_pfn, step);
-    end_pfn = pbd->max_pfn;
-
-    // start from last position
-    if (pbd->last_hit_pfn > bgn_pfn) {
-        fallback = bgn_pfn + 1;
-        bgn_pfn = ALIGN(pbd->last_hit_pfn, step);
-    }
-
-    while (1) {
-        int merge;
-        void *region;
-        unsigned long i, search_end_pfn;
-        unsigned long start_off, end_off;
-
-    find_block:
-
-        bgn_pfn = find_next_zero_bit(pbd->bitmap, end_pfn, bgn_pfn);
-        bgn_pfn = ALIGN(bgn_pfn, step);
-
-        search_end_pfn = bgn_pfn + PFN_UP(size);
-
-        if (bgn_pfn >= end_pfn || search_end_pfn > end_pfn) break;
+    pbd->prepare_alloc_pfn = end_pfn;
 
-        for (i = bgn_pfn; i < search_end_pfn; ++i) {
-            if (bootmem_page_state(i) != BOOTMEM_PAGE_FREE) {  // space not enough
-                bgn_pfn = ALIGN(i, step);
-                if (bgn_pfn == i) bgn_pfn += step;
-
-                goto find_block;
-            }
-        }
-
-        // try to use the unused part of last page
-        if (pbd->last_offset & (PAGE_SIZE - 1) && PFN_DW(pbd->last_offset) + 1 == bgn_pfn)
-            start_off = ALIGN(pbd->last_offset, align);
-        else
-            start_off = pfn2pa(bgn_pfn);
-
-        merge = PFN_DW(start_off) < bgn_pfn;
-        end_off = start_off + size;
-
-        pbd->last_offset = end_off;
-        pbd->last_hit_pfn = PFN_UP(end_off);
-
-        reserve_bootmem(PFN_DW(start_off) + merge, PFN_UP(end_off));
-
-        region = pa2va(start_off);
-
-        memset(region, 0, size);
-
-        return region;
-    }
-
-    if (fallback) {
-        bgn_pfn = ALIGN(fallback - 1, step);
-        fallback = 0;
-        goto find_block;
-    }
-
-    return 0;
+    return region;
 }
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